https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96685
Bug ID: 96685
Summary: Failure to optimize not+sub to add+not
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);
}
This can be optimized to `~x + y`. While this isn't necessarily faster on most
platforms, it is at least equivalent and on x86 the addition can be optimized
to `lea` whereas the subtraction can't. This transformation is done by LLVM,
but not by GCC.
