[Bug rtl-optimization/40667] [4.4/4.5 Regression] stack frames are generated even with -fomit-frame-pointer

["mikulas at artax dot karlin dot mff dot cuni dot cz" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #15 from mikulas at artax dot karlin dot mff dot cuni dot cz  2009-07-23 11:12 -------
The patch just walks around the problem and doesn't really fix it. It is simply
a hack that disables frame generation for long long, while for the other types
the same problem persists:

Example:
void g(double);
int f(double a)
{
        g(a);
        return 0;
}
(compile with -O2 -fomit-frame-pointer -mpreferred-stack-boundary=2)
--- here it still generates stack frame although it doesn't have to. Gcc 4.3 is
correct. Stack frame needs to be generated if
* the user requests it (no -fomit-frame-pointer)
* there is alloca
* there is stack realignment needed (either because of attribute that requests
it or SSE variables are on the stack)

--- in the above example, none of these three conditions are true, frame is not
realigned, yet the frame pointer is generated. The logic for deciding whether
to generate the frame pointer is flawed.

The current double regression is not as "critical" as the long long but it is
still incorrect.


-- 

mikulas at artax dot karlin dot mff dot cuni dot cz changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|FIXED                       |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40667