[PATCH] D148917: [AArch64][FastISel] Handle CRC32 intrinsics

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Okay.  I'm bringing it up because I'd like to make sure fastisel remains limited in scope; we don't have all the GlobalISel infrastructure, so reviewing any additions is significantly more work.  (For comparison, globalisel supports these intrinsics with zero globalisel-specific lines of code.)



================
Comment at: llvm/lib/Target/AArch64/AArch64FastISel.cpp:3802
+    MVT VT;
+    if (!isTypeLegal(II->getType(), VT))
+      return false;
----------------
You can assume intrinsics have the type declared in IntrinsicsAArch64.td; I don't think checking the type is legal does anything here.


================
Comment at: llvm/lib/Target/AArch64/AArch64FastISel.cpp:3841
+    Register ResultReg =
+        fastEmitInst_rr(Opc, &AArch64::GPR32RegClass, LHSReg, RHSReg);
+    if (!ResultReg)
----------------
I'm pretty sure fastEmitInst_rr can't fail, so there isn't any reason to null-check the return value.  Is this pattern copied from somewhere?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D148917/new/

https://reviews.llvm.org/D148917