[PATCH] D130076: [llvm/CodeGen] Enable the ExpandLargeDivRem pass for X86, Arm and AArch64

Mon Sep 12 05:51:50 PDT 2022

arsenm added inline comments.

================
Comment at: llvm/include/llvm/Analysis/TargetTransformInfo.h:690-691

+  /// Returns the maximum bitwidth of legal div and rem instructions.
+  unsigned maxLegalDivRemBitWidth() const;
+
----------------
mgehre-amd wrote:
> arsenm wrote:
> > arsenm wrote:
> > > TargetTransformInfo isn't really the appropriate place to put something for a lowering decision. TargetLowering would make more sense
> > The name here is also misleading. It's not the max legal width, just the maximum codegen supports. 128 is still not really legal in the normal use of the term
> Hi @arsenm, thanks for pointing this out!
> 
> I prepared a PR to move this over to TargetLowering under the name `maxSupportedDivRemBitWidth`.
> This works with the old pass manager, but I cannot figure out to get a `TargetLowering`/`TargetPassConfig` with the new pass manager.
> Do you have an idea?
CodeGen is only using the old pass manager so it's a bit of moot point right now

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D130076/new/

https://reviews.llvm.org/D130076