https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105135
Bug ID: 105135
Summary: [11/12 Regression] Optimization regression for
handrolled branchless assignment
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: andre.schackier at gmail dot com
Target Milestone: ---
Given the following source code [godbolt](https://godbolt.org/z/rrP3bqGW7):
```cpp
char to_lower_1(const char c) { return c + ((c >= 'A' && c <= 'Z') * 32); }
char to_lower_2(const char c) { return c + (((c >= 'A') & (c <= 'Z')) * 32); }
char to_lower_3(const char c) {
if (c >= 'A' && c <= 'Z') {
return c + 32;
}
return c;
}
```
compiling with `-O3`
produces the following assembly
```asm
to_lower_1(char):
lea eax, [rdi-65]
cmp al, 25
setbe al
sal eax, 5
add eax, edi
ret
to_lower_2(char):
lea eax, [rdi-65]
cmp al, 25
setbe al
sal eax, 5
add eax, edi
ret
to_lower_3(char):
lea edx, [rdi-65]
lea eax, [rdi+32]
cmp dl, 26
cmovnb eax, edi
ret
```
Note that gcc-10.3 did produce the same assembly for all 3 functions while
gcc-11 and trunk do not.
