[llvm] [RISCV] Check for COPY_TO_REGCLASS in usesAllOnesMask (PR #67037)

[Philip Reames via llvm-commits]

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@@ -3188,6 +3188,12 @@ static bool usesAllOnesMask(SDValue MaskOp, SDValue GlueOp) {
   // Check the instruction defining V0; it needs to be a VMSET pseudo.
   SDValue MaskSetter = Glued->getOperand(2);
 
+  // Sometimes the VMSET is wrapped in a COPY_TO_REGCLASS node, e.g. if the mask
+  // was extracted from a larger register.
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preames wrote:

Ok, yeah, that fits more.  We've got two types of different sizes, but they share the same register class.  Ok, understood.

https://github.com/llvm/llvm-project/pull/67037