From aaa7f499c1a2d46491a98d978ef45b0a06d73d31 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Thu, 19 May 2011 18:18:39 +0000
Subject: [PATCH] Add comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131659 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/InstCombine/InstCombineCalls.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 4b8a67d94d4..243937705ac 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -597,6 +597,7 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
   case Intrinsic::x86_sse41_pmovzxbw:
   case Intrinsic::x86_sse41_pmovzxwd:
   case Intrinsic::x86_sse41_pmovzxdq: {
+    // pmov{s|z}x ignores the upper half of their input vectors.
     unsigned VWidth =
       cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements();
     unsigned LowHalfElts = VWidth / 2;
-- 
2.34.1