[Bug target/114184] [12/13 Regression] ICE: in extract_insn, at recog.cc:2812 (unrecognizable insn ) with _Complex long double and vector VCE

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114184

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:128860abd58605d616c184a9a68886a25862b2dd

commit r13-8446-g128860abd58605d616c184a9a68886a25862b2dd
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Mar 4 10:04:19 2024 +0100

    i386: Fix ICEs with SUBREGs from vector etc. constants to XFmode [PR114184]

    The Intel extended format has the various weird number categories,
    pseudo denormals, pseudo infinities, pseudo NaNs and unnormals.
    Those are not representable in the GCC real_value and so neither
    GIMPLE nor RTX VIEW_CONVERT_EXPR/SUBREG folding folds those into
    constants.

    As can be seen on the following testcase, because it isn't folded
    (since GCC 12, before that we were folding it) we can end up with
    a SUBREG of a CONST_VECTOR or similar constant, which isn't valid
    general_operand, so we ICE during vregs pass trying to recognize
    the move instruction.
    Initially I thought it is a middle-end bug, the movxf instruction
    has general_operand predicate, but the middle-end certainly never
    tests that predicate, seems moves are special optabs.
    And looking at other mov optabs, e.g. for vector modes the i386
    patterns use nonimmediate_operand predicate on the input, yet
    ix86_expand_vector_move deals with CONSTANT_P and SUBREG of CONSTANT_P
    arguments which if the predicate was checked couldn't ever make it through.

    The following patch handles this case similarly to the
    ix86_expand_vector_move's SUBREG of CONSTANT_P case, does it just for
XFmode
    because I believe that is the only mode that needs it from the scalar ones,
    others should just be folded.

    2024-03-04  Jakub Jelinek  <jakub@redhat.com>

            PR target/114184
            * config/i386/i386-expand.cc (ix86_expand_move): If XFmode op1
            is SUBREG of CONSTANT_P, force the SUBREG_REG into memory or
            register.

            * gcc.target/i386/pr114184.c: New test.

    (cherry picked from commit ea1c16f95b8fbaba4a7f3663ff9933ebedfb92a5)