[Bug tree-optimization/96696] New: Failure to optimize div+mul to mod+sub

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96696

            Bug ID: 96696
           Summary: Failure to optimize div+mul to mod+sub
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gabravier at gmail dot com
  Target Milestone: ---

int f(int x, int y)
{
    return (x / y) * y;
}

This can be optimized to `return x - (x % y);`. This transformation is done by
LLVM, but not by GCC.