[llvm-branch-commits] [llvm] [AArch64][ISel] Select constructive EXT_ZZZI pseudo instruction (PR #152554)

[Gaëtan Bossu via llvm-branch-commits]

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@@ -86,6 +83,13 @@ bool AArch64PostCoalescer::runOnMachineFunction(MachineFunction &MF) {
         Changed = true;
         break;
       }
+      case AArch64::EXT_ZZZI:
+        Register DstReg = MI.getOperand(0).getReg();
+        Register SrcReg1 = MI.getOperand(1).getReg();
+        if (SrcReg1 != DstReg) {
+          MRI->setRegAllocationHint(DstReg, 0, SrcReg1);
+        }
+        break;
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gbossu wrote:

Note that this commit is really just a WIP to show we can slightly improve codegen with some hints. I'm not sure it should remain in that PR.

https://github.com/llvm/llvm-project/pull/152554