https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97641
Bug ID: 97641
Summary: Wrong codegen if optimizer is enabled
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dmitriy.ovdienko at gmail dot com
Target Milestone: ---
g++ optimizer produces wrong code in case if -O3 is used. In case if -O2 and
-O1 are used, app works as expected.
Expected output: matches
In fact output: does not match
```
//
// g++ -O3 test.cpp
//
#include <cstdio>
int Parse1(char const* ptr) noexcept
{
bool const negative = '-' == *ptr;
if (negative)
{
++ptr;
}
int result = 0;
while ('\x01' != *ptr)
{
result = result * 10 + *ptr++ - '0';
}
return negative ? -result : result;
}
int main()
{
if(-2147483648 != Parse1("-2147483648\x01"))
printf("does not match\n");
else
printf("matches\n");
}
```
