Hi,
On Mon, 7 Sep 2015, Kugan wrote:
> For the following testcase (compiling with -O1; -O2 works fine), we have
> a stmt with stm_code SSA_NAME (_7 = _ 6) and for which _6 is defined by
> a GIMPLE_CALL. In this case, we are using wrong SUNREG promoted mode
> resulting in wrong code.
And why is that?
> Simple SSA_NAME copes are generally optimized
> but when they are not, we can end up using the wrong promoted mode.
> Attached patch fixes when we have one copy.
I think it's the wrong place to fixing up. Where does the wrong use come
from? At that place it should be fixed, not after the fact.
> _6 = bar5 (-10);
> ...
> _7 = _6;
> _3 = (long unsigned int) _6;
> ...
> if (_3 != l5.0_4)
There is no use of '_7' in this snippet so I don't see the relevance of
SUBREG_PROMOTED_MODE on it.
But whatever you do, please make sure you include the testcase for the
problem as a regression test:
> extern void abort (void);
>
> __attribute__ ((noinline))
> static unsigned short int foo5 (int x)
> {
> return x;
> }
>
> __attribute__ ((noinline))
> short int bar5 (int x)
> {
> return foo5 (x + 6);
> }
>
> unsigned long l5 = (short int) -4;
>
> int
> main (void)
> {
> if (bar5 (-10) != l5)
> abort ();
> return 0;
> }
Ciao,
Michael.
