https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102622
Bug ID: 102622
Summary: Wrong code with -O3 for skylake-avx512 and
icelake-server
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: vsevolod.livinskij at frtk dot ru
Target Milestone: ---
Reproducer:
// func.cpp
#include <algorithm>
extern int var_20, var_22;
extern short arr_32[];
extern char arr_45[];
void test(int a, unsigned b, long long *c) {
for (short d = 0; d < 13; d++) {
for (int e = 0; e < a; e += 3)
var_20 = 0;
if (std::max(b, unsigned((short)b))) {
arr_32[d] = 0;
var_22 = *c;
}
for (unsigned f = 0; f < 69; f += 4)
arr_45[f] = 0;
}
}
driver.cpp
#include <stdio.h>
unsigned long long int a = 10693271954245845448ULL;
unsigned int b = 1144022456U;
long long int c = 42;
int var_20 = 0;
long long int var_22 = 0;
unsigned short arr_32 [13];
unsigned char arr_45 [69];
void test(int a, unsigned int b, long long int* c);
int main() {
test(a, b, &c);
printf("%llu\n", var_22);
}
Error:
>$ g++ -O3 -march=skylake-avx512 func.cpp driver.cpp && sde -skx -- ./a.out
0
>$ g++ -O2 -march=skylake-avx512 func.cpp driver.cpp && sde -skx -- ./a.out
42
GCC version:
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/testing/gcc/bin/libexec/gcc/x86_64-pc-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /testing/gcc/gcc_src/configure --enable-multilib
--prefix=/testing/gcc/bin --disable-bootstrap
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20211004 (154fd0896ef22fcf5235e35e2b795394dddd7a33) (GCC)
