https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127538
--- Comment #7 from Drea Pinski <pinskia at gcc dot gnu.org> ---
That is :
```
Trying 33, 34 -> 35:
33: cc:CC=cmp(r102:DI,r103:DI)
34: r105:DI={(geu(cc:CC,0))?r103:DI:0}
REG_DEAD r103:DI
REG_DEAD cc:CC
35: r102:DI=r102:DI-r105:DI
REG_DEAD r105:DI
Failed to match this instruction:
(set (reg/v:DI 102 [ xD.4508 ])
(minus:DI (reg/v:DI 102 [ xD.4508 ])
(if_then_else:DI (geu (reg/v:DI 102 [ xD.4508 ])
(reg/v:DI 103 [ qD.4509 ]))
(reg/v:DI 103 [ qD.4509 ])
(const_int 0 [0]))))
```
Being matched.
What was happening in before was a few peepholes in aarch64.md even:
```
(define_peephole2
[(set (match_operand:GPI 0 "aarch64_general_reg")
(minus:GPI (match_operand:GPI 1 "aarch64_reg_or_zero")
(match_operand:GPI 2 "aarch64_reg_or_zero")))
(set (reg:CC CC_REGNUM)
(compare:CC
(match_dup 1)
(match_dup 2)))]
"!reg_overlap_mentioned_p (operands[0], operands[1])
&& !reg_overlap_mentioned_p (operands[0], operands[2])"
[(const_int 0)]
{
emit_insn (gen_sub<mode>3_compare1 (operands[0], operands[1],
operands[2]));
DONE;
}
)
...
```
