[llvm] [PowerPC] Fix shuffle combine with undef elements (PR #77787)

[Nikita Popov via llvm-commits]

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@@ -15428,15 +15428,15 @@ SDValue PPCTargetLowering::combineVectorShuffle(ShuffleVectorSDNode *SVN,
     // vector_shuffle<0,16,1,17,2,18,3,19,4,20,5,21,6,22,7,23> t1, <zero>
     if (Mask[0] < NumElts)
       for (int i = 1, e = Mask.size(); i < e; i += 2) {
-        if (ShuffV[i] < 0)
+        if (ShuffV[i] < 0 || ShuffV[i - 1] < 0)
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nikic wrote:

Done!

https://github.com/llvm/llvm-project/pull/77787