Check alignment of loads when deciding whether it is safe to execute them

unconditionally.  Besides checking the offset, also check that the underlying
object is aligned as much as the load itself.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94875 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 4 insertions, 2 deletions

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 9c18452..6e70952 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -1651,7 +1651,8 @@ bool GVN::processNonLocalLoad(LoadInst *LI,
   if (!allSingleSucc &&
       // FIXME: REEVALUTE THIS.
       !isSafeToLoadUnconditionally(LoadPtr,
-                                   UnavailablePred->getTerminator(), TD)) {
+                                   UnavailablePred->getTerminator(),
+                                   LI->getAlignment(), TD)) {
     assert(NewInsts.empty() && "Should not have inserted instructions");
     return false;
   }
diff --git a/lib/Transforms/Scalar/TailRecursionElimination.cpp b/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 4119cb9..162d902 100644
--- a/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -211,7 +211,8 @@ bool TailCallElim::CanMoveAboveCall(Instruction *I, CallInst *CI) {
       // FIXME: Writes to memory only matter if they may alias the pointer
       // being loaded from.
       if (CI->mayWriteToMemory() ||
-          !isSafeToLoadUnconditionally(L->getPointerOperand(), L))
+          !isSafeToLoadUnconditionally(L->getPointerOperand(), L,
+                                       L->getAlignment()))
         return false;
     }
   }