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[X86] X86LegalizerInfo - use LegalFor instead if LegalIf for simple ISA/test pairs #138259

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RKSimon opened this issue May 2, 2025 · 5 comments
Open

[X86] X86LegalizerInfo - use LegalFor instead if LegalIf for simple ISA/test pairs #138259

RKSimon opened this issue May 2, 2025 · 5 comments
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@YLChenZ
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backend:X86 good first issue https://github.com/llvm/llvm-project/contribute llvm:globalisel

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@RKSimon
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RKSimon commented May 2, 2025

We have lots of arg/result common type cases like:

  getActionDefinitionsBuilder({G_ADD, G_SUB})
      .legalIf([=](const LegalityQuery &Query) -> bool {
        if (typeInSet(0, {s8, s16, s32})(Query))
          return true;
        if (Is64Bit && typeInSet(0, {s64})(Query))
          return true;
        if (HasSSE2 && typeInSet(0, {v16s8, v8s16, v4s32, v2s64})(Query))
          return true;
        if (HasAVX2 && typeInSet(0, {v32s8, v16s16, v8s32, v4s64})(Query))
          return true;
        if (HasAVX512 && typeInSet(0, {v16s32, v8s64})(Query))
          return true;
        if (HasBWI && typeInSet(0, {v64s8, v32s16})(Query))
          return true;
        return false;
      })

which should be simplified to use the legalFor({Types}) or legalFor(Pred, {Types}) helpers:

  getActionDefinitionsBuilder({G_ADD, G_SUB})
      .legalFor({s8, s16, s32})
      .legalFor(Is64Bit, {s64})
      .legalFor(HasSSE2, {v16s8, v8s16, v4s32, v2s64})
 --- etc ---
@RKSimon RKSimon added backend:X86 good first issue https://github.com/llvm/llvm-project/contribute llvm:globalisel labels May 2, 2025
@llvmbot
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llvmbot commented May 2, 2025

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

  1. Check that no other contributor has already been assigned to this issue. If you believe that no one is actually working on it despite an assignment, ping the person. After one week without a response, the assignee may be changed.
  2. In the comments of this issue, request for it to be assigned to you, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
  3. Fix the issue locally.
  4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
  5. Create a Git commit.
  6. Run git clang-format HEAD~1 to format your changes.
  7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

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llvmbot commented May 2, 2025

@llvm/issue-subscribers-backend-x86

Author: Simon Pilgrim (RKSimon)

We have lots of arg/result common type cases like: ```cpp getActionDefinitionsBuilder({G_ADD, G_SUB}) .legalIf([=](const LegalityQuery &Query) -> bool { if (typeInSet(0, {s8, s16, s32})(Query)) return true; if (Is64Bit && typeInSet(0, {s64})(Query)) return true; if (HasSSE2 && typeInSet(0, {v16s8, v8s16, v4s32, v2s64})(Query)) return true; if (HasAVX2 && typeInSet(0, {v32s8, v16s16, v8s32, v4s64})(Query)) return true; if (HasAVX512 && typeInSet(0, {v16s32, v8s64})(Query)) return true; if (HasBWI && typeInSet(0, {v64s8, v32s16})(Query)) return true; return false; }) ``` which should be simplified to use the legalFor({Types}) or legalFor(Pred, {Types}) helpers: ```cpp getActionDefinitionsBuilder({G_ADD, G_SUB}) .legalFor({s8, s16, s32}) .legalFor(Is64Bit, {s64}) .legalFor(HasSSE2, {v16s8, v8s16, v4s32, v2s64}) --- etc --- ```

@llvmbot
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llvmbot commented May 2, 2025

@llvm/issue-subscribers-good-first-issue

Author: Simon Pilgrim (RKSimon)

We have lots of arg/result common type cases like: ```cpp getActionDefinitionsBuilder({G_ADD, G_SUB}) .legalIf([=](const LegalityQuery &Query) -> bool { if (typeInSet(0, {s8, s16, s32})(Query)) return true; if (Is64Bit && typeInSet(0, {s64})(Query)) return true; if (HasSSE2 && typeInSet(0, {v16s8, v8s16, v4s32, v2s64})(Query)) return true; if (HasAVX2 && typeInSet(0, {v32s8, v16s16, v8s32, v4s64})(Query)) return true; if (HasAVX512 && typeInSet(0, {v16s32, v8s64})(Query)) return true; if (HasBWI && typeInSet(0, {v64s8, v32s16})(Query)) return true; return false; }) ``` which should be simplified to use the legalFor({Types}) or legalFor(Pred, {Types}) helpers: ```cpp getActionDefinitionsBuilder({G_ADD, G_SUB}) .legalFor({s8, s16, s32}) .legalFor(Is64Bit, {s64}) .legalFor(HasSSE2, {v16s8, v8s16, v4s32, v2s64}) --- etc --- ```

@YLChenZ
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YLChenZ commented May 2, 2025

@RKSimon Hi, I think I have found the location that needs to be modified:

llvm-project/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp

Line 150 in 52d2b58

.legalIf([=](const LegalityQuery &Query) -> bool {

llvm-project/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp

Line 189 in 52d2b58

.legalIf([=](const LegalityQuery &Query) -> bool {

llvm-project/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp

Line 249 in 52d2b58

.legalIf([=](const LegalityQuery &Query) -> bool {

etc.
It should be modified like this:

getActionDefinitionsBuilder({G_ADD, G_SUB})
  .legalFor({s8,  s16, s32})           
  .legalFor(Is64Bit, {s64})            
  .legalFor(HasSSE2, {v16s8, v8s16, v4s32, v2s64})  
  .legalFor(HasAVX2, {v32s8, v16s16, v8s32, v4s64})   
  .legalFor(HasAVX512, {v16s32, v8s64})             
  .legalFor(HasBWI, {v64s8, v32s16});

Could I get assigned?

@RKSimon
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RKSimon commented May 2, 2025

CC @e-kud

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