[llvm] a5bdada - [X86][AVX] lowerShuffleAsLanePermuteAndShuffle - consistently normalize multi-input shuffle elements

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2020-01-10T17:21:20Z
New Revision: a5bdada09defc15d2b009314306f4fcb8fa8458d

URL: https://github.com/llvm/llvm-project/commit/a5bdada09defc15d2b009314306f4fcb8fa8458d
DIFF: https://github.com/llvm/llvm-project/commit/a5bdada09defc15d2b009314306f4fcb8fa8458d.diff

LOG: [X86][AVX] lowerShuffleAsLanePermuteAndShuffle - consistently normalize multi-input shuffle elements

We only use lowerShuffleAsLanePermuteAndShuffle for unary shuffles at the moment, but we should consistently handle lane index calculations for multiple inputs in both the AVX1 and AVX2 paths.

Minor (almost NFC) tidyup as I'm hoping to use lowerShuffleAsLanePermuteAndShuffle for binary shuffles soon.

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 93ef3a02c2d5..7efb3059b391 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -14971,7 +14971,7 @@ static SDValue lowerShuffleAsLanePermuteAndShuffle(
   if (!Subtarget.hasAVX2()) {
     bool LaneCrossing[2] = {false, false};
     for (int i = 0; i < Size; ++i)
-      if (Mask[i] >= 0 && (Mask[i] % Size) / LaneSize != i / LaneSize)
+      if (Mask[i] >= 0 && ((Mask[i] % Size) / LaneSize) != (i / LaneSize))
         LaneCrossing[(Mask[i] % Size) / LaneSize] = true;
     if (!LaneCrossing[0] || !LaneCrossing[1])
       return splitAndLowerShuffle(DL, VT, V1, V2, Mask, DAG);
@@ -14979,7 +14979,7 @@ static SDValue lowerShuffleAsLanePermuteAndShuffle(
     bool LaneUsed[2] = {false, false};
     for (int i = 0; i < Size; ++i)
       if (Mask[i] >= 0)
-        LaneUsed[(Mask[i] / LaneSize)] = true;
+        LaneUsed[(Mask[i] % Size) / LaneSize] = true;
     if (!LaneUsed[0] || !LaneUsed[1])
       return splitAndLowerShuffle(DL, VT, V1, V2, Mask, DAG);
   }