[Bug rtl-optimization/105338] New: Regression: jump or cmove generated for pattern (x ? CST : 0)

["denis.campredon at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105338

            Bug ID: 105338
           Summary: Regression: jump or cmove generated for pattern (x ?
                    CST : 0)
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: denis.campredon at gmail dot com
  Target Milestone: ---

int f(int i) {
    return i ? 5 : 0;
}

int g(int i) {
    return i ? -2 : 0;
}

int h(int b) {
    return !!b * -2;
}

int i(int b) {
    return !!b * 5;
}

int j(int b) {
    if (!b) return 0;
    return -2;
}
-------------
With -02 gcc 11.2 the five functions above output branchless code like:

f(int):
        neg     edi
        sbb     eax, eax
        and     eax, 5
        ret
g(int):
        neg     edi
        sbb     eax, eax
        and     eax, -2
        ret
...
--------------

Whereas -02 gcc 12 now outputs a cmov or jump depending of sign of the
constant:
f(int):
        mov     eax, edi
        test    edi, edi
        mov     edx, 5
        cmovne  eax, edx
        ret

g(int):
        mov     eax, edi
        test    edi, edi
        jne     .L11
        ret
.L11:
        mov     eax, -2
        ret

h(int):
        mov     eax, edi
        test    edi, edi
        jne     .L17
        ret
.L17:
        mov     eax, -2
        ret

i(int):
        mov     eax, edi
        test    edi, edi
        mov     edx, 5
        cmovne  eax, edx
        ret

j(int):
        mov     eax, edi
        test    edi, edi
        mov     edx, -2
        cmovne  eax, edx
        ret
---------------------------

Alternatively, with the following code

int k(int b) {
    bool b2 = b;
    return b2 * 5;
}
----------------

Both gcc 12 and 11.2 are outputing
k(int):
        xor     eax, eax
        test    edi, edi
        setne   al
        lea     eax, [rax+rax*4]
        ret