Revert the part of 64623 that attempted to align the source in a

memcpy to match the alignment of the destination. It isn't necessary
for making loads and stores handled like the SSE loadu/storeu
intrinsics, and it was causing a performance regression in
MultiSource/Applications/JM/lencod.

The problem appears to have been a memcpy that copies from some
highly aligned array into an alloca; the alloca was then being
assigned a large alignment, which required codegen to perform
dynamic stack-pointer re-alignment, which forced the enclosing
function to have a frame pointer, which led to increased spilling.

llvm-svn: 65289

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index cfd1bac7ba8..2b18640f41a 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -9286,7 +9286,7 @@ unsigned InstCombiner::GetOrEnforceKnownAlignment(Value *V,
 
 Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) {
   unsigned DstAlign = GetOrEnforceKnownAlignment(MI->getOperand(1));
-  unsigned SrcAlign = GetOrEnforceKnownAlignment(MI->getOperand(2), DstAlign);
+  unsigned SrcAlign = GetOrEnforceKnownAlignment(MI->getOperand(2));
   unsigned MinAlign = std::min(DstAlign, SrcAlign);
   unsigned CopyAlign = MI->getAlignment()->getZExtValue();