On Fri, Sep 11, 2026 at 10:50 AM Hongyu Wang <[email protected]> wrote:
>
> Hi,
>
> The unordered compares (UNLT, UNLE, UNGT, UNGE and UNEQ) must not raise
> FE_INVALID on a quiet NaN. AVX and AVX512 have an imm8 encoding for the
> quiet _UQ predicate of each, so just select it.
>
> Legacy SSE2 has only 8 predicates and can express UNGE/UNGT/UNLT/UNLE
> only as the signaling NLT/NLE. So reject those four codes in the packed
> FP vec_cmp expanders under trapping math and NaNs are honored.
>
> Bootstrapped & regtested under x86_64-pc-linux-gnu. Ok for trunk?
>
> gcc/ChangeLog:
>
> PR target/127177
> * config/i386/i386-expand.cc (ix86_fp_cmp_code_to_pcmp_immediate):
> Return the _UQ predicate immediates for UNLE, UNLT, UNGE, UNGT and
> UNEQ.
> * config/i386/i386.cc (ix86_print_operand):Likewise to print the
> _uq suffixed AVX predicates for these codes.
> * config/i386/predicates.md (ix86_fp_vec_cmp_operator): New
> predicate.
> * config/i386/sse.md (vec_cmp<mode><sseintvecmodelower>): Use the
> new predicate for the VF_128 compare.
> * config/i386/mmx.md (vec_cmpv2sfv2si): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> PR target/127177
> * gcc.target/i386/pr127177-1.c: New test.
> * gcc.target/i386/pr127177-2.c: Likewise.
> * gcc.target/i386/pr127177-3.c: Likewise.
> * gcc.target/i386/pr127177-4.c: Likewise.
> * gcc.target/i386/pr127177-5.c: Likewise.
> +;; SSE2 doesn't have quiet vector compare for LT/LE/GT/GE, so
> +;; disable them under trapping-math or HONOR_NANS.
> +
> +(define_predicate "ix86_fp_vec_cmp_operator"
> + (and (match_operand 0 "comparison_operator")
> + (ior (not (match_code "unlt,unle,ungt,unge"))
> + (match_test "TARGET_AVX
> + || !flag_trapping_math
> + || !HONOR_NANS (GET_MODE (XEXP (op, 0)))"))))
FYI, binary operators (ior, and, ...) can have multiple inputs in
define_predicate, so:
(ior (not (match_code "..."))
(match_test "TARGET_AVX")
(not (match_test "flag_trapping_math"))
(not (match_test "HONOR_NANS (...)")))
Uros.
