[Bug tree-optimization/106245] New: Failure to optimize (u8)(a << 7) >> 7 pattern to a & 1

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106245

            Bug ID: 106245
           Summary: Failure to optimize (u8)(a << 7) >> 7 pattern to a & 1
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gabravier at gmail dot com
  Target Milestone: ---

#include <stdint.h>

int8_t f(int8_t a)
{
    return (uint8_t)(a << 7) >> 7;
}

This can be optimized to `return a & 1;`. This transformation is done by LLVM,
but not by GCC.