https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69250
Bug ID: 69250
Summary: __attribute__ ((aligned(32))) not honored in classes
Product: gcc
Version: 5.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: tkoenig at gcc dot gnu.org
Target Milestone: ---
32-byte alignment (useful for avx) breaks when used in classes.
This is for 5.3 on x86_64-unknown-cygwin.
Test case:
#include <iostream>
#define ALIGN __attribute__ ((aligned(32)))
class Foo
{
public:
int a;
double x[24] ALIGN;
int b;
} ALIGN;
int main()
{
for (int i=0; i<5; i++)
{
Foo *p;
double *a;
p = new Foo;
a = new double;
unsigned long pv;
pv = (unsigned long) p->x;
if (pv % 32 != 0)
std::cout << "pv = " << pv << " is not divisble by 32" <<
" remainder is " << pv%32 << "\n";
else
std::cout << "pv = " << pv << " is divisble by 32\n";
}
}
Output:
pv = 25769945392 is not divisble by 32 remainder is 16
pv = 25770175232 is divisble by 32
pv = 25770175536 is not divisble by 32 remainder is 16
pv = 25770175840 is divisble by 32
pv = 25770176144 is not divisble by 32 remainder is 16
This is closely related to PR 65122, but IMHO not exactly a dup.
