On Thu, Sep 24, 2026 at 11:11 PM Artemiy Volkov <[email protected]> wrote:
>
> In this simplification rule added in r17-4511-g885ad73e630ca2, we assume
> that C1 and C3 are of the same type and call wi::leu_p () with those
> constants converted to wide_int. This leads to a triggered assert on
> wide-int.h:1049 whenever C1 and C3 have different precision, which causes
> an ICE reported in PR127552. Fix this by converting to widest_int
> instead.
>
> To test the change, amend the original match-bit-extract-shift.c file to
> use constants of various types in the existing testcases.
>
> Bootstrapped and regtested on aarch64-linux-gnu and x86_64-linux-gnu.
>
> PR tree-optimization/127552
>
> gcc/ChangeLog:
>
> * match.pd: Fix constant comparison in ((X >> C1) & C2) << C3.
Ok.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/match-bit-extract-shift.c: Adjust testcases.
> ---
> gcc/match.pd | 2 +-
> .../gcc.dg/tree-ssa/match-bit-extract-shift.c | 14 +++++++-------
> 2 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index b6a9d4e79be..688357f0ecd 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -1545,7 +1545,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> tree mask_shifted = fold_build2 (LSHIFT_EXPR, TREE_TYPE (@0),
> mask, @3);
> }
> - (if (wi::leu_p (wi::to_wide (@1), wi::to_wide (@3)))
> + (if (wi::to_widest (@1) <= wi::to_widest (@3))
> (bit_and (lshift @0 (minus @3 @1)) { mask_shifted; })
> (bit_and (rshift @0 (minus @1 @3)) { mask_shifted; })))))))
>
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/match-bit-extract-shift.c
> b/gcc/testsuite/gcc.dg/tree-ssa/match-bit-extract-shift.c
> index 292ce5a41c9..56d386d4305 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/match-bit-extract-shift.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/match-bit-extract-shift.c
> @@ -6,33 +6,33 @@
>
> uint32_t f (uint64_t x)
> {
> - return (((x >> 32) & 0x1) << 16)
> - | (((x >> 24) & 0xff) << 8);
> + return (((x >> 32) & 0x1) << 16L)
> + | (((x >> 24UL) & 0xff) << 8);
> }
>
> uint32_t f2 (uint64_t x)
> {
> - return (((x >> 3) & 0x3) << 16);
> + return (((x >> 3) & 0x3) << 16LL);
> }
>
> uint32_t f3 (uint64_t x)
> {
> - return (((x >> 61) & 0xE) << 16);
> + return (((x >> 61ULL) & 0xE) << 16);
> }
>
> uint32_t f4 (uint64_t x)
> {
> - return (((x >> 62) & 0xE) << 16);
> + return (((x >> 62U) & 0xE) << 16UL);
> }
>
> uint32_t f5 (uint64_t x)
> {
> - return (((x >> 63) & 0xF) << 17);
> + return (((x >> 63L) & 0xF) << 17U);
> }
>
> uint64_t f6 (uint64_t x)
> {
> - return (((x >> 32) & 0xFFFFFF) << 47);
> + return (((x >> 32U) & 0xFFFFFF) << 47ULL);
> }
>
> /* { dg-final { scan-tree-dump-not "<< 16" forwprop1 } } */
> --
> 2.43.0
>
