fix instcombine to only do store sinking when the alignments

of the two loads agree.  Propagate that onto the new store.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85772 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2009-11-02 02:06:37 +00:00
parent f013eea972
commit 7ebbabf500
2 changed files with 26 additions and 4 deletions

View File

@ -11943,9 +11943,11 @@ bool InstCombiner::SimplifyStoreAtEndOfBlock(StoreInst &SI) {
return false;
--BBI;
}
// If this isn't a store, or isn't a store to the same location, bail out.
// If this isn't a store, isn't a store to the same location, or if the
// alignments differ, bail out.
OtherStore = dyn_cast<StoreInst>(BBI);
if (!OtherStore || OtherStore->getOperand(1) != SI.getOperand(1))
if (!OtherStore || OtherStore->getOperand(1) != SI.getOperand(1) ||
OtherStore->getAlignment() != SI.getAlignment())
return false;
} else {
// Otherwise, the other block ended with a conditional branch. If one of the
@ -11960,7 +11962,8 @@ bool InstCombiner::SimplifyStoreAtEndOfBlock(StoreInst &SI) {
for (;; --BBI) {
// Check to see if we find the matching store.
if ((OtherStore = dyn_cast<StoreInst>(BBI))) {
if (OtherStore->getOperand(1) != SI.getOperand(1))
if (OtherStore->getOperand(1) != SI.getOperand(1) ||
OtherStore->getAlignment() != SI.getAlignment())
return false;
break;
}
@ -11995,7 +11998,8 @@ bool InstCombiner::SimplifyStoreAtEndOfBlock(StoreInst &SI) {
// insert it.
BBI = DestBB->getFirstNonPHI();
InsertNewInstBefore(new StoreInst(MergedVal, SI.getOperand(1),
OtherStore->isVolatile()), *BBI);
OtherStore->isVolatile(),
SI.getAlignment()), *BBI);
// Nuke the old stores.
EraseInstFromFunction(SI);

View File

@ -64,3 +64,21 @@ Cont:
; CHECK-NEXT: ret i32 %storemerge
}
; "if then"
define void @test5(i1 %C, i32* %P) {
store i32 47, i32* %P, align 1
br i1 %C, label %Cond, label %Cont
Cond:
store i32 -987654321, i32* %P, align 1
br label %Cont
Cont:
ret void
; CHECK: @test5
; CHECK: Cont:
; CHECK-NEXT: %storemerge = phi i32
; CHECK-NEXT: store i32 %storemerge, i32* %P, align 1
; CHECK-NEXT: ret void
}