[Bug target/71921] [15/16 Regression] missed vectorization optimization

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71921

--- Comment #27 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by hongtao Liu <liuhongt@gcc.gnu.org>:

https://gcc.gnu.org/g:106e001b4bb5313a8d59b858e80d5633f90fcec0

commit r16-5846-g106e001b4bb5313a8d59b858e80d5633f90fcec0
Author: liuhongt <hongtao.liu@intel.com>
Date:   Mon Dec 1 00:51:26 2025 -0800

    Transform std::max(t, float(0)) into vmaxps w/o fast-math.

    The pattern is simplied to below since there's const0_operand

    (set (reg:V8SF 124)
        (and:V8SF (not:V8SF (lt:V8SF (reg:V8SF 123 [ MEM <const vector(8)
float> [(const float *)input_12(D) + ivtmp.30_4 * 1] ])
                    (const_vector:V8SF [
                            (const_double:SF 0.0 [0x0.0p+0]) repeated x8
                        ])))
            (reg:V8SF 123 [ MEM <const vector(8) float> [(const float
*)input_12(D) + ivtmp.30_4 * 1] ]))

    Add new combine pattern to match it.

    Also extend related avx512 pattern to accept immediate_operand, so
    that the optimization is also available under AVX512.

    The codegen is now better than before, however, vpxor is not hoisted
    outside of the loop after it's created in split1.

    gcc/ChangeLog:

            PR target/71921
            * config/i386/predicates.md (ieee_maxmin_comparison_operator):
            New predicator.
            * config/i386/sse.md (*minmax<mode>3_3): New define_insn_and_split.
            (*minmax<mode>3_4): Ditto.
            (*minmax<mode>3_1): Extend operands[2]/operands[4] to handle
            immediate_operand.

    gcc/testsuite/ChangeLog:

            * g++.target/i386/avx512-pr71921.C: New test.
            * g++.target/i386/pr71921.C: New test.