https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96681
Bug ID: 96681
Summary: Failure to optimize xor of comparisons with specific
constants to comparison of xor-ed of compared
variables
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 < 0) ^ (y < 0);
}
This can be optimized to `return (x ^ y) < 0;`. LLVM does this transformation,
but GCC does not. This transformation can also be done with `return (x > -1) ^
(y > -1);`. There is also a similar transformation with `return (x > -1) ^ (y <
0);`, which can be optimized to `return ~(x ^ y) < 0;`.
