[Bug tree-optimization/113119] ICE: verify_ssa failed: definition in block 18 does not dominate use in block 4 at -O1 with _BitInt

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113119

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:7590d975ecfdae4f112b5086c017101c08f07e3e

commit r14-7000-g7590d975ecfdae4f112b5086c017101c08f07e3e
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Jan 8 13:57:26 2024 +0100

    lower-bitint: Punt .*_OVERFLOW optimization if cast from IMAGPART_EXPR
appears before REALPART_EXPR [PR113119]

    _BitInt lowering for .{ADD,SUB,MUL}_OVERFLOW calls which have both
    REALPART_EXPR and IMAGPART_EXPR used and have a cast from the IMAGPART_EXPR
    to a boolean or normal integral type lowers them at the point of
    the REALPART_EXPR statement (which is especially needed if the lhs of
    the call is complex with large/huge _BitInt element type); we emit the
    stmt to set the lhs of the cast at the same spot as well.
    Normally, the lowering of __builtin_{add,sub,mul}_overflow arranges
    the REALPART_EXPR to come before IMAGPART_EXPR, followed by cast from that,
    but as the testcase shows, a redundant __builtin_*_overflow call and VN
    can reorder those and we then ICE because the def-stmt of the former cast
    from IMAGPART_EXPR may appear after its uses.
    We already check that all of REALPART_EXPR, IMAGPART_EXPR and the cast
    from the latter appear in the same bb as the .{ADD,SUB,MUL}_OVERFLOW call
    in the optimization, the following patch just extends it to make sure
    cast appears after REALPART_EXPR; if not, we punt on the optimization and
    expand it as a store of a complex _BitInt on the location of the ifn call.
    Only the testcase in the testsuite is changed by the patch, all other
    __builtin_*_overflow* calls in the bitint* tests (and there are quite a
few)
    have REALPART_EXPR first.

    2024-01-08  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/113119
            * gimple-lower-bitint.cc (optimizable_arith_overflow): Punt if
            both REALPART_EXPR and cast from IMAGPART_EXPR appear, but cast
            is before REALPART_EXPR.

            * gcc.dg/bitint-61.c: New test.