[Bug middle-end/114669] New: use >= comparison when testing high bits

[goon.pri.low at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114669

            Bug ID: 114669
           Summary: use >= comparison when testing high bits
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: goon.pri.low at gmail dot com
  Target Milestone: ---

Example C functions

#include <stdint.h>
#include <stdbool.h>

bool unopt(uint32_t x) {
        return (x & 0xfff00000) == 0xfff00000;
}

bool opt(uint32_t x) {
        return x >= 0xfff00000;
}

Generated assembly

unopt:
        not     edi
        and     edi, -1048576
        sete    al
        ret
opt:
        cmp     edi, -1048577
        seta    al
        ret