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my previous patch would cause us to start deleting some volatile 

stores, fix and add a testcase.

llvm-svn: 120363
This commit is contained in:
Chris Lattner 2010-11-30 00:12:39 +00:00
parent 49408cef39
commit c3c754f750
2 changed files with 21 additions and 1 deletions
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2
llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
View File

@ -222,7 +222,7 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
if (LoadInst *DepLoad = dyn_cast<LoadInst>(InstDep.getInst())) {
if (SI->getPointerOperand() == DepLoad->getPointerOperand() &&
SI->getOperand(0) == DepLoad) {
SI->getOperand(0) == DepLoad && !SI->isVolatile()) {
// DeleteDeadInstruction can delete the current instruction. Save BBI
// in case we need it.
WeakVH NextInst(BBI);

20
llvm/test/Transforms/DeadStoreElimination/simple.ll
View File

@ -34,3 +34,23 @@ define i32 @test3(i32* %g_addr) nounwind {
%tmp3 = load i32* @g, align 4
ret i32 %tmp3
}
define void @test4(i32* %Q) {
%a = load i32* %Q
volatile store i32 %a, i32* %Q
ret void
; CHECK: @test4
; CHECK-NEXT: load i32
; CHECK-NEXT: volatile store
; CHECK-NEXT: ret void
}
define void @test5(i32* %Q) {
%a = volatile load i32* %Q
store i32 %a, i32* %Q
ret void
; CHECK: @test5
; CHECK-NEXT: volatile load
; CHECK-NEXT: ret void
}