From 9a56933e8cace1e2169a0ab60854ed41e12f81e1 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 14:31:43 +0000
Subject: [PATCH 01/13] Create visit_block_data for const-prop-lint.
---
compiler/rustc_mir_transform/src/const_prop_lint.rs | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 6c1980ff3ad..d042f93009e 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -14,11 +14,7 @@ use rustc_hir::HirId;
use rustc_index::bit_set::BitSet;
use rustc_index::vec::IndexVec;
use rustc_middle::mir::visit::Visitor;
-use rustc_middle::mir::{
- AssertKind, BinOp, Body, Constant, Local, LocalDecl, Location, Operand, Place, Rvalue,
- SourceInfo, SourceScope, SourceScopeData, Statement, StatementKind, Terminator, TerminatorKind,
- UnOp, RETURN_PLACE,
-};
+use rustc_middle::mir::*;
use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
use rustc_middle::ty::InternalSubsts;
use rustc_middle::ty::{
@@ -695,6 +691,10 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
| TerminatorKind::Call { .. }
| TerminatorKind::InlineAsm { .. } => {}
}
+ }
+
+ fn visit_basic_block_data(&mut self, block: BasicBlock, data: &BasicBlockData<'tcx>) {
+ self.super_basic_block_data(block, data);
// We remove all Locals which are restricted in propagation to their containing blocks and
// which were modified in the current block.
From 2247cd664368acc07529a498388ab78eed93c431 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 14:41:13 +0000
Subject: [PATCH 02/13] Simplify visit_statement.
---
.../rustc_mir_transform/src/const_prop.rs | 13 +-
.../src/const_prop_lint.rs | 113 +++++++++---------
2 files changed, 61 insertions(+), 65 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 6b2eefce24d..9a3ccc2f7e4 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -961,13 +961,14 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
}
}
}
- StatementKind::StorageLive(local) | StatementKind::StorageDead(local) => {
+ StatementKind::StorageLive(local) => {
let frame = self.ecx.frame_mut();
- frame.locals[local].value = if let StatementKind::StorageLive(_) = statement.kind {
- LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit))
- } else {
- LocalValue::Dead
- };
+ frame.locals[local].value =
+ LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit));
+ }
+ StatementKind::StorageDead(local) => {
+ let frame = self.ecx.frame_mut();
+ frame.locals[local].value = LocalValue::Dead;
}
_ => {}
}
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index d042f93009e..030d79ac22d 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -522,75 +522,70 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
trace!("visit_statement: {:?}", statement);
let source_info = statement.source_info;
self.source_info = Some(source_info);
- if let StatementKind::Assign(box (place, ref rval)) = statement.kind {
- let can_const_prop = self.ecx.machine.can_const_prop[place.local];
- if let Some(()) = self.const_prop(rval, source_info, place) {
- match can_const_prop {
- ConstPropMode::OnlyInsideOwnBlock => {
- trace!(
- "found local restricted to its block. \
+ match statement.kind {
+ StatementKind::Assign(box (place, ref rval)) => {
+ let can_const_prop = self.ecx.machine.can_const_prop[place.local];
+ if let Some(()) = self.const_prop(rval, source_info, place) {
+ match can_const_prop {
+ ConstPropMode::OnlyInsideOwnBlock => {
+ trace!(
+ "found local restricted to its block. \
Will remove it from const-prop after block is finished. Local: {:?}",
- place.local
- );
- }
- ConstPropMode::OnlyPropagateInto | ConstPropMode::NoPropagation => {
- trace!("can't propagate into {:?}", place);
- if place.local != RETURN_PLACE {
- Self::remove_const(&mut self.ecx, place.local);
+ place.local
+ );
}
- }
- ConstPropMode::FullConstProp => {}
- }
- } else {
- // Const prop failed, so erase the destination, ensuring that whatever happens
- // from here on, does not know about the previous value.
- // This is important in case we have
- // ```rust
- // let mut x = 42;
- // x = SOME_MUTABLE_STATIC;
- // // x must now be uninit
- // ```
- // FIXME: we overzealously erase the entire local, because that's easier to
- // implement.
- trace!(
- "propagation into {:?} failed.
- Nuking the entire site from orbit, it's the only way to be sure",
- place,
- );
- Self::remove_const(&mut self.ecx, place.local);
- }
- } else {
- match statement.kind {
- StatementKind::SetDiscriminant { ref place, .. } => {
- match self.ecx.machine.can_const_prop[place.local] {
- ConstPropMode::FullConstProp | ConstPropMode::OnlyInsideOwnBlock => {
- if self
- .use_ecx(source_info, |this| this.ecx.statement(statement))
- .is_some()
- {
- trace!("propped discriminant into {:?}", place);
- } else {
+ ConstPropMode::OnlyPropagateInto | ConstPropMode::NoPropagation => {
+ trace!("can't propagate into {:?}", place);
+ if place.local != RETURN_PLACE {
Self::remove_const(&mut self.ecx, place.local);
}
}
- ConstPropMode::OnlyPropagateInto | ConstPropMode::NoPropagation => {
+ ConstPropMode::FullConstProp => {}
+ }
+ } else {
+ // Const prop failed, so erase the destination, ensuring that whatever happens
+ // from here on, does not know about the previous value.
+ // This is important in case we have
+ // ```rust
+ // let mut x = 42;
+ // x = SOME_MUTABLE_STATIC;
+ // // x must now be uninit
+ // ```
+ // FIXME: we overzealously erase the entire local, because that's easier to
+ // implement.
+ trace!(
+ "propagation into {:?} failed.
+ Nuking the entire site from orbit, it's the only way to be sure",
+ place,
+ );
+ Self::remove_const(&mut self.ecx, place.local);
+ }
+ }
+ StatementKind::SetDiscriminant { ref place, .. } => {
+ match self.ecx.machine.can_const_prop[place.local] {
+ ConstPropMode::FullConstProp | ConstPropMode::OnlyInsideOwnBlock => {
+ if self.use_ecx(source_info, |this| this.ecx.statement(statement)).is_some()
+ {
+ trace!("propped discriminant into {:?}", place);
+ } else {
Self::remove_const(&mut self.ecx, place.local);
}
}
+ ConstPropMode::OnlyPropagateInto | ConstPropMode::NoPropagation => {
+ Self::remove_const(&mut self.ecx, place.local);
+ }
}
- StatementKind::StorageLive(local) | StatementKind::StorageDead(local) => {
- let frame = self.ecx.frame_mut();
- frame.locals[local].value =
- if let StatementKind::StorageLive(_) = statement.kind {
- LocalValue::Live(interpret::Operand::Immediate(
- interpret::Immediate::Uninit,
- ))
- } else {
- LocalValue::Dead
- };
- }
- _ => {}
}
+ StatementKind::StorageLive(local) => {
+ let frame = self.ecx.frame_mut();
+ frame.locals[local].value =
+ LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit));
+ }
+ StatementKind::StorageDead(local) => {
+ let frame = self.ecx.frame_mut();
+ frame.locals[local].value = LocalValue::Dead;
+ }
+ _ => {}
}
self.super_statement(statement, location);
From 0e64ce7c5e6c15655ba99c1cbd7f3fe4f6125eb8 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Sun, 5 Mar 2023 21:37:39 +0000
Subject: [PATCH 03/13] Do not track span in ConstProp.
---
.../rustc_mir_transform/src/const_prop.rs | 39 +++++--------------
.../discriminant.main.ConstProp.64bit.diff | 2 +-
.../invalid_constant.main.ConstProp.diff | 4 +-
...float_to_exponential_common.ConstProp.diff | 4 +-
4 files changed, 14 insertions(+), 35 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 9a3ccc2f7e4..afc5f08b2d2 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -17,7 +17,7 @@ use rustc_middle::mir::*;
use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
use rustc_middle::ty::InternalSubsts;
use rustc_middle::ty::{self, ConstKind, Instance, ParamEnv, Ty, TyCtxt, TypeVisitableExt};
-use rustc_span::{def_id::DefId, Span};
+use rustc_span::{def_id::DefId, Span, DUMMY_SP};
use rustc_target::abi::{self, Align, HasDataLayout, Size, TargetDataLayout};
use rustc_target::spec::abi::Abi as CallAbi;
use rustc_trait_selection::traits;
@@ -328,9 +328,6 @@ struct ConstPropagator<'mir, 'tcx> {
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
local_decls: &'mir IndexVec<Local, LocalDecl<'tcx>>,
- // Because we have `MutVisitor` we can't obtain the `SourceInfo` from a `Location`. So we store
- // the last known `SourceInfo` here and just keep revisiting it.
- source_info: Option<SourceInfo>,
}
impl<'tcx> LayoutOfHelpers<'tcx> for ConstPropagator<'_, 'tcx> {
@@ -411,13 +408,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
)
.expect("failed to push initial stack frame");
- ConstPropagator {
- ecx,
- tcx,
- param_env,
- local_decls: &dummy_body.local_decls,
- source_info: None,
- }
+ ConstPropagator { ecx, tcx, param_env, local_decls: &dummy_body.local_decls }
}
fn get_const(&self, place: Place<'tcx>) -> Option<OpTy<'tcx>> {
@@ -495,7 +486,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
*operand = self.operand_from_scalar(
scalar,
value.layout.ty,
- self.source_info.unwrap().span,
+ DUMMY_SP,
);
}
}
@@ -629,12 +620,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
}))
}
- fn replace_with_const(
- &mut self,
- rval: &mut Rvalue<'tcx>,
- value: &OpTy<'tcx>,
- source_info: SourceInfo,
- ) {
+ fn replace_with_const(&mut self, rval: &mut Rvalue<'tcx>, value: &OpTy<'tcx>) {
if let Rvalue::Use(Operand::Constant(c)) = rval {
match c.literal {
ConstantKind::Ty(c) if matches!(c.kind(), ConstKind::Unevaluated(..)) => {}
@@ -664,11 +650,8 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
if let Some(Right(imm)) = imm {
match *imm {
interpret::Immediate::Scalar(scalar) => {
- *rval = Rvalue::Use(self.operand_from_scalar(
- scalar,
- value.layout.ty,
- source_info.span,
- ));
+ *rval =
+ Rvalue::Use(self.operand_from_scalar(scalar, value.layout.ty, DUMMY_SP));
}
Immediate::ScalarPair(..) => {
// Found a value represented as a pair. For now only do const-prop if the type
@@ -701,7 +684,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
let const_val = ConstValue::ByRef { alloc, offset: Size::ZERO };
let literal = ConstantKind::Val(const_val, ty);
*rval = Rvalue::Use(Operand::Constant(Box::new(Constant {
- span: source_info.span,
+ span: DUMMY_SP,
user_ty: None,
literal,
})));
@@ -894,8 +877,6 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
trace!("visit_statement: {:?}", statement);
- let source_info = statement.source_info;
- self.source_info = Some(source_info);
match statement.kind {
StatementKind::Assign(box (place, ref mut rval)) => {
let can_const_prop = self.ecx.machine.can_const_prop[place.local];
@@ -905,7 +886,7 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
// consists solely of uninitialized memory (so it doesn't capture any locals).
if let Some(ref value) = self.get_const(place) && self.should_const_prop(value) {
trace!("replacing {:?} with {:?}", rval, value);
- self.replace_with_const(rval, value, source_info);
+ self.replace_with_const(rval, value);
if can_const_prop == ConstPropMode::FullConstProp
|| can_const_prop == ConstPropMode::OnlyInsideOwnBlock
{
@@ -977,8 +958,6 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
}
fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, location: Location) {
- let source_info = terminator.source_info;
- self.source_info = Some(source_info);
self.super_terminator(terminator, location);
match &mut terminator.kind {
@@ -991,7 +970,7 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
*cond = self.operand_from_scalar(
value_const,
self.tcx.types.bool,
- source_info.span,
+ DUMMY_SP,
);
}
}
diff --git a/tests/mir-opt/const_prop/discriminant.main.ConstProp.64bit.diff b/tests/mir-opt/const_prop/discriminant.main.ConstProp.64bit.diff
index b9a10704be0..6d8738aa61a 100644
--- a/tests/mir-opt/const_prop/discriminant.main.ConstProp.64bit.diff
+++ b/tests/mir-opt/const_prop/discriminant.main.ConstProp.64bit.diff
@@ -22,7 +22,7 @@
- switchInt(move _4) -> [1: bb1, otherwise: bb3]; // scope 2 at $DIR/discriminant.rs:+1:21: +1:31
+ _3 = const Option::<bool>::Some(true); // scope 2 at $DIR/discriminant.rs:+1:34: +1:44
+ // mir::Constant
-+ // + span: $DIR/discriminant.rs:12:34: 12:44
++ // + span: no-location
+ // + literal: Const { ty: Option<bool>, val: Value(Scalar(0x01)) }
+ _4 = const 1_isize; // scope 2 at $DIR/discriminant.rs:+1:21: +1:31
+ switchInt(const 1_isize) -> [1: bb1, otherwise: bb3]; // scope 2 at $DIR/discriminant.rs:+1:21: +1:31
diff --git a/tests/mir-opt/const_prop/invalid_constant.main.ConstProp.diff b/tests/mir-opt/const_prop/invalid_constant.main.ConstProp.diff
index 4f056dd85e3..a38c1de2a78 100644
--- a/tests/mir-opt/const_prop/invalid_constant.main.ConstProp.diff
+++ b/tests/mir-opt/const_prop/invalid_constant.main.ConstProp.diff
@@ -44,11 +44,11 @@
- _3 = [move _4]; // scope 1 at $DIR/invalid_constant.rs:+13:24: +13:60
+ _4 = const Scalar(0x00000004): E; // scope 4 at $DIR/invalid_constant.rs:+13:34: +13:57
+ // mir::Constant
-+ // + span: $DIR/invalid_constant.rs:28:34: 28:57
++ // + span: no-location
+ // + literal: Const { ty: E, val: Value(Scalar(0x00000004)) }
+ _3 = [const Scalar(0x00000004): E]; // scope 1 at $DIR/invalid_constant.rs:+13:24: +13:60
+ // mir::Constant
-+ // + span: $DIR/invalid_constant.rs:28:24: 28:60
++ // + span: no-location
+ // + literal: Const { ty: E, val: Value(Scalar(0x00000004)) }
StorageDead(_4); // scope 1 at $DIR/invalid_constant.rs:+13:59: +13:60
StorageDead(_5); // scope 1 at $DIR/invalid_constant.rs:+13:60: +13:61
diff --git a/tests/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff b/tests/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
index 1f5c533815d..ec063294856 100644
--- a/tests/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
+++ b/tests/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
@@ -54,7 +54,7 @@
- _6 = MinusPlus; // scope 1 at $DIR/funky_arms.rs:+10:17: +10:41
+ _6 = const MinusPlus; // scope 1 at $DIR/funky_arms.rs:+10:17: +10:41
+ // mir::Constant
-+ // + span: $DIR/funky_arms.rs:21:17: 21:41
++ // + span: no-location
+ // + literal: Const { ty: Sign, val: Value(Scalar(0x01)) }
goto -> bb4; // scope 1 at $DIR/funky_arms.rs:+10:17: +10:41
}
@@ -63,7 +63,7 @@
- _6 = Minus; // scope 1 at $DIR/funky_arms.rs:+9:18: +9:38
+ _6 = const Minus; // scope 1 at $DIR/funky_arms.rs:+9:18: +9:38
+ // mir::Constant
-+ // + span: $DIR/funky_arms.rs:20:18: 20:38
++ // + span: no-location
+ // + literal: Const { ty: Sign, val: Value(Scalar(0x00)) }
goto -> bb4; // scope 1 at $DIR/funky_arms.rs:+9:18: +9:38
}
From 081bc75743c1d6f4a3f41df4444f70f82fbb79ab Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 08:20:10 +0000
Subject: [PATCH 04/13] Assume the frame has all the locals.
---
.../src/interpret/eval_context.rs | 30 ++++++++-----------
1 file changed, 13 insertions(+), 17 deletions(-)
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index 39c74191258..0918ffcd982 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -536,24 +536,20 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
local: mir::Local,
layout: Option<TyAndLayout<'tcx>>,
) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
- // `const_prop` runs into this with an invalid (empty) frame, so we
- // have to support that case (mostly by skipping all caching).
- match frame.locals.get(local).and_then(|state| state.layout.get()) {
- None => {
- let layout = from_known_layout(self.tcx, self.param_env, layout, || {
- let local_ty = frame.body.local_decls[local].ty;
- let local_ty =
- self.subst_from_frame_and_normalize_erasing_regions(frame, local_ty)?;
- self.layout_of(local_ty)
- })?;
- if let Some(state) = frame.locals.get(local) {
- // Layouts of locals are requested a lot, so we cache them.
- state.layout.set(Some(layout));
- }
- Ok(layout)
- }
- Some(layout) => Ok(layout),
+ let state = &frame.locals[local];
+ if let Some(layout) = state.layout.get() {
+ return Ok(layout);
}
+
+ let layout = from_known_layout(self.tcx, self.param_env, layout, || {
+ let local_ty = frame.body.local_decls[local].ty;
+ let local_ty = self.subst_from_frame_and_normalize_erasing_regions(frame, local_ty)?;
+ self.layout_of(local_ty)
+ })?;
+
+ // Layouts of locals are requested a lot, so we cache them.
+ state.layout.set(Some(layout));
+ Ok(layout)
}
/// Returns the actual dynamic size and alignment of the place at the given type.
From 24dbf9c1123716ab0589772b301468d34a7a8a9b Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 14:32:16 +0000
Subject: [PATCH 05/13] Only assign value in remove_const.
---
compiler/rustc_mir_transform/src/const_prop.rs | 12 ++++--------
compiler/rustc_mir_transform/src/const_prop_lint.rs | 10 +++-------
2 files changed, 7 insertions(+), 15 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index afc5f08b2d2..1cc4e21ea51 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -1,8 +1,6 @@
//! Propagates constants for early reporting of statically known
//! assertion failures
-use std::cell::Cell;
-
use either::Right;
use rustc_const_eval::const_eval::CheckAlignment;
@@ -25,8 +23,8 @@ use rustc_trait_selection::traits;
use crate::MirPass;
use rustc_const_eval::interpret::{
self, compile_time_machine, AllocId, ConstAllocation, ConstValue, CtfeValidationMode, Frame,
- ImmTy, Immediate, InterpCx, InterpResult, LocalState, LocalValue, MemoryKind, OpTy, PlaceTy,
- Pointer, Scalar, StackPopCleanup, StackPopUnwind,
+ ImmTy, Immediate, InterpCx, InterpResult, LocalValue, MemoryKind, OpTy, PlaceTy, Pointer,
+ Scalar, StackPopCleanup, StackPopUnwind,
};
/// The maximum number of bytes that we'll allocate space for a local or the return value.
@@ -437,10 +435,8 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
/// Remove `local` from the pool of `Locals`. Allows writing to them,
/// but not reading from them anymore.
fn remove_const(ecx: &mut InterpCx<'mir, 'tcx, ConstPropMachine<'mir, 'tcx>>, local: Local) {
- ecx.frame_mut().locals[local] = LocalState {
- value: LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit)),
- layout: Cell::new(None),
- };
+ ecx.frame_mut().locals[local].value =
+ LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit));
}
/// Returns the value, if any, of evaluating `c`.
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 030d79ac22d..f8945417006 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -1,13 +1,11 @@
//! Propagates constants for early reporting of statically known
//! assertion failures
-use std::cell::Cell;
-
use either::{Left, Right};
use rustc_const_eval::interpret::Immediate;
use rustc_const_eval::interpret::{
- self, InterpCx, InterpResult, LocalState, LocalValue, MemoryKind, OpTy, Scalar, StackPopCleanup,
+ self, InterpCx, InterpResult, LocalValue, MemoryKind, OpTy, Scalar, StackPopCleanup,
};
use rustc_hir::def::DefKind;
use rustc_hir::HirId;
@@ -254,10 +252,8 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
/// Remove `local` from the pool of `Locals`. Allows writing to them,
/// but not reading from them anymore.
fn remove_const(ecx: &mut InterpCx<'mir, 'tcx, ConstPropMachine<'mir, 'tcx>>, local: Local) {
- ecx.frame_mut().locals[local] = LocalState {
- value: LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit)),
- layout: Cell::new(None),
- };
+ ecx.frame_mut().locals[local].value =
+ LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit));
}
fn lint_root(&self, source_info: SourceInfo) -> Option<HirId> {
From 9928d0e566bebe5ffca533ef332a18375a70b83f Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 15:04:53 +0000
Subject: [PATCH 06/13] Remove OnlyPropagateInto.
---
.../rustc_mir_transform/src/const_prop.rs | 35 ++++---------------
.../src/const_prop_lint.rs | 4 +--
.../bad_op_mod_by_zero.main.ConstProp.diff | 8 +++--
3 files changed, 13 insertions(+), 34 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 1cc4e21ea51..a78b36c65f3 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -718,8 +718,6 @@ pub enum ConstPropMode {
FullConstProp,
/// The `Local` can only be propagated into and from its own block.
OnlyInsideOwnBlock,
- /// The `Local` can be propagated into but reads cannot be propagated.
- OnlyPropagateInto,
/// The `Local` cannot be part of propagation at all. Any statement
/// referencing it either for reading or writing will not get propagated.
NoPropagation,
@@ -729,8 +727,6 @@ pub struct CanConstProp {
can_const_prop: IndexVec<Local, ConstPropMode>,
// False at the beginning. Once set, no more assignments are allowed to that local.
found_assignment: BitSet<Local>,
- // Cache of locals' information
- local_kinds: IndexVec<Local, LocalKind>,
}
impl CanConstProp {
@@ -743,10 +739,6 @@ impl CanConstProp {
let mut cpv = CanConstProp {
can_const_prop: IndexVec::from_elem(ConstPropMode::FullConstProp, &body.local_decls),
found_assignment: BitSet::new_empty(body.local_decls.len()),
- local_kinds: IndexVec::from_fn_n(
- |local| body.local_kind(local),
- body.local_decls.len(),
- ),
};
for (local, val) in cpv.can_const_prop.iter_enumerated_mut() {
let ty = body.local_decls[local].ty;
@@ -759,24 +751,10 @@ impl CanConstProp {
continue;
}
}
- // Cannot use args at all
- // Cannot use locals because if x < y { y - x } else { x - y } would
- // lint for x != y
- // FIXME(oli-obk): lint variables until they are used in a condition
- // FIXME(oli-obk): lint if return value is constant
- if cpv.local_kinds[local] == LocalKind::Arg {
- *val = ConstPropMode::OnlyPropagateInto;
- trace!(
- "local {:?} can't be const propagated because it's a function argument",
- local
- );
- } else if cpv.local_kinds[local] == LocalKind::Var {
- *val = ConstPropMode::OnlyInsideOwnBlock;
- trace!(
- "local {:?} will only be propagated inside its block, because it's a user variable",
- local
- );
- }
+ }
+ // Consider that arguments are assigned on entry.
+ for arg in body.args_iter() {
+ cpv.found_assignment.insert(arg);
}
cpv.visit_body(&body);
cpv.can_const_prop
@@ -806,7 +784,6 @@ impl Visitor<'_> for CanConstProp {
// states as applicable.
ConstPropMode::OnlyInsideOwnBlock => {}
ConstPropMode::NoPropagation => {}
- ConstPropMode::OnlyPropagateInto => {}
other @ ConstPropMode::FullConstProp => {
trace!(
"local {:?} can't be propagated because of multiple assignments. Previous state: {:?}",
@@ -897,7 +874,7 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
place.local
);
}
- ConstPropMode::OnlyPropagateInto | ConstPropMode::NoPropagation => {
+ ConstPropMode::NoPropagation => {
trace!("can't propagate into {:?}", place);
if place.local != RETURN_PLACE {
Self::remove_const(&mut self.ecx, place.local);
@@ -933,7 +910,7 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
Self::remove_const(&mut self.ecx, place.local);
}
}
- ConstPropMode::OnlyPropagateInto | ConstPropMode::NoPropagation => {
+ ConstPropMode::NoPropagation => {
Self::remove_const(&mut self.ecx, place.local);
}
}
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index f8945417006..c0a1e502d85 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -530,7 +530,7 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
place.local
);
}
- ConstPropMode::OnlyPropagateInto | ConstPropMode::NoPropagation => {
+ ConstPropMode::NoPropagation => {
trace!("can't propagate into {:?}", place);
if place.local != RETURN_PLACE {
Self::remove_const(&mut self.ecx, place.local);
@@ -567,7 +567,7 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
Self::remove_const(&mut self.ecx, place.local);
}
}
- ConstPropMode::OnlyPropagateInto | ConstPropMode::NoPropagation => {
+ ConstPropMode::NoPropagation => {
Self::remove_const(&mut self.ecx, place.local);
}
}
diff --git a/tests/mir-opt/const_prop/bad_op_mod_by_zero.main.ConstProp.diff b/tests/mir-opt/const_prop/bad_op_mod_by_zero.main.ConstProp.diff
index ae9ffd519a1..bedfa5992ad 100644
--- a/tests/mir-opt/const_prop/bad_op_mod_by_zero.main.ConstProp.diff
+++ b/tests/mir-opt/const_prop/bad_op_mod_by_zero.main.ConstProp.diff
@@ -27,17 +27,19 @@
}
bb1: {
- _5 = Eq(_1, const -1_i32); // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
+- _5 = Eq(_1, const -1_i32); // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
- _6 = Eq(const 1_i32, const i32::MIN); // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
- _7 = BitAnd(move _5, move _6); // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
- assert(!move _7, "attempt to compute the remainder of `{} % {}`, which would overflow", const 1_i32, _1) -> bb2; // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
++ _5 = const false; // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
+ _6 = const false; // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
+ _7 = const false; // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
-+ assert(!const false, "attempt to compute the remainder of `{} % {}`, which would overflow", const 1_i32, _1) -> bb2; // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
++ assert(!const false, "attempt to compute the remainder of `{} % {}`, which would overflow", const 1_i32, const 0_i32) -> bb2; // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
}
bb2: {
- _2 = Rem(const 1_i32, _1); // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
+- _2 = Rem(const 1_i32, _1); // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
++ _2 = Rem(const 1_i32, const 0_i32); // scope 1 at $DIR/bad_op_mod_by_zero.rs:+2:14: +2:19
StorageDead(_2); // scope 1 at $DIR/bad_op_mod_by_zero.rs:+3:1: +3:2
return; // scope 0 at $DIR/bad_op_mod_by_zero.rs:+3:2: +3:2
}
From d97a7ce69b35b42778709333c46d87c08c2848e7 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 15:20:57 +0000
Subject: [PATCH 07/13] Refactor tracking of writes.
---
.../rustc_mir_transform/src/const_prop.rs | 82 ++++++++-----------
.../src/const_prop_lint.rs | 48 +++++------
2 files changed, 58 insertions(+), 72 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index a78b36c65f3..cf5eb697b24 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -4,7 +4,6 @@
use either::Right;
use rustc_const_eval::const_eval::CheckAlignment;
-use rustc_data_structures::fx::FxHashSet;
use rustc_hir::def::DefKind;
use rustc_index::bit_set::BitSet;
use rustc_index::vec::IndexVec;
@@ -152,24 +151,12 @@ impl<'tcx> MirPass<'tcx> for ConstProp {
pub struct ConstPropMachine<'mir, 'tcx> {
/// The virtual call stack.
stack: Vec<Frame<'mir, 'tcx>>,
- /// `OnlyInsideOwnBlock` locals that were written in the current block get erased at the end.
- pub written_only_inside_own_block_locals: FxHashSet<Local>,
- /// Locals that need to be cleared after every block terminates.
- pub only_propagate_inside_block_locals: BitSet<Local>,
pub can_const_prop: IndexVec<Local, ConstPropMode>,
}
impl ConstPropMachine<'_, '_> {
- pub fn new(
- only_propagate_inside_block_locals: BitSet<Local>,
- can_const_prop: IndexVec<Local, ConstPropMode>,
- ) -> Self {
- Self {
- stack: Vec::new(),
- written_only_inside_own_block_locals: Default::default(),
- only_propagate_inside_block_locals,
- can_const_prop,
- }
+ pub fn new(can_const_prop: IndexVec<Local, ConstPropMode>) -> Self {
+ Self { stack: Vec::new(), can_const_prop }
}
}
@@ -255,16 +242,14 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx>
frame: usize,
local: Local,
) -> InterpResult<'tcx, &'a mut interpret::Operand<Self::Provenance>> {
- if ecx.machine.can_const_prop[local] == ConstPropMode::NoPropagation {
- throw_machine_stop_str!("tried to write to a local that is marked as not propagatable")
- }
- if frame == 0 && ecx.machine.only_propagate_inside_block_locals.contains(local) {
- trace!(
- "mutating local {:?} which is restricted to its block. \
- Will remove it from const-prop after block is finished.",
- local
- );
- ecx.machine.written_only_inside_own_block_locals.insert(local);
+ assert_eq!(frame, 0);
+ match ecx.machine.can_const_prop[local] {
+ ConstPropMode::NoPropagation => {
+ throw_machine_stop_str!(
+ "tried to write to a local that is marked as not propagatable"
+ )
+ }
+ ConstPropMode::OnlyInsideOwnBlock | ConstPropMode::FullConstProp => {}
}
ecx.machine.stack[frame].locals[local].access_mut()
}
@@ -369,17 +354,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
let param_env = tcx.param_env_reveal_all_normalized(def_id);
let can_const_prop = CanConstProp::check(tcx, param_env, body);
- let mut only_propagate_inside_block_locals = BitSet::new_empty(can_const_prop.len());
- for (l, mode) in can_const_prop.iter_enumerated() {
- if *mode == ConstPropMode::OnlyInsideOwnBlock {
- only_propagate_inside_block_locals.insert(l);
- }
- }
let mut ecx = InterpCx::new(
tcx,
tcx.def_span(def_id),
param_env,
- ConstPropMachine::new(only_propagate_inside_block_locals, can_const_prop),
+ ConstPropMachine::new(can_const_prop),
);
let ret_layout = ecx
@@ -977,26 +956,33 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
fn visit_basic_block_data(&mut self, block: BasicBlock, data: &mut BasicBlockData<'tcx>) {
self.super_basic_block_data(block, data);
+ let ensure_not_propagated = |this: &mut Self, local: Local| {
+ if cfg!(debug_assertions) {
+ assert!(
+ this.get_const(local.into()).is_none()
+ || this
+ .layout_of(this.local_decls[local].ty)
+ .map_or(true, |layout| layout.is_zst()),
+ "failed to remove values for `{local:?}`, value={:?}",
+ this.get_const(local.into()),
+ )
+ }
+ };
+
// We remove all Locals which are restricted in propagation to their containing blocks and
// which were modified in the current block.
// Take it out of the ecx so we can get a mutable reference to the ecx for `remove_const`.
- let mut locals = std::mem::take(&mut self.ecx.machine.written_only_inside_own_block_locals);
- for &local in locals.iter() {
- Self::remove_const(&mut self.ecx, local);
- }
- locals.clear();
- // Put it back so we reuse the heap of the storage
- self.ecx.machine.written_only_inside_own_block_locals = locals;
- if cfg!(debug_assertions) {
- // Ensure we are correctly erasing locals with the non-debug-assert logic.
- for local in self.ecx.machine.only_propagate_inside_block_locals.iter() {
- assert!(
- self.get_const(local.into()).is_none()
- || self
- .layout_of(self.local_decls[local].ty)
- .map_or(true, |layout| layout.is_zst())
- )
+ let can_const_prop = std::mem::take(&mut self.ecx.machine.can_const_prop);
+ for (local, &mode) in can_const_prop.iter_enumerated() {
+ match mode {
+ ConstPropMode::FullConstProp => {}
+ ConstPropMode::NoPropagation => ensure_not_propagated(self, local),
+ ConstPropMode::OnlyInsideOwnBlock => {
+ Self::remove_const(&mut self.ecx, local);
+ ensure_not_propagated(self, local);
+ }
}
}
+ self.ecx.machine.can_const_prop = can_const_prop;
}
}
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index c0a1e502d85..52c86fae7b4 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -9,7 +9,6 @@ use rustc_const_eval::interpret::{
};
use rustc_hir::def::DefKind;
use rustc_hir::HirId;
-use rustc_index::bit_set::BitSet;
use rustc_index::vec::IndexVec;
use rustc_middle::mir::visit::Visitor;
use rustc_middle::mir::*;
@@ -179,17 +178,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
let param_env = tcx.param_env_reveal_all_normalized(def_id);
let can_const_prop = CanConstProp::check(tcx, param_env, body);
- let mut only_propagate_inside_block_locals = BitSet::new_empty(can_const_prop.len());
- for (l, mode) in can_const_prop.iter_enumerated() {
- if *mode == ConstPropMode::OnlyInsideOwnBlock {
- only_propagate_inside_block_locals.insert(l);
- }
- }
let mut ecx = InterpCx::new(
tcx,
tcx.def_span(def_id),
param_env,
- ConstPropMachine::new(only_propagate_inside_block_locals, can_const_prop),
+ ConstPropMachine::new(can_const_prop),
);
let ret_layout = ecx
@@ -687,26 +680,33 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
fn visit_basic_block_data(&mut self, block: BasicBlock, data: &BasicBlockData<'tcx>) {
self.super_basic_block_data(block, data);
+ let ensure_not_propagated = |this: &mut Self, local: Local| {
+ if cfg!(debug_assertions) {
+ assert!(
+ this.get_const(local.into()).is_none()
+ || this
+ .layout_of(this.local_decls[local].ty)
+ .map_or(true, |layout| layout.is_zst()),
+ "failed to remove values for `{local:?}`, value={:?}",
+ this.get_const(local.into()),
+ )
+ }
+ };
+
// We remove all Locals which are restricted in propagation to their containing blocks and
// which were modified in the current block.
// Take it out of the ecx so we can get a mutable reference to the ecx for `remove_const`.
- let mut locals = std::mem::take(&mut self.ecx.machine.written_only_inside_own_block_locals);
- for &local in locals.iter() {
- Self::remove_const(&mut self.ecx, local);
- }
- locals.clear();
- // Put it back so we reuse the heap of the storage
- self.ecx.machine.written_only_inside_own_block_locals = locals;
- if cfg!(debug_assertions) {
- // Ensure we are correctly erasing locals with the non-debug-assert logic.
- for local in self.ecx.machine.only_propagate_inside_block_locals.iter() {
- assert!(
- self.get_const(local.into()).is_none()
- || self
- .layout_of(self.local_decls[local].ty)
- .map_or(true, |layout| layout.is_zst())
- )
+ let can_const_prop = std::mem::take(&mut self.ecx.machine.can_const_prop);
+ for (local, &mode) in can_const_prop.iter_enumerated() {
+ match mode {
+ ConstPropMode::FullConstProp => {}
+ ConstPropMode::NoPropagation => ensure_not_propagated(self, local),
+ ConstPropMode::OnlyInsideOwnBlock => {
+ Self::remove_const(&mut self.ecx, local);
+ ensure_not_propagated(self, local);
+ }
}
}
+ self.ecx.machine.can_const_prop = can_const_prop;
}
}
From f00be8b77bbbc614662a1e8349463aca45c01e62 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 15:40:38 +0000
Subject: [PATCH 08/13] Recurse into statement before applying its effect.
---
compiler/rustc_mir_transform/src/const_prop.rs | 6 ++++--
compiler/rustc_mir_transform/src/const_prop_lint.rs | 6 ++++--
tests/ui/consts/const-err-late.stderr | 12 ++++++------
3 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index cf5eb697b24..fa8c22ceb40 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -829,6 +829,10 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
trace!("visit_statement: {:?}", statement);
+
+ // Recurse into statement before applying the assignment.
+ self.super_statement(statement, location);
+
match statement.kind {
StatementKind::Assign(box (place, ref mut rval)) => {
let can_const_prop = self.ecx.machine.can_const_prop[place.local];
@@ -905,8 +909,6 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
}
_ => {}
}
-
- self.super_statement(statement, location);
}
fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, location: Location) {
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 52c86fae7b4..b7835f842ba 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -511,6 +511,10 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
trace!("visit_statement: {:?}", statement);
let source_info = statement.source_info;
self.source_info = Some(source_info);
+
+ // Recurse into statement before applying the assignment.
+ self.super_statement(statement, location);
+
match statement.kind {
StatementKind::Assign(box (place, ref rval)) => {
let can_const_prop = self.ecx.machine.can_const_prop[place.local];
@@ -576,8 +580,6 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
}
_ => {}
}
-
- self.super_statement(statement, location);
}
fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
diff --git a/tests/ui/consts/const-err-late.stderr b/tests/ui/consts/const-err-late.stderr
index cb0cab2444b..192b9ba204b 100644
--- a/tests/ui/consts/const-err-late.stderr
+++ b/tests/ui/consts/const-err-late.stderr
@@ -10,12 +10,6 @@ note: erroneous constant used
LL | black_box((S::<i32>::FOO, S::<u32>::FOO));
| ^^^^^^^^^^^^^
-note: erroneous constant used
- --> $DIR/const-err-late.rs:19:16
- |
-LL | black_box((S::<i32>::FOO, S::<u32>::FOO));
- | ^^^^^^^^^^^^^
-
error[E0080]: evaluation of `S::<u32>::FOO` failed
--> $DIR/const-err-late.rs:13:21
|
@@ -34,6 +28,12 @@ note: erroneous constant used
LL | black_box((S::<i32>::FOO, S::<u32>::FOO));
| ^^^^^^^^^^^^^
+note: erroneous constant used
+ --> $DIR/const-err-late.rs:19:16
+ |
+LL | black_box((S::<i32>::FOO, S::<u32>::FOO));
+ | ^^^^^^^^^^^^^
+
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0080`.
From b55c4f8312d48c83fc4dc3ef8b9f167c97a4d459 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 16:34:11 +0000
Subject: [PATCH 09/13] Separate checking rvalue from evaluation.
---
.../rustc_mir_transform/src/const_prop.rs | 112 +++++++++---------
.../src/const_prop_lint.rs | 97 +++++++--------
2 files changed, 100 insertions(+), 109 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index fa8c22ceb40..6e590981357 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -470,7 +470,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
}
}
- fn const_prop(&mut self, rvalue: &Rvalue<'tcx>, place: Place<'tcx>) -> Option<()> {
+ fn check_rvalue(&mut self, rvalue: &Rvalue<'tcx>) -> Option<()> {
// Perform any special handling for specific Rvalue types.
// Generally, checks here fall into one of two categories:
// 1. Additional checking to provide useful lints to the user
@@ -527,7 +527,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
return None;
}
- self.eval_rvalue_with_identities(rvalue, place)
+ Some(())
}
// Attempt to use algebraic identities to eliminate constant expressions
@@ -595,7 +595,16 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
}))
}
- fn replace_with_const(&mut self, rval: &mut Rvalue<'tcx>, value: &OpTy<'tcx>) {
+ fn replace_with_const(&mut self, place: Place<'tcx>, rval: &mut Rvalue<'tcx>) {
+ // This will return None if the above `const_prop` invocation only "wrote" a
+ // type whose creation requires no write. E.g. a generator whose initial state
+ // consists solely of uninitialized memory (so it doesn't capture any locals).
+ let Some(ref value) = self.get_const(place) else { return };
+ if !self.should_const_prop(value) {
+ return;
+ }
+ trace!("replacing {:?}={:?} with {:?}", place, rval, value);
+
if let Rvalue::Use(Operand::Constant(c)) = rval {
match c.literal {
ConstantKind::Ty(c) if matches!(c.kind(), ConstKind::Unevaluated(..)) => {}
@@ -688,6 +697,19 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
_ => false,
}
}
+
+ fn ensure_not_propagated(&mut self, local: Local) {
+ if cfg!(debug_assertions) {
+ assert!(
+ self.get_const(local.into()).is_none()
+ || self
+ .layout_of(self.local_decls[local].ty)
+ .map_or(true, |layout| layout.is_zst()),
+ "failed to remove values for `{local:?}`, value={:?}",
+ self.get_const(local.into()),
+ )
+ }
+ }
}
/// The mode that `ConstProp` is allowed to run in for a given `Local`.
@@ -827,44 +849,23 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
self.eval_constant(constant);
}
- fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
- trace!("visit_statement: {:?}", statement);
+ fn visit_assign(
+ &mut self,
+ place: &mut Place<'tcx>,
+ rvalue: &mut Rvalue<'tcx>,
+ location: Location,
+ ) {
+ self.super_assign(place, rvalue, location);
- // Recurse into statement before applying the assignment.
- self.super_statement(statement, location);
+ let Some(()) = self.check_rvalue(rvalue) else { return };
- match statement.kind {
- StatementKind::Assign(box (place, ref mut rval)) => {
- let can_const_prop = self.ecx.machine.can_const_prop[place.local];
- if let Some(()) = self.const_prop(rval, place) {
- // This will return None if the above `const_prop` invocation only "wrote" a
- // type whose creation requires no write. E.g. a generator whose initial state
- // consists solely of uninitialized memory (so it doesn't capture any locals).
- if let Some(ref value) = self.get_const(place) && self.should_const_prop(value) {
- trace!("replacing {:?} with {:?}", rval, value);
- self.replace_with_const(rval, value);
- if can_const_prop == ConstPropMode::FullConstProp
- || can_const_prop == ConstPropMode::OnlyInsideOwnBlock
- {
- trace!("propagated into {:?}", place);
- }
- }
- match can_const_prop {
- ConstPropMode::OnlyInsideOwnBlock => {
- trace!(
- "found local restricted to its block. \
- Will remove it from const-prop after block is finished. Local: {:?}",
- place.local
- );
- }
- ConstPropMode::NoPropagation => {
- trace!("can't propagate into {:?}", place);
- if place.local != RETURN_PLACE {
- Self::remove_const(&mut self.ecx, place.local);
- }
- }
- ConstPropMode::FullConstProp => {}
- }
+ match self.ecx.machine.can_const_prop[place.local] {
+ // Do nothing if the place is indirect.
+ _ if place.is_indirect() => {}
+ ConstPropMode::NoPropagation => self.ensure_not_propagated(place.local),
+ ConstPropMode::OnlyInsideOwnBlock | ConstPropMode::FullConstProp => {
+ if let Some(()) = self.eval_rvalue_with_identities(rvalue, *place) {
+ self.replace_with_const(*place, rvalue);
} else {
// Const prop failed, so erase the destination, ensuring that whatever happens
// from here on, does not know about the previous value.
@@ -884,8 +885,21 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
Self::remove_const(&mut self.ecx, place.local);
}
}
+ }
+ }
+
+ fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
+ trace!("visit_statement: {:?}", statement);
+
+ // Recurse into statement before applying the assignment.
+ self.super_statement(statement, location);
+
+ match statement.kind {
StatementKind::SetDiscriminant { ref place, .. } => {
match self.ecx.machine.can_const_prop[place.local] {
+ // Do nothing if the place is indirect.
+ _ if place.is_indirect() => {}
+ ConstPropMode::NoPropagation => self.ensure_not_propagated(place.local),
ConstPropMode::FullConstProp | ConstPropMode::OnlyInsideOwnBlock => {
if self.ecx.statement(statement).is_ok() {
trace!("propped discriminant into {:?}", place);
@@ -893,9 +907,6 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
Self::remove_const(&mut self.ecx, place.local);
}
}
- ConstPropMode::NoPropagation => {
- Self::remove_const(&mut self.ecx, place.local);
- }
}
}
StatementKind::StorageLive(local) => {
@@ -958,19 +969,6 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
fn visit_basic_block_data(&mut self, block: BasicBlock, data: &mut BasicBlockData<'tcx>) {
self.super_basic_block_data(block, data);
- let ensure_not_propagated = |this: &mut Self, local: Local| {
- if cfg!(debug_assertions) {
- assert!(
- this.get_const(local.into()).is_none()
- || this
- .layout_of(this.local_decls[local].ty)
- .map_or(true, |layout| layout.is_zst()),
- "failed to remove values for `{local:?}`, value={:?}",
- this.get_const(local.into()),
- )
- }
- };
-
// We remove all Locals which are restricted in propagation to their containing blocks and
// which were modified in the current block.
// Take it out of the ecx so we can get a mutable reference to the ecx for `remove_const`.
@@ -978,10 +976,10 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
for (local, &mode) in can_const_prop.iter_enumerated() {
match mode {
ConstPropMode::FullConstProp => {}
- ConstPropMode::NoPropagation => ensure_not_propagated(self, local),
+ ConstPropMode::NoPropagation => self.ensure_not_propagated(local),
ConstPropMode::OnlyInsideOwnBlock => {
Self::remove_const(&mut self.ecx, local);
- ensure_not_propagated(self, local);
+ self.ensure_not_propagated(local);
}
}
}
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index b7835f842ba..28198781fd9 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -405,12 +405,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
Some(())
}
- fn const_prop(
- &mut self,
- rvalue: &Rvalue<'tcx>,
- source_info: SourceInfo,
- place: Place<'tcx>,
- ) -> Option<()> {
+ fn check_rvalue(&mut self, rvalue: &Rvalue<'tcx>, source_info: SourceInfo) -> Option<()> {
// Perform any special handling for specific Rvalue types.
// Generally, checks here fall into one of two categories:
// 1. Additional checking to provide useful lints to the user
@@ -486,7 +481,20 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
return None;
}
- self.use_ecx(source_info, |this| this.ecx.eval_rvalue_into_place(rvalue, place))
+ Some(())
+ }
+
+ fn ensure_not_propagated(&mut self, local: Local) {
+ if cfg!(debug_assertions) {
+ assert!(
+ self.get_const(local.into()).is_none()
+ || self
+ .layout_of(self.local_decls[local].ty)
+ .map_or(true, |layout| layout.is_zst()),
+ "failed to remove values for `{local:?}`, value={:?}",
+ self.get_const(local.into()),
+ )
+ }
}
}
@@ -507,35 +515,21 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
self.eval_constant(constant, self.source_info.unwrap());
}
- fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
- trace!("visit_statement: {:?}", statement);
- let source_info = statement.source_info;
- self.source_info = Some(source_info);
+ fn visit_assign(&mut self, place: &Place<'tcx>, rvalue: &Rvalue<'tcx>, location: Location) {
+ self.super_assign(place, rvalue, location);
- // Recurse into statement before applying the assignment.
- self.super_statement(statement, location);
+ let source_info = self.source_info.unwrap();
+ let Some(()) = self.check_rvalue(rvalue, source_info) else { return };
- match statement.kind {
- StatementKind::Assign(box (place, ref rval)) => {
- let can_const_prop = self.ecx.machine.can_const_prop[place.local];
- if let Some(()) = self.const_prop(rval, source_info, place) {
- match can_const_prop {
- ConstPropMode::OnlyInsideOwnBlock => {
- trace!(
- "found local restricted to its block. \
- Will remove it from const-prop after block is finished. Local: {:?}",
- place.local
- );
- }
- ConstPropMode::NoPropagation => {
- trace!("can't propagate into {:?}", place);
- if place.local != RETURN_PLACE {
- Self::remove_const(&mut self.ecx, place.local);
- }
- }
- ConstPropMode::FullConstProp => {}
- }
- } else {
+ match self.ecx.machine.can_const_prop[place.local] {
+ // Do nothing if the place is indirect.
+ _ if place.is_indirect() => {}
+ ConstPropMode::NoPropagation => self.ensure_not_propagated(place.local),
+ ConstPropMode::OnlyInsideOwnBlock | ConstPropMode::FullConstProp => {
+ if self
+ .use_ecx(source_info, |this| this.ecx.eval_rvalue_into_place(rvalue, *place))
+ .is_none()
+ {
// Const prop failed, so erase the destination, ensuring that whatever happens
// from here on, does not know about the previous value.
// This is important in case we have
@@ -554,8 +548,23 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
Self::remove_const(&mut self.ecx, place.local);
}
}
+ }
+ }
+
+ fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
+ trace!("visit_statement: {:?}", statement);
+ let source_info = statement.source_info;
+ self.source_info = Some(source_info);
+
+ // Recurse into statement before applying the assignment.
+ self.super_statement(statement, location);
+
+ match statement.kind {
StatementKind::SetDiscriminant { ref place, .. } => {
match self.ecx.machine.can_const_prop[place.local] {
+ // Do nothing if the place is indirect.
+ _ if place.is_indirect() => {}
+ ConstPropMode::NoPropagation => self.ensure_not_propagated(place.local),
ConstPropMode::FullConstProp | ConstPropMode::OnlyInsideOwnBlock => {
if self.use_ecx(source_info, |this| this.ecx.statement(statement)).is_some()
{
@@ -564,9 +573,6 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
Self::remove_const(&mut self.ecx, place.local);
}
}
- ConstPropMode::NoPropagation => {
- Self::remove_const(&mut self.ecx, place.local);
- }
}
}
StatementKind::StorageLive(local) => {
@@ -682,19 +688,6 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
fn visit_basic_block_data(&mut self, block: BasicBlock, data: &BasicBlockData<'tcx>) {
self.super_basic_block_data(block, data);
- let ensure_not_propagated = |this: &mut Self, local: Local| {
- if cfg!(debug_assertions) {
- assert!(
- this.get_const(local.into()).is_none()
- || this
- .layout_of(this.local_decls[local].ty)
- .map_or(true, |layout| layout.is_zst()),
- "failed to remove values for `{local:?}`, value={:?}",
- this.get_const(local.into()),
- )
- }
- };
-
// We remove all Locals which are restricted in propagation to their containing blocks and
// which were modified in the current block.
// Take it out of the ecx so we can get a mutable reference to the ecx for `remove_const`.
@@ -702,10 +695,10 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
for (local, &mode) in can_const_prop.iter_enumerated() {
match mode {
ConstPropMode::FullConstProp => {}
- ConstPropMode::NoPropagation => ensure_not_propagated(self, local),
+ ConstPropMode::NoPropagation => self.ensure_not_propagated(local),
ConstPropMode::OnlyInsideOwnBlock => {
Self::remove_const(&mut self.ecx, local);
- ensure_not_propagated(self, local);
+ self.ensure_not_propagated(local);
}
}
}
From 0d56034a25b149ac51ae2b497c3f33ca8c838786 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 17:12:42 +0000
Subject: [PATCH 10/13] Make comment more explicit.
---
compiler/rustc_mir_transform/src/const_prop.rs | 3 ++-
compiler/rustc_mir_transform/src/const_prop_lint.rs | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 6e590981357..334dd90d4ae 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -891,7 +891,8 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
trace!("visit_statement: {:?}", statement);
- // Recurse into statement before applying the assignment.
+ // We want to evaluate operands before any change to the assigned-to value,
+ // so we recurse first.
self.super_statement(statement, location);
match statement.kind {
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 28198781fd9..cbf29380ff2 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -556,7 +556,8 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
let source_info = statement.source_info;
self.source_info = Some(source_info);
- // Recurse into statement before applying the assignment.
+ // We want to evaluate operands before any change to the assigned-to value,
+ // so we recurse first.
self.super_statement(statement, location);
match statement.kind {
From a5a01b21e62892c3f8fe735a3789d10fb31d9916 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 7 Mar 2023 17:51:48 +0000
Subject: [PATCH 11/13] Fortify clippy tests.
---
src/tools/clippy/tests/ui/erasing_op.rs | 8 +++++---
src/tools/clippy/tests/ui/erasing_op.stderr | 10 +++++-----
src/tools/clippy/tests/ui/integer_arithmetic.rs | 2 +-
.../tests/ui/overflow_check_conditional.rs | 9 +++++----
.../tests/ui/overflow_check_conditional.stderr | 16 ++++++++--------
5 files changed, 24 insertions(+), 21 deletions(-)
diff --git a/src/tools/clippy/tests/ui/erasing_op.rs b/src/tools/clippy/tests/ui/erasing_op.rs
index ae2fad0086d..74985029e00 100644
--- a/src/tools/clippy/tests/ui/erasing_op.rs
+++ b/src/tools/clippy/tests/ui/erasing_op.rs
@@ -31,9 +31,7 @@ impl core::ops::Mul<i32> for Vec1 {
#[allow(clippy::no_effect)]
#[warn(clippy::erasing_op)]
-fn main() {
- let x: u8 = 0;
-
+fn test(x: u8) {
x * 0;
0 & x;
0 / x;
@@ -41,3 +39,7 @@ fn main() {
0 * Vec1 { x: 5 };
Vec1 { x: 5 } * 0;
}
+
+fn main() {
+ test(0)
+}
diff --git a/src/tools/clippy/tests/ui/erasing_op.stderr b/src/tools/clippy/tests/ui/erasing_op.stderr
index 165ed9bfe58..97941252355 100644
--- a/src/tools/clippy/tests/ui/erasing_op.stderr
+++ b/src/tools/clippy/tests/ui/erasing_op.stderr
@@ -1,5 +1,5 @@
error: this operation will always return zero. This is likely not the intended outcome
- --> $DIR/erasing_op.rs:37:5
+ --> $DIR/erasing_op.rs:35:5
|
LL | x * 0;
| ^^^^^
@@ -7,25 +7,25 @@ LL | x * 0;
= note: `-D clippy::erasing-op` implied by `-D warnings`
error: this operation will always return zero. This is likely not the intended outcome
- --> $DIR/erasing_op.rs:38:5
+ --> $DIR/erasing_op.rs:36:5
|
LL | 0 & x;
| ^^^^^
error: this operation will always return zero. This is likely not the intended outcome
- --> $DIR/erasing_op.rs:39:5
+ --> $DIR/erasing_op.rs:37:5
|
LL | 0 / x;
| ^^^^^
error: this operation will always return zero. This is likely not the intended outcome
- --> $DIR/erasing_op.rs:41:5
+ --> $DIR/erasing_op.rs:39:5
|
LL | 0 * Vec1 { x: 5 };
| ^^^^^^^^^^^^^^^^^
error: this operation will always return zero. This is likely not the intended outcome
- --> $DIR/erasing_op.rs:42:5
+ --> $DIR/erasing_op.rs:40:5
|
LL | Vec1 { x: 5 } * 0;
| ^^^^^^^^^^^^^^^^^
diff --git a/src/tools/clippy/tests/ui/integer_arithmetic.rs b/src/tools/clippy/tests/ui/integer_arithmetic.rs
index 67f24b4548a..8dfdee662b9 100644
--- a/src/tools/clippy/tests/ui/integer_arithmetic.rs
+++ b/src/tools/clippy/tests/ui/integer_arithmetic.rs
@@ -4,7 +4,7 @@
#[rustfmt::skip]
fn main() {
let mut i = 1i32;
- let mut var1 = 0i32;
+ let mut var1 = 13i32;
let mut var2 = -1i32;
1 + i;
i * 2;
diff --git a/src/tools/clippy/tests/ui/overflow_check_conditional.rs b/src/tools/clippy/tests/ui/overflow_check_conditional.rs
index 5db75f5291b..e1e30114081 100644
--- a/src/tools/clippy/tests/ui/overflow_check_conditional.rs
+++ b/src/tools/clippy/tests/ui/overflow_check_conditional.rs
@@ -1,9 +1,6 @@
#![warn(clippy::overflow_check_conditional)]
-fn main() {
- let a: u32 = 1;
- let b: u32 = 2;
- let c: u32 = 3;
+fn test(a: u32, b: u32, c: u32) {
if a + b < a {}
if a > a + b {}
if a + b < b {}
@@ -23,3 +20,7 @@ fn main() {
if i > i + j {}
if i - j < i {}
}
+
+fn main() {
+ test(1, 2, 3)
+}
diff --git a/src/tools/clippy/tests/ui/overflow_check_conditional.stderr b/src/tools/clippy/tests/ui/overflow_check_conditional.stderr
index 1b8b146b60a..92d1d8ef911 100644
--- a/src/tools/clippy/tests/ui/overflow_check_conditional.stderr
+++ b/src/tools/clippy/tests/ui/overflow_check_conditional.stderr
@@ -1,5 +1,5 @@
error: you are trying to use classic C overflow conditions that will fail in Rust
- --> $DIR/overflow_check_conditional.rs:7:8
+ --> $DIR/overflow_check_conditional.rs:4:8
|
LL | if a + b < a {}
| ^^^^^^^^^
@@ -7,43 +7,43 @@ LL | if a + b < a {}
= note: `-D clippy::overflow-check-conditional` implied by `-D warnings`
error: you are trying to use classic C overflow conditions that will fail in Rust
- --> $DIR/overflow_check_conditional.rs:8:8
+ --> $DIR/overflow_check_conditional.rs:5:8
|
LL | if a > a + b {}
| ^^^^^^^^^
error: you are trying to use classic C overflow conditions that will fail in Rust
- --> $DIR/overflow_check_conditional.rs:9:8
+ --> $DIR/overflow_check_conditional.rs:6:8
|
LL | if a + b < b {}
| ^^^^^^^^^
error: you are trying to use classic C overflow conditions that will fail in Rust
- --> $DIR/overflow_check_conditional.rs:10:8
+ --> $DIR/overflow_check_conditional.rs:7:8
|
LL | if b > a + b {}
| ^^^^^^^^^
error: you are trying to use classic C underflow conditions that will fail in Rust
- --> $DIR/overflow_check_conditional.rs:11:8
+ --> $DIR/overflow_check_conditional.rs:8:8
|
LL | if a - b > b {}
| ^^^^^^^^^
error: you are trying to use classic C underflow conditions that will fail in Rust
- --> $DIR/overflow_check_conditional.rs:12:8
+ --> $DIR/overflow_check_conditional.rs:9:8
|
LL | if b < a - b {}
| ^^^^^^^^^
error: you are trying to use classic C underflow conditions that will fail in Rust
- --> $DIR/overflow_check_conditional.rs:13:8
+ --> $DIR/overflow_check_conditional.rs:10:8
|
LL | if a - b > a {}
| ^^^^^^^^^
error: you are trying to use classic C underflow conditions that will fail in Rust
- --> $DIR/overflow_check_conditional.rs:14:8
+ --> $DIR/overflow_check_conditional.rs:11:8
|
LL | if a < a - b {}
| ^^^^^^^^^
From d94ec3091ecc663ef30f288ac859694e2512f31b Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Wed, 8 Mar 2023 08:44:35 +0000
Subject: [PATCH 12/13] Bless 32bit.
---
tests/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tests/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff b/tests/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff
index b9a10704be0..6d8738aa61a 100644
--- a/tests/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff
+++ b/tests/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff
@@ -22,7 +22,7 @@
- switchInt(move _4) -> [1: bb1, otherwise: bb3]; // scope 2 at $DIR/discriminant.rs:+1:21: +1:31
+ _3 = const Option::<bool>::Some(true); // scope 2 at $DIR/discriminant.rs:+1:34: +1:44
+ // mir::Constant
-+ // + span: $DIR/discriminant.rs:12:34: 12:44
++ // + span: no-location
+ // + literal: Const { ty: Option<bool>, val: Value(Scalar(0x01)) }
+ _4 = const 1_isize; // scope 2 at $DIR/discriminant.rs:+1:21: +1:31
+ switchInt(const 1_isize) -> [1: bb1, otherwise: bb3]; // scope 2 at $DIR/discriminant.rs:+1:21: +1:31
From 8179b2e5f8ab3524aa7860d8b34897949dde4b65 Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Wed, 8 Mar 2023 14:41:37 +0000
Subject: [PATCH 13/13] Remove useless parameter to operand_from_scalar.
---
.../rustc_mir_transform/src/const_prop.rs | 19 +++++--------------
1 file changed, 5 insertions(+), 14 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 334dd90d4ae..6c5202549ea 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -458,11 +458,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
scalar,
)) = *value
{
- *operand = self.operand_from_scalar(
- scalar,
- value.layout.ty,
- DUMMY_SP,
- );
+ *operand = self.operand_from_scalar(scalar, value.layout.ty);
}
}
}
@@ -587,9 +583,9 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
}
/// Creates a new `Operand::Constant` from a `Scalar` value
- fn operand_from_scalar(&self, scalar: Scalar, ty: Ty<'tcx>, span: Span) -> Operand<'tcx> {
+ fn operand_from_scalar(&self, scalar: Scalar, ty: Ty<'tcx>) -> Operand<'tcx> {
Operand::Constant(Box::new(Constant {
- span,
+ span: DUMMY_SP,
user_ty: None,
literal: ConstantKind::from_scalar(self.tcx, scalar, ty),
}))
@@ -634,8 +630,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
if let Some(Right(imm)) = imm {
match *imm {
interpret::Immediate::Scalar(scalar) => {
- *rval =
- Rvalue::Use(self.operand_from_scalar(scalar, value.layout.ty, DUMMY_SP));
+ *rval = Rvalue::Use(self.operand_from_scalar(scalar, value.layout.ty));
}
Immediate::ScalarPair(..) => {
// Found a value represented as a pair. For now only do const-prop if the type
@@ -933,11 +928,7 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
&& self.should_const_prop(value)
{
trace!("assertion on {:?} should be {:?}", value, expected);
- *cond = self.operand_from_scalar(
- value_const,
- self.tcx.types.bool,
- DUMMY_SP,
- );
+ *cond = self.operand_from_scalar(value_const, self.tcx.types.bool);
}
}
TerminatorKind::SwitchInt { ref mut discr, .. } => {