https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110042
Bug ID: 110042
Summary: [14 Regression] missed cmov optimization after
r14-1014-gc5df248509b489364c573e8
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Target: aarch64-linux-gnu
Take:
```
unsigned
f1(int t, int t1)
{
int tt = 0;
if(t)
tt = (t1&0x8)!=0;
return tt;
}
```
On aarch64 we should produce:
```
cmp w0, 0
ubfx x0, x1, 3, 1
csel w0, w0, wzr, ne
ret
```
But on the trunk we get:
```
cbz w0, .L3
ubfx x0, x1, 3, 1
ret
.p2align 2,,3
.L3:
mov w0, 0
ret
```
The difference in the IR is:
old:
```
(insn 11 10 12 3 (set (reg:SI 97)
(lshiftrt:SI (reg/v:SI 96 [ t1 ])
(const_int 3 [0x3]))) "/app/example.cpp":7:18 782
{*aarch64_lshr_sisd_or_int_si3}
(expr_list:REG_DEAD (reg/v:SI 96 [ t1 ])
(nil)))
(insn 12 11 25 3 (set (reg:SI 94 [ <retval> ])
(and:SI (reg:SI 97)
(const_int 1 [0x1]))) "/app/example.cpp":7:18 533 {andsi3}
(expr_list:REG_DEAD (reg:SI 97)
(nil)))
```
new:
```
(insn 11 10 12 3 (set (subreg:DI (reg:SI 97) 0)
(zero_extract:DI (subreg:DI (reg/v:SI 96 [ t1 ]) 0)
(const_int 1 [0x1])
(const_int 3 [0x3]))) "/app/example.cpp":7:18 832 {*extzvdi}
(expr_list:REG_DEAD (reg/v:SI 96 [ t1 ])
(nil)))
(insn 12 11 24 3 (set (reg:SI 94 [ <retval> ])
(reg:SI 97)) "/app/example.cpp":8:10 64 {*movsi_aarch64}
(expr_list:REG_DEAD (reg:SI 97)
(nil)))
```
noce_try_cmove_arith handles the old one but not the new one for some reason:
```
if-conversion succeeded through noce_try_cmove_arith
``
