Count implicit defs as well as explicit ones in the GlobalISel TableGen emitter.

NumDefs only counts the number of registers in (outs), not any
implicit defs specified with Defs = [...]

Author: JL2210

llvm/utils/TableGen/GlobalISelEmitter.cpp

@@ -2023,7 +2023,10 @@ Expected<RuleMatcher> GlobalISelEmitter::runOnPattern(const PatternToMatch &P) {
   auto &DstI = Target.getInstruction(DstOp);
   StringRef DstIName = DstI.TheDef->getName();
 
-  unsigned DstNumDefs = DstI.Operands.NumDefs,
+  // Count both implicit and explicit defs in the dst instruction.
+  // This avoids errors importing patterns that have inherent implicit defs.
+  unsigned DstExpDefs = DstI.Operands.NumDefs,
+           DstNumDefs = DstI.ImplicitDefs.size() + DstExpDefs,
            SrcNumDefs = Src.getExtTypes().size();
   if (DstNumDefs < SrcNumDefs) {
     if (DstNumDefs != 0)
@@ -2045,7 +2048,7 @@ Expected<RuleMatcher> GlobalISelEmitter::runOnPattern(const PatternToMatch &P) {
   // The root of the match also has constraints on the register bank so that it
   // matches the result instruction.
   unsigned OpIdx = 0;
-  unsigned N = std::min(DstNumDefs, SrcNumDefs);
+  unsigned N = std::min(DstExpDefs, SrcNumDefs);
   for (unsigned I = 0; I < N; ++I) {
     const TypeSetByHwMode &VTy = Src.getExtType(I);