[Bug tree-optimization/103037] New: [11/12 Regression] Wrong code with -O2
vsevolod.livinskij at frtk dot ru
gcc-bugzilla@gcc.gnu.org
Tue Nov 2 07:17:23 GMT 2021
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103037
Bug ID: 103037
Summary: [11/12 Regression] Wrong code with -O2
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: ---
Link to the Compiler Explorer: https://godbolt.org/z/eaGzsPnax
Reproducer:
#include <stdio.h>
short var_3 = 2;
unsigned char var_9 = 23;
unsigned short var_11;
unsigned short arr_4 [23];
void test() __attribute__((noipa));
const unsigned short &min(unsigned short &d, const unsigned short &e) {
return e < d ? e : d;
}
void test() {
for (int a = 0; a < var_9; a += 3)
var_11 = min(arr_4[a], 1) / (arr_4[a] ? arr_4[a] : var_3);
}
int main() {
for (size_t i_0 = 0; i_0 < 23; ++i_0)
arr_4 [i_0] = 2;
test();
printf("%hu\n", var_11);
if (var_11 != 0)
__builtin_abort();
}
Error:
>$ g++ driver.cpp -O0 && ./a.out
0
>$ g++ driver.cpp -O2 && ./a.out
1
GCC version:
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/testing/gcc/bin_master/libexec/gcc/x86_64-pc-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /testing/gcc/gcc_src_master/configure --enable-multilib
--prefix=/testing/gcc/bin_master --disable-bootstrap
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20211101 (679652a77da60078392a834ed4b6b910127dbf24) (GCC)
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