http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59660
--- Comment #8 from Jan Hubicka <hubicka at ucw dot cz> ---
Fe produces:
<cond_expr 0x7ffff7004840
type <integer_type 0x7ffff6ede690 int public SI
size <integer_cst 0x7ffff6ee03c0 constant 32>
unit size <integer_cst 0x7ffff6ee03e0 constant 4>
align 32 symtab 0 alias set -1 canonical type 0x7ffff6ede690 precision
32 min <integer_cst 0x7ffff6ee0360 -2147483648> max <integer_cst 0x7ffff6ee0380
2147483647>
pointer_to_this <pointer_type 0x7ffff6eea738>>
side-effects
arg 0 <truth_orif_expr 0x7ffff6fe5a78
type <boolean_type 0x7ffff6edebd0 _Bool public unsigned QI
size <integer_cst 0x7ffff6ee0200 constant 8>
unit size <integer_cst 0x7ffff6ee0220 constant 1>
align 8 symtab 0 alias set -1 canonical type 0x7ffff6edebd0
precision 1 min <integer_cst 0x7ffff6ee05c0 0> max <integer_cst 0x7ffff6ee0600
1>>
side-effects
arg 0 <eq_expr 0x7ffff6fe5a50 type <boolean_type 0x7ffff6edebd0 _Bool>
arg 0 <parm_decl 0x7ffff7006000 n> arg 1 <parm_decl 0x7ffff7006080
m>
/home/jh/t.c:5:13>
arg 1 <call_expr 0x7ffff7009000 type <boolean_type 0x7ffff6edebd0
_Bool>
side-effects
fn <addr_expr 0x7ffff6ff4740 type <pointer_type 0x7ffff7008000>
constant arg 0 <function_decl 0x7ffff6fea600 m_is_less_than_n>
/home/jh/t.c:5:37>
arg 0 <plus_expr 0x7ffff6fe5988 type <integer_type 0x7ffff6ede690
int>
arg 0 <parm_decl 0x7ffff7006000 n>
arg 1 <integer_cst 0x7ffff6ee0680 constant -1>
/home/jh/t.c:5:39> arg 1 <parm_decl 0x7ffff7006080 m>
/home/jh/t.c:5:37>
/home/jh/t.c:5:17>
arg 1 <integer_cst 0x7ffff6ee0640 type <integer_type 0x7ffff6ede690 int>
constant 1>
arg 2 <integer_cst 0x7ffff6ee0620 type <integer_type 0x7ffff6ede690 int>
constant 0>
/home/jh/t.c:5:17>
The sequence of jumps is produced in shortcut_cond_r an it seems we do this
silly thing for every conditional
where at least one of two has side effect.
The code produces basically
if (cond1)
goto true_label
if (cond2)
goto true_label
else
goto false_laebl
true_label:
tmp=1
goto jump_around
fasle_label;
tmp=2
jump_around:
It would make more sense to do
if (cond1)
goto true_label
tmp = cond2;
goto jump_around
true_label
tmp = true
jump_around:
It seems it would be always a win. I will see if my gimplifier-fu is on par to
hack this in.
