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@SingleAccretion SingleAccretion commented Aug 24, 2022

The multi-reg restrictions do not apply to them.

Diffs - a few improvements as expected.

The multi-reg restrictions do not apply to them.
@ghost ghost added area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI community-contribution Indicates that the PR has been added by a community member labels Aug 24, 2022
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ghost commented Aug 24, 2022

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The multi-reg restrictions do not apply to them.

Author: SingleAccretion
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area-CodeGen-coreclr, community-contribution

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Comment on lines -694 to -701
#if defined(TARGET_X86) || defined(TARGET_ARM)
if (fwdSubNode->TypeGet() == TYP_LONG)
{
JITDUMP(" TYP_LONG fwd sub node, target is x86/arm\n");
return false;
}
#endif // defined(TARGET_X86) || defined(TARGET_ARM)

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Just a question. Why do we delete this code that skips TYP_LONG forward substitute node on x86 and arm target?

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It should not be necessary.

The restriction on substituting multi-reg nodes stems from the fact the backend (LSRA and codegen) can only handle a few select forms of uses for them:

  1. STORE_LCL_VAR(multi-reg node)
  2. RETURN(matching multi-reg call | LCL_VAR)

For structs, these restrictions are enforced by the frontend (mainly importer). For LONGs - by decomposition, which means we don't need to worry about them here.

@SingleAccretion SingleAccretion marked this pull request as ready for review August 25, 2022 09:58
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@dotnet/jit-contrib

@JulieLeeMSFT JulieLeeMSFT added this to the 8.0.0 milestone Aug 25, 2022
@AndyAyersMS AndyAyersMS merged commit 8c965ec into dotnet:main Aug 26, 2022
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Thanks again for all your hard work.

@SingleAccretion SingleAccretion deleted the FwdSub-Long-Calls branch August 26, 2022 19:18
@ghost ghost locked as resolved and limited conversation to collaborators Sep 26, 2022
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3 participants