[llvm] [RISCV] Sources of vmerge shouldn't overlap V0 (PR #170070)

[Craig Topper via llvm-commits]

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@@ -387,23 +387,18 @@ bool RISCVVectorPeephole::convertAllOnesVMergeToVMv(MachineInstr &MI) const {
   return true;
 }
 
-bool RISCVVectorPeephole::isKnownSameDefs(Register A, Register B) const {
-  if (A.isPhysical() || B.isPhysical())
-    return false;
-
-  auto LookThruVirtRegCopies = [this](Register Reg) {
-    while (MachineInstr *Def = MRI->getUniqueVRegDef(Reg)) {
-      if (!Def->isFullCopy())
-        break;
-      Register Src = Def->getOperand(1).getReg();
-      if (!Src.isVirtual())
-        break;
-      Reg = Src;
-    }
-    return Reg;
-  };
-
-  return LookThruVirtRegCopies(A) == LookThruVirtRegCopies(B);
+// If \p Reg is defined by one or more COPYs of virtual registers, traverses
+/// the chain and returns the root non-COPY source.
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topperc wrote:

Mismatched `//` and `///`

https://github.com/llvm/llvm-project/pull/170070