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
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 07681d1..ba899bf 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -11943,9 +11943,11 @@
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 @@
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 @@
// 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);