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[Sink] Really really fix predicate in legality check

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LoadInst isn't enough; we need to include intrinsics that perform loads too.

All side-effecting intrinsics and such are already covered by the isSafe
check, so we just need to care about things that read from memory.

D41960, originally from D33179.

llvm-svn: 322311
This commit is contained in:
Fiona Glaser 2018-01-11 21:28:57 +00:00
parent f07600c58f
commit c5f9051b0c
2 changed files with 11 additions and 3 deletions
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2
lib/Transforms/Scalar/Sink.cpp
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@ -114,7 +114,7 @@ static bool IsAcceptableTarget(Instruction *Inst, BasicBlock *SuccToSinkTo,
if (SuccToSinkTo->getUniquePredecessor() != Inst->getParent()) {
// We cannot sink a load across a critical edge - there may be stores in
// other code paths.
if (isa<LoadInst>(Inst))
if (Inst->mayReadFromMemory())
return false;
// We don't want to sink across a critical edge if we don't dominate the

12
test/Transforms/Sink/badloadsink.ll
View File

@ -1,18 +1,26 @@
; RUN: opt < %s -basicaa -sink -S | FileCheck %s
declare void @foo(i64 *)
define i64 @sinkload(i1 %cmp) {
declare i8* @llvm.load.relative.i32(i8* %ptr, i32 %offset) argmemonly nounwind readonly
define i64 @sinkload(i1 %cmp, i8* %ptr, i32 %off) {
; CHECK-LABEL: @sinkload
top:
%a = alloca i64
; CHECK: call void @foo(i64* %a)
; CHECK-NEXT: %x = load i64, i64* %a
; CHECK-NEXT: %y = call i8* @llvm.load.relative.i32(i8* %ptr, i32 %off)
call void @foo(i64* %a)
%x = load i64, i64* %a
%y = call i8* @llvm.load.relative.i32(i8* %ptr, i32 %off)
br i1 %cmp, label %A, label %B
A:
store i64 0, i64 *%a
store i8 0, i8 *%ptr
br label %B
B:
; CHECK-NOT: load i64, i64 *%a
ret i64 %x
; CHECK-NOT: call i8* @llvm.load.relative(i8* %ptr, i32 off)
%y2 = ptrtoint i8* %y to i64
%retval = add i64 %y2, %x
ret i64 %retval
}