From d2dd0fac483c1ac2dba5c19626669b86256073bb Mon Sep 17 00:00:00 2001
From: Michael Liao <michael.hliao@gmail.com>
Date: Sat, 28 Mar 2020 01:40:31 -0400
Subject: [PATCH] Fix `-Wsign-compare` warning. NFC.

---
 llvm/lib/Target/X86/X86PartialReduction.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Target/X86/X86PartialReduction.cpp b/llvm/lib/Target/X86/X86PartialReduction.cpp
index 4cd231de3440..daa293d1e740 100644
--- a/llvm/lib/Target/X86/X86PartialReduction.cpp
+++ b/llvm/lib/Target/X86/X86PartialReduction.cpp
@@ -372,7 +372,7 @@ bool X86PartialReduction::trySADReplacement(Value *Op, BinaryOperator *Add) {
   unsigned Stages = Log2_32(NumSplits);
   for (unsigned s = Stages; s > 0; --s) {
     unsigned NumConcatElts = Ops[0]->getType()->getVectorNumElements() * 2;
-    for (unsigned i = 0; i != 1 << (s - 1); ++i) {
+    for (unsigned i = 0; i != 1U << (s - 1); ++i) {
       SmallVector<uint32_t, 64> ConcatMask(NumConcatElts);
       std::iota(ConcatMask.begin(), ConcatMask.end(), 0);
       Ops[i] = Builder.CreateShuffleVector(Ops[i*2], Ops[i*2+1], ConcatMask);