search for: sse41conversiontbl

Hi, I was going through the X86TTIImpl::getCastInstrCost, and got a doubt on cost calculation for TRUNCATE instruction in AVX mode. In AVX2ConversionTbl & AVXConversionTbl table there is no cost defined for TRUNCATE v16i32 to v16i8, as a fallback it goes to SSE41ConversionTbl table and there it finds cost as 30 for this operation. 30 cost for this operation looks very high. Wondering why such a high cost kept for this, any pointers to understand this will be helpful. In few cases this restricts better vectorization opportunities. Other observations: Cost for TRUNCATE...

...NCATE cost for AVX & AVX2 mode Hi, I was going through the X86TTIImpl::getCastInstrCost, and got a doubt on cost calculation for TRUNCATE instruction in AVX mode. In AVX2ConversionTbl & AVXConversionTbl table there is no cost defined for TRUNCATE v16i32 to v16i8, as a fallback it goes to SSE41ConversionTbl table and there it finds cost as 30 for this operation. 30 cost for this operation looks very high. Wondering why such a high cost kept for this, any pointers to understand this will be helpful. In few cases this restricts better vectorization opportunities. Other observations: Cost for TRUNCATE...