[CIR][CIRGen][Builtin][X86] Add support for tzcnt_u16, tzcnt_u32, and tzcnt_u64 #1691
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bcardosolopes
approved these changes
Jun 18, 2025
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Related: #1404
Implements codegen for the X86 builtins
tzcnt_u16,tzcnt_u32, andtzcnt_u64.While adding tests for both the Intel and AMD variants of BMI intrinsics, I ran into issues when placing them in the same file.
Both
_tzcnt_u16(Intel) and__tzcnt_u16(AMD) map to the same inline wrapper in <immintrin.h>. Whether they're isolated or both are present in a test file, Clang emits only one definition (__tzcnt_u16) which I think causes FileCheck mismatches i.e., the CHECK lines for the Intel version (test_tzcnt_u16) would fail when looking for_tzcnt_u16.I tried updating the CHECK lines for the Intel test to match the emitted symbol (
__tzcnt_u16), but it still failed unless the Intel test was run in isolation, and only when CHECK was updated to_tzcnt_u16even though__tzcnt_u16is what is emitted. I also experimented with split-file to isolate the tests, but that didn’t resolve the issue either.To keep the tests independent, I split the Intel and AMD tests into separate files. Was wondering if this was fine as in OG clang, both Intel and AMD variants are in the same file (https://github.com/llvm/clangir/blob/main/clang/test/CodeGen/X86/bmi-builtins.c)