https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115423
Bug ID: 115423
Summary: Inlined strcmp optimizes poorly
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
bool g(const char* c) {
return __builtin_strcmp(c, ".") == 0 ||
__builtin_strcmp(c, "..") == 0;
}
bool h(const char* c) {
return (c[0] == '.' && c[1] == '\0') ||
(c[0] == '.' && c[1] == '.' && c[2] == '\0');
}
Compile with -O2.
Expected result: Same output from both.
Actual: The former results in a mess that, among other inefficiencies, loads
c[0] twice.
Online reproducer: https://godbolt.org/z/E4vEshvcM
(I don't know if this is an RTL or tree optimizer issue, I just guessed. Feel
free to move it if it's wrong.)
