https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109009
--- Comment #2 from Surya Kumari Jangala <jskumari at gcc dot gnu.org> ---
For the working testcase:
long
foo (long i, long cond)
{
if (cond)
bar ();
return i;
}
The input RTL to the shrink wrap pass is:
BB2:
set r100, compare(r4, 0)
if r100 jump BB4 else jump BB3
BB3:
set mem(r1+32), r3
call bar()
set r3, mem(r1+32)
BB4:
return r3
The shrink wrap pass concludes that only BB3 requires a prolog and successfully
does shrink wrapping.
For the non-working case:
long
foo (long i, long cond)
{
if (cond)
bar ();
return i+1;
}
The input rtl to the shrink wrap pass is:
BB2:
set r100, compare(r4, 0)
set r31, r3
if r100 jump BB4 else jump BB3
BB3:
call bar()
BB4:
set r3, r31+1
return r3
The shrink wrap pass decides that both BB2 and BB3 require a prolog, and
finally the prolog is placed in BB2. Thus shrink wrapping fails for this test.
