[PATCH] D54267: [X86][SSE] Add lowerVectorShuffleAsByteRotateAndPermute (PR39387)

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: lib/Target/X86/X86ISelLowering.cpp:10495
+  // can be widened.
+  if (!(0 <= Range1.first && Range1.second < NumElts &&
+        Range1.first <= Range1.second) ||
----------------
Should this be NumLaneElts instead of NumElts?


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Comment at: lib/Target/X86/X86ISelLowering.cpp:10496
+  if (!(0 <= Range1.first && Range1.second < NumElts &&
+        Range1.first <= Range1.second) ||
+      !(0 <= Range2.first && Range2.second < NumElts &&
----------------
If the min/max is inside the lane, isn't Range1.first always less than or equal to Range1.second? And isn't Range1.first always less than or equal to Range1.second unless the input is unused by the shuffle? Which would mean the input is undef?


Repository:
  rL LLVM

https://reviews.llvm.org/D54267