Bug with LTO optimizations in G++?
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
gcc-5 (Ubuntu) |
New
|
Undecided
|
Unassigned |
Bug Description
This code shows the bug:
---test.cc---
#include <stdio.h>
typedef __attribute__ ((__aligned__ (16))) struct _TEST_FLOAT128 {
__extension__ unsigned long long Part[2];
} TEST_FLOAT128;
int main( void )
{
TEST_FLOAT128 tf;
printf( "alignof(tf) = %d\n",(
printf( "alignof(struct _TEST_FLOAT128) = %d\n",(
printf( "alignof(
return 0;
}
---
$ g++-4.9 -O3 -flto -oalign test.cc -Wall -Wextra -g
# compiles without warnings.
$ g++-5 -O3 -flto -oalign test.cc -Wall -Wextra -g
test.cc:3:51: warning: type ‘struct _TEST_FLOAT128’ violates one definition rule [-Wodr]
typedef __attribute__ ((__aligned__ (16))) struct _TEST_FLOAT128 {
test.cc:5:3: note: a type with different alignment is defined in another translation unit
} TEST_FLOAT128;
^
# triggers a warning.
gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~ 16.04.4)