[llvm] [MacroFusion] Support commutable instructions (PR #82751)

[Wang Pengcheng via llvm-commits]

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@@ -208,8 +208,19 @@ void MacroFusionPredicatorEmitter::emitBothPredicate(Record *Predicate,
                  << ").isReg() &&\n";
     OS.indent(2) << "      FirstMI->getOperand(" << FirstOpIdx
                  << ").getReg() == SecondMI.getOperand(" << SecondOpIdx
-                 << ").getReg()))\n";
-    OS.indent(2) << "  return false;\n";
+                 << ").getReg())) {\n";
+
+    OS.indent(4) << "if (!SecondMI.getDesc().isCommutable())\n";
+    OS.indent(4) << "  return false;\n";
+
+    OS.indent(4) << "unsigned SrcOpIdx1 = " << SecondOpIdx
+                 << ", SrcOpIdx2 = TargetInstrInfo::CommuteAnyOperandIndex;\n";
+    OS.indent(4)
+        << "if (TII.findCommutedOpIndices(SecondMI, SrcOpIdx1, SrcOpIdx2))\n";
+    OS.indent(4) << "  if (!(FirstMI->getOperand(0).getReg() ==\n";
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wangpc-pp wrote:

Oops, it should be a typo. It should be `FirstMI->getOperand(FirstOpIdx).getReg()`。

https://github.com/llvm/llvm-project/pull/82751