[PATCH] D108137: [AArch64][Global ISel] Add sext/zext improvements

[Dave Green via Phabricator via llvm-commits]

dmgreen added inline comments.


================
Comment at: llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp:4849
+  if (!mi_match(MI.getOperand(1).getReg(), MRI,
+                m_Copy(m_GExtractVectorElt(m_Reg(Src0), m_ICst(Lane)))))
+    return false;
----------------
aemerson wrote:
> Why are we trying to match a copy? These should have been combined away. If there are cases where they aren't, then we should probably manually match the pattern using a helper like `getOpcodeDef()` which can look through copies.
My understanding is that the COPY is a FPR -> GPR COPY, so is still needed. We can change it to getOpcodeDef, but I preferred the m_GExtractVectorElt version :)


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D108137/new/

https://reviews.llvm.org/D108137