[PATCH] D119013: [ArgPromotion][AMDGPU] New MSSA-based function argument promotion pass with input/output argument support

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


================
Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:711
+void ArgumentPromoter::promoteInOutArg(ArgPromotionInfo &ArgInfo,
+                                       RetValuesMap &RetValues) {
+  SmallDenseMap<BasicBlock *, SmallVector<Instruction *, 4>, 16> MemInsts;
----------------
For the actual promotion, have you considered making use of PromoteMemToReg? Basically, replace the old argument with an alloca that is stored on entry and read on exit, and then run mem2reg on that alloca?

```
define i32 @test(i32 %arg) {
  %old.arg = alloca i32
  store i32, i32* %old.arg
  // Code uses old.arg
  %ret = load i32, i32* %old.arg
  ret i32 %ret
}
```


================
Comment at: llvm/test/Transforms/ArgumentPromotion/inoutargs.ll:1
+; RUN: opt < %s -passes=mssaargpromotion -S | FileCheck %s
+
----------------
Please use update_test_checks.py.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119013/new/

https://reviews.llvm.org/D119013