microsoft / microsoft/DirectXShaderCompiler

Support IMul/UMul/UDiv with two outputs from HLSL

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enhancement high-impact
Dominant language
C++
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Forks
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Avg merge
2d 11h
Merged PRs (30d)
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Description

IMul/UMul/UDiv ops with two outputs have been part of the shader models since 4.0, but HLSL has never explicitly exposed these to HLSL so they could be fully used.

This is the suggestion that we should add new intrinsic functions to HLSL that map to these DXIL ops, which could open up scenarios without requiring the optional 64-bit support to be used.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading the HLSL intrinsic and DXIL operation context described in the issue, focusing on IMul, UMul, and UDiv with two outputs and their shader-model support. Define the required intrinsic shapes and verify that they map to the corresponding DXIL operations without requiring optional 64-bit support.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
compilers
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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