[all-commits] [llvm/llvm-project] 00a831: [AArch64][SME] Extend Inliner cost-model with cust...

[Sander de Smalen via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 00a831421fdd94aec65221bdb37042c1aacfe8e0
      https://github.com/llvm/llvm-project/commit/00a831421fdd94aec65221bdb37042c1aacfe8e0
  Author: Sander de Smalen <sander.desmalen at arm.com>
  Date:   2023-10-31 (Tue, 31 Oct 2023)

  Changed paths:
    M llvm/include/llvm/Analysis/InlineCost.h
    M llvm/include/llvm/Analysis/TargetTransformInfo.h
    M llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
    M llvm/lib/Analysis/InlineCost.cpp
    M llvm/lib/Analysis/TargetTransformInfo.cpp
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
    M llvm/lib/Transforms/IPO/PartialInlining.cpp
    A llvm/test/Transforms/Inline/AArch64/sme-pstatesm-attrs-low-threshold.ll
    M llvm/test/Transforms/Inline/AArch64/sme-pstatesm-attrs.ll

  Log Message:
  -----------
  [AArch64][SME] Extend Inliner cost-model with custom penalty for calls. (#68416)

This is a stacked PR following on from #68415 

This patch has two purposes:
(1) It tries to make inlining more likely when it can avoid a
streaming-mode change.
(2) It avoids inlining when inlining causes more streaming-mode changes.

An example of (1) is:
```
  void streaming_compatible_bar(void);

  void foo(void) __arm_streaming {
    /* other code */
    streaming_compatible_bar();
    /* other code */
  }

  void f(void) {
    foo();            // expensive streaming mode change
  }

  ->

  void f(void) {
    /* other code */
    streaming_compatible_bar();
    /* other code */
  }
```
where it wouldn't have inlined the function when foo would be a
non-streaming function.

An example of (2) is:
```
  void streaming_bar(void) __arm_streaming;

  void foo(void) __arm_streaming {
    streaming_bar();
    streaming_bar();
  }

  void f(void) {
    foo();            // expensive streaming mode change
  }

  -> (do not inline into)

  void f(void) {
    streaming_bar();  // these are now two expensive streaming mode changes
    streaming_bar();
  }```