[PATCH] D96119: [Codegenprepare][X86] Use usub with overflow opt for IV increment

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

This seems fine, but I was curious what kind of interaction we should expect between CGP and global-isel, so I tried to pushing the last test through llc:

  $ llc usub.ll -o - -global-isel 
  	.section	__TEXT,__text,regular,pure_instructions
  	.build_version macos, 10, 15
  LLVM ERROR: unable to legalize instruction: %4:_(s64), %5:_(s1) = G_USUBO %3:_, %6:_ (in function: test_02)

My understanding was that CGP is not needed with global-isel, but it's apparently running by default. Do we consider the current state of passes temporary and/or do we need to fix that crash before proceeding here?


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  https://reviews.llvm.org/D96119/new/

https://reviews.llvm.org/D96119