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.).
