[llvm] [AArch64][GlobalISel] Add push_mul_through_s/zext (PR #141551)

[Cullen Rhodes via llvm-commits]

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@@ -246,31 +247,57 @@ bool matchExtAddvToUdotAddv(MachineInstr &MI, MachineRegisterInfo &MRI,
   if (DstTy.getScalarSizeInBits() != 32 || MidTy.getScalarSizeInBits() != 32)
     return false;
 
-  LLT SrcTy;
-  auto I1Opc = I1->getOpcode();
-  if (I1Opc == TargetOpcode::G_MUL) {
+  // Detect mul(ext, ext) with symetric ext's. If I1Opc is G_ZEXT or G_SEXT then
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c-rhodes wrote:

```suggestion
  // Detect mul(ext, ext) with symmetric ext's. If I1Opc is G_ZEXT or G_SEXT then
```

https://github.com/llvm/llvm-project/pull/141551