Tested with gcc-4.2-20070131, with -O3 on i386. Gcc correctly writes the
constants directly into the variable called "out", but it still stores its
temporary result on the stack, from where it will never be read anymore.
gcc-4.1.1 DOES seem to eliminate these arrays, at least in the given example.
Don't know if that qualifies as regression though...
gcc-4.3-20070202 behaves the same as gcc-4.2-20070131.
void test(int * out) {
for (int j=0; j<4; ++j) {
int tmp[4];
for (int i=0; i<4; ++i) tmp[i] = i;
for (int i=0; i<4; ++i) out[i] = tmp[i];
}
}
--
Summary: Local arrays not eliminated by optimization
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: stefaan dot deroeck at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30697
