[llvm] r214953 - [x86] Switch to a formulation of a for loop that is much more obviously

[Chandler Carruth]

Author: chandlerc
Date: Wed Aug  6 05:16:33 2014
New Revision: 214953

URL: http://llvm.org/viewvc/llvm-project?rev=214953&view=rev
Log:
[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).

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=214953&r1=214952&r2=214953&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Wed Aug  6 05:16:33 2014
@@ -7519,9 +7519,10 @@ static SDValue lowerV8I16SingleInputVect
     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);