https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107432
Bug ID: 107432
Summary: __builtin_convertvector generates inefficient code
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: g.peterh...@t-online.de
Target Milestone: ---
Example: conversion int64_t -> int32_t
avx512f + avx512vl
HW conversions are available.
avx2
There is a correctly working 32-bit-permutation
(_mm256_permutevar8x32_epi32/vpermd) that can be used.
I have not (yet) evaluated whether other conversions (larger int -> smaller
int) are also affected.
PS: On x86 it's already hell to optimize all cases depending on the instruction
set.
PPS: What about -march=znver4 ?
https://godbolt.org/z/3s79bnh7v
thx
Gero
