https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111445
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
-Os -fallow-store-data-races -fdisable-tree-sccp -fno-tree-loop-im
makes the case simpler to look at, IVOPTs only mangles the last loop there:
Analyzing # of iterations of loop 2
exit condition [d_26 + 1, + , 1](no_overflow) <= 1
bounds on difference of bases: -255 ... 0
result:
zero if d_26 > 1
# of iterations 1 - (unsigned int) d_26, bounded by 1
number of iterations 1 - (unsigned int) d_26; zero if d_26 > 1
..
Selected IV set for loop 2 at t.c:22, 2 avg niters, 1 IVs:
Candidate 10:
Var befor: ivtmp.26_28
Var after: ivtmp.26_29
Incr POS: at end
IV struct:
Type: unsigned int
Base: (unsigned int) (d_26 + 1)
Step: 1
Biv: N
Overflowness wrto loop niter: No-overflow
changing
+ _31 = d_26 + 1;
+ ivtmp.26_30 = (unsigned int) _31;
goto <bb 6>; [100.00%]
<bb 5> [local count: 118111600]:
b.6_7 = b;
_8 = (int) b.6_7;
check (_8);
- e_21 = e_15 + 1;
+ ivtmp.26_29 = ivtmp.26_28 + 1;
<bb 6> [local count: 236223200]:
- # e_15 = PHI <0(10), e_21(5)>
+ # ivtmp.26_28 = PHI <ivtmp.26_30(10), ivtmp.26_29(5)>
_9 = (unsigned char) d_26;
_10 = _9 + 1;
_11 = (int) _10;
- _12 = (int) e_15;
- _13 = _11 + _12;
- if (_13 <= 1)
+ _32 = (int) ivtmp.26_28;
+ if (_32 <= 1)
goto <bb 5>; [50.00%]
else
goto <bb 7>; [50.00%]
