[X86] Make memcmp vector lowering handle arbitrary expansions

Teach combineVectorSizedSetCCEquality() to handle arbitrary memcmp
expansions but do not change any default policy for now.

This also fixes a bug in the memcmp expansion itself when large
displacements are needed.

https://reviews.llvm.org/D69507

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/ExpandMemCmp.cpp b/llvm/lib/CodeGen/ExpandMemCmp.cpp
index 9916f2de041..0539db58a61 100644
--- a/llvm/lib/CodeGen/ExpandMemCmp.cpp
+++ b/llvm/lib/CodeGen/ExpandMemCmp.cpp
@@ -264,9 +264,9 @@ Value *MemCmpExpansion::getPtrToElementAtOffset(Value *Source,
                                                 uint64_t OffsetBytes) {
   if (OffsetBytes > 0) {
     auto *ByteType = Type::getInt8Ty(CI->getContext());
-    Source = Builder.CreateGEP(
+    Source = Builder.CreateConstGEP1_64(
         ByteType, Builder.CreateBitCast(Source, ByteType->getPointerTo()),
-        ConstantInt::get(ByteType, OffsetBytes));
+        OffsetBytes);
   }
   return Builder.CreateBitCast(Source, LoadSizeType->getPointerTo());
 }