From: Chandler Carruth <chandlerc@gmail.com>
Date: Wed, 6 Aug 2014 10:16:33 +0000 (+0000)
Subject: [x86] Switch to a formulation of a for loop that is much more obviously
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=346b68772b99011568cb82beb27bbc548a99d0ad;p=oota-llvm.git

[x86] Switch to a formulation of a for loop that is much more obviously
not corrupting the mask by mutating it more times than intended. No
functionality changed (the results were non-overlapping so the old
version "worked" but was non-obvious).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214953 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 18b3bb25cae..7bf58e20dac 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -7519,9 +7519,10 @@ static SDValue lowerV8I16SingleInputVectorShuffle(
     int FreeDWord = (PSHUFDMask[DestOffset / 2] == -1 ? 0 : 1) + DestOffset / 2;
     assert(PSHUFDMask[FreeDWord] == -1 && "DWord not free");
     PSHUFDMask[FreeDWord] = IncomingInputs[0] / 2;
-    for (int Input : IncomingInputs)
-      std::replace(HalfMask.begin(), HalfMask.end(), Input,
-                   FreeDWord * 2 + Input % 2);
+    for (int &M : HalfMask)
+      for (int Input : IncomingInputs)
+        if (M == Input)
+          M = FreeDWord * 2 + Input % 2;
   };
   moveInputsToRightHalf(HToLInputs, LToLInputs, PSHUFHMask, LoMask,
                         /*SourceOffset*/ 4, /*DestOffset*/ 0);