rust/tests/mir-opt/simplify_dead_blocks.rs

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//@ test-mir-pass: SimplifyCfg-after-unreachable-enum-branching
#![feature(custom_mir, core_intrinsics)]
#![crate_type = "lib"]
use std::intrinsics::mir::*;
// Check that we correctly cleaned up the dead BB.
// EMIT_MIR simplify_dead_blocks.assert_nonzero_nonmax.SimplifyCfg-after-unreachable-enum-branching.diff
#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
pub unsafe fn assert_nonzero_nonmax(x: u8) -> u8 {
// CHECK-LABEL: fn assert_nonzero_nonmax(
// CHECK: bb0: {
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// CHECK-NEXT: switchInt(copy {{_[0-9]+}}) -> [0: [[unreachable:bb.*]], 1: [[retblock2:bb.*]], 255: [[unreachable:bb.*]], otherwise: [[retblock:bb.*]]];
// CHECK-NEXT: }
// CHECK-NOT: _0 = const 1_u8;
// CHECK: [[retblock2]]: {
// CHECK-NEXT: _0 = const 2_u8;
// CHECK-NEXT: return;
// CHECK-NEXT: }
// CHECK: [[unreachable]]: {
// CHECK-NEXT: unreachable;
// CHECK-NEXT: }
// CHECK: [[retblock]]: {
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// CHECK-NEXT: _0 = copy _1;
// CHECK-NEXT: return;
// CHECK-NEXT: }
Reformat `mir!` macro invocations to use braces. The `mir!` macro has multiple parts: - An optional return type annotation. - A sequence of zero or more local declarations. - A mandatory starting anonymous basic block, which is brace-delimited. - A sequence of zero of more additional named basic blocks. Some `mir!` invocations use braces with a "block" style, like so: ``` mir! { let _unit: (); { let non_copy = S(42); let ptr = std::ptr::addr_of_mut!(non_copy); // Inside `callee`, the first argument and `*ptr` are basically // aliasing places! Call(_unit = callee(Move(*ptr), ptr), ReturnTo(after_call), UnwindContinue()) } after_call = { Return() } } ``` Some invocations use parens with a "block" style, like so: ``` mir!( let x: [i32; 2]; let one: i32; { x = [42, 43]; one = 1; x = [one, 2]; RET = Move(x); Return() } ) ``` And some invocations uses parens with a "tighter" style, like so: ``` mir!({ SetDiscriminant(*b, 0); Return() }) ``` This last style is generally used for cases where just the mandatory starting basic block is present. Its braces are placed next to the parens. This commit changes all `mir!` invocations to use braces with a "block" style. Why? - Consistency is good. - The contents of the invocation is a block of code, so it's odd to use parens. They are more normally used for function-like macros. - Most importantly, the next commit will enable rustfmt for `tests/mir-opt/`. rustfmt is more aggressive about formatting macros that use parens than macros that use braces. Without this commit's changes, rustfmt would break a couple of `mir!` macro invocations that use braces within `tests/mir-opt` by inserting an extraneous comma. E.g.: ``` mir!(type RET = (i32, bool);, { // extraneous comma after ';' RET.0 = 1; RET.1 = true; Return() }) ``` Switching those `mir!` invocations to use braces avoids that problem, resulting in this, which is nicer to read as well as being valid syntax: ``` mir! { type RET = (i32, bool); { RET.0 = 1; RET.1 = true; Return() } } ```
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mir! {
{
match x {
0 => unreachable,
1 => retblock2,
u8::MAX => unreachable,
_ => retblock,
}
}
deadRetblock1 = {
RET = 1;
Return()
}
retblock2 = {
RET = 2;
Return()
}
unreachable = {
Unreachable()
}
retblock = {
RET = x;
Return()
}
Reformat `mir!` macro invocations to use braces. The `mir!` macro has multiple parts: - An optional return type annotation. - A sequence of zero or more local declarations. - A mandatory starting anonymous basic block, which is brace-delimited. - A sequence of zero of more additional named basic blocks. Some `mir!` invocations use braces with a "block" style, like so: ``` mir! { let _unit: (); { let non_copy = S(42); let ptr = std::ptr::addr_of_mut!(non_copy); // Inside `callee`, the first argument and `*ptr` are basically // aliasing places! Call(_unit = callee(Move(*ptr), ptr), ReturnTo(after_call), UnwindContinue()) } after_call = { Return() } } ``` Some invocations use parens with a "block" style, like so: ``` mir!( let x: [i32; 2]; let one: i32; { x = [42, 43]; one = 1; x = [one, 2]; RET = Move(x); Return() } ) ``` And some invocations uses parens with a "tighter" style, like so: ``` mir!({ SetDiscriminant(*b, 0); Return() }) ``` This last style is generally used for cases where just the mandatory starting basic block is present. Its braces are placed next to the parens. This commit changes all `mir!` invocations to use braces with a "block" style. Why? - Consistency is good. - The contents of the invocation is a block of code, so it's odd to use parens. They are more normally used for function-like macros. - Most importantly, the next commit will enable rustfmt for `tests/mir-opt/`. rustfmt is more aggressive about formatting macros that use parens than macros that use braces. Without this commit's changes, rustfmt would break a couple of `mir!` macro invocations that use braces within `tests/mir-opt` by inserting an extraneous comma. E.g.: ``` mir!(type RET = (i32, bool);, { // extraneous comma after ';' RET.0 = 1; RET.1 = true; Return() }) ``` Switching those `mir!` invocations to use braces avoids that problem, resulting in this, which is nicer to read as well as being valid syntax: ``` mir! { type RET = (i32, bool); { RET.0 = 1; RET.1 = true; Return() } } ```
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}
}