Don't special case constant operands when lowering intrinsics

This commit is contained in:
Tomasz Miąsko 2020-11-16 00:00:00 +00:00
parent 603ab5bd6e
commit 2b7ffecee0
3 changed files with 42 additions and 8 deletions

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@ -11,15 +11,11 @@ pub struct LowerIntrinsics;
impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
for block in body.basic_blocks_mut() {
let (basic_blocks, local_decls) = body.basic_blocks_and_local_decls_mut();
for block in basic_blocks {
let terminator = block.terminator.as_mut().unwrap();
if let TerminatorKind::Call {
func: Operand::Constant(box Constant { literal: ty::Const { ty: func_ty, .. }, .. }),
args,
destination,
..
} = &mut terminator.kind
{
if let TerminatorKind::Call { func, args, destination, .. } = &mut terminator.kind {
let func_ty = func.ty(local_decls, tcx);
let (intrinsic_name, substs) = match resolve_rust_intrinsic(tcx, func_ty) {
None => continue,
Some(it) => it,

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@ -0,0 +1,31 @@
- // MIR for `non_const` before LowerIntrinsics
+ // MIR for `non_const` after LowerIntrinsics
fn non_const() -> usize {
let mut _0: usize; // return place in scope 0 at $DIR/lower_intrinsics.rs:55:26: 55:31
let _1: extern "rust-intrinsic" fn() -> usize {std::intrinsics::size_of::<T>}; // in scope 0 at $DIR/lower_intrinsics.rs:57:9: 57:18
let mut _2: extern "rust-intrinsic" fn() -> usize {std::intrinsics::size_of::<T>}; // in scope 0 at $DIR/lower_intrinsics.rs:58:5: 58:14
scope 1 {
debug size_of_t => _1; // in scope 1 at $DIR/lower_intrinsics.rs:57:9: 57:18
}
bb0: {
StorageLive(_1); // scope 0 at $DIR/lower_intrinsics.rs:57:9: 57:18
_1 = std::intrinsics::size_of::<T>; // scope 0 at $DIR/lower_intrinsics.rs:57:21: 57:51
// mir::Constant
// + span: $DIR/lower_intrinsics.rs:57:21: 57:51
// + literal: Const { ty: extern "rust-intrinsic" fn() -> usize {std::intrinsics::size_of::<T>}, val: Value(Scalar(<ZST>)) }
StorageLive(_2); // scope 1 at $DIR/lower_intrinsics.rs:58:5: 58:14
_2 = _1; // scope 1 at $DIR/lower_intrinsics.rs:58:5: 58:14
- _0 = move _2() -> bb1; // scope 1 at $DIR/lower_intrinsics.rs:58:5: 58:16
+ _0 = SizeOf(T); // scope 1 at $DIR/lower_intrinsics.rs:58:5: 58:16
+ goto -> bb1; // scope 1 at $DIR/lower_intrinsics.rs:58:5: 58:16
}
bb1: {
StorageDead(_2); // scope 1 at $DIR/lower_intrinsics.rs:58:15: 58:16
StorageDead(_1); // scope 0 at $DIR/lower_intrinsics.rs:59:1: 59:2
return; // scope 0 at $DIR/lower_intrinsics.rs:59:2: 59:2
}
}

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@ -50,3 +50,10 @@ pub fn f_zst<T>(t: T) {
#[inline(never)]
pub fn f_non_zst<T>(t: T) {}
// EMIT_MIR lower_intrinsics.non_const.LowerIntrinsics.diff
pub fn non_const<T>() -> usize {
// Check that lowering works with non-const operand as a func.
let size_of_t = core::intrinsics::size_of::<T>;
size_of_t()
}