[llvm] [GlobalIsel] combine ext of trunc with flags (PR #87115)

[Matt Arsenault via llvm-commits]

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@@ -7138,3 +7138,69 @@ bool CombinerHelper::matchAddOverflow(MachineInstr &MI, BuildFnTy &MatchInfo) {
 
   return false;
 }
+
+void CombinerHelper::applyBuildFnMO(const MachineOperand &MO,
+                                    BuildFnTy &MatchInfo) {
+  MachineInstr *Root = getDefIgnoringCopies(MO.getReg(), MRI);
+  Builder.setInstrAndDebugLoc(*Root);
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arsenm wrote:

This should be unnecessary since 360f7f5674c4ddef006d233ef7259f8fe07ae81b

https://github.com/llvm/llvm-project/pull/87115