[Bug c/100890] New: The "div" standard library functions could be optimised as builtins

[Bug c/100890] New: The "div" standard library functions could be optimised as builtins

[david at westcontrol dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100890

            Bug ID: 100890
           Summary: The "div" standard library functions could be
                    optimised as builtins
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: david at westcontrol dot com
  Target Milestone: ---

The C standard library has a family of functions for calculating the division
and remainder as a pair - "div", "ldiv", "lldiv", "imaxdiv".  These could be
optimised by the compiler using inline code, in the same manner as many other
library functions such as the "abs" family (listed under "Other builtins" in
the manual).

For example, "div" can be implemented as:

div_t div(int a, int b) {
    div_t d;
    d.quot = a / b;
    d.rem = a % b;
    return d;
}

Inlining this in place of a call to "div" results in code that is smaller and
faster on most targets, as well as providing far more optimisation
opportunities (constant propagation, re-arranging with other code, etc.).

[Bug c/100890] The "div" standard library functions could be optimised as builtins

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100890

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Dup of bug 70742.

*** This bug has been marked as a duplicate of bug 70742 ***