[llvm] [AArch64][GlobalISel] Extend smaller than i32 gpr loads/stores in RegBankSelect. (PR #175810)

[David Green via llvm-commits]

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@@ -364,9 +364,33 @@ void AArch64RegisterBankInfo::applyMappingImpl(
   MachineRegisterInfo &MRI = OpdMapper.getMRI();
 
   switch (MI.getOpcode()) {
+  case TargetOpcode::G_STORE: {
+    Register Dst = MI.getOperand(0).getReg();
+    LLT Ty = MRI.getType(Dst);
+    if (MRI.getRegBank(Dst) == &AArch64::GPRRegBank && Ty.isScalar() &&
+        Ty.getSizeInBits() < 32) {
+      Builder.setInsertPt(*MI.getParent(), MI.getIterator());
+      auto Ext = Builder.buildAnyExt(LLT::scalar(32), Dst);
+      MI.getOperand(0).setReg(Ext.getReg(0));
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davemgreen wrote:

Hi - Sorry I missed that point. I don't see a change observer in RegBankSelect or AArch64RegisterBankInfo. (There is one in AMDGPURegBankSelect).

https://github.com/llvm/llvm-project/pull/175810