https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104120
Bug ID: 104120
Summary: slow compilation with only "-g3 -O1"; other opt levels
are fine
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: cnsun at uwaterloo dot ca
Target Milestone: ---
$ cat t.c
void acc_routine(void) {
int i, j, k, sum, diff;
for (i = 0; i < 10; i++)
for (j = 0; j < 10; j++)
for (k = 0; k < 10; k++)
sum = 1;
for (i = 0; i < 10; i++)
for (j = 0; j < 10; j++)
for (k = 0; k < 10; k++)
sum = 1;
for (i = 0; i < 10; i++)
for (j = 0; j < 10; j++)
for (k = 0; k < 10; k++)
sum = 1;
for (i = 0; i < 10; i++)
for (j = 0; j < 10; j++)
for (k = 0; k < 10; k++)
sum = 1;
for (i = 0; i < 10; i++)
for (j = 0; j < 10; j++)
for (k = 0; k < 10; k++)
sum = 1;
}
$
$ time gcc-trunk -c -g3 t.c -O1
real 0m43.205s
user 0m43.137s
sys 0m0.054s
$
$ time gcc-trunk -c -g3 t.c -O0
real 0m0.034s
user 0m0.022s
sys 0m0.012s
$ time gcc-trunk -c t.c -O1
real 0m0.043s
user 0m0.037s
sys 0m0.006s
$
$ time gcc-trunk -c t.c -O2
real 0m0.033s
user 0m0.027s
sys 0m0.007s
$ time gcc-trunk -c t.c -O3
real 0m0.032s
user 0m0.017s
sys 0m0.015s
$
$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/scratch/software/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/12.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /tmp/tmp.2nPqmFoxaU-gcc-builder/gcc/configure
--enable-languages=c,c++,lto --enable-checking-yes --enable-multiarch
--prefix=/scratch/software/gcc-trunk --disable-bootstrap
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.1 20220119 (experimental) [master -g1ead972ce] (GCC)
