[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - add MMX/SSE/AVX/AVX512 VPSADBW intrinsics to be used in constexpr · llvm/llvm-project#188062

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backend:X86clang:bytecodeclang:frontendconstexprgood first issue

描述

The horizontal sum of difference intrinsics can all be used in constexpr with suitable handling of the builtins inside VectorExprEvaluator::VisitCallExpr and InterBuiltin.cpp, and testing in the relevent *-builtins.c files.

_mm_sad_epu8 _mm256_sad_epu8 _mm512_sad_epu8 _mm_sad_pu8

Care needs to be taken with the signed/unsigned extension of the arguments - we might need to adjust the builtin signatures.

Review other sub-issues from #30794 on implementation

Split off from #157522

貢獻者指南

技術棧: cpp
領域: backend
議題類型: feature
難度: 4
預計時間: over 1 week
活動狀態: active
清晰度: mostly clear
前置要求: LLVM VectorExprEvaluatorSSE/AVX intrinsicsC++ constexprLLVM testing
新手友善度: 15
研究方向: Study the existing handling of similar intrinsics in VectorExprEvaluator::VisitCallExpr and InterpretBuiltin.cpp. Review the patterns used in sub issues from #30794 for implementing constexpr intrinsics. Pay attention to sign/zero extension handling in builtin signatures. Implement mm sad epu8, mm256 sad epu8, mm512 sad epu8, and mm sad pu8 with corresponding tests in * builtins.c files.