[Bug middle-end/38126] suboptimal code for (a && b || !a && !b)

[msebor at gmail dot com]

------- Comment #1 from msebor at gmail dot com  2009-09-12 23:33 -------
Code involving bool variables is similarly suboptimal:

$ cat t.cpp && gcc -O2 -S t.cpp && cat t.s
bool foo (bool a, bool b) {
    return a && b || !a && !b;
}

bool bar (bool a, bool b) {
    return a == b;
}
        .file   "t.cpp"
        .text
        .p2align 4,,15
.globl _Z3foobb
        .type   _Z3foobb, @function
_Z3foobb:
.LFB0:
        .cfi_startproc
        .cfi_personality 0x3,__gxx_personality_v0
        movl    %esi, %edx
        movl    %esi, %eax
        xorl    $1, %edx
        testb   %dil, %dil
        cmove   %edx, %eax
        ret
        .cfi_endproc
.LFE0:
        .size   _Z3foobb, .-_Z3foobb
        .p2align 4,,15
.globl _Z3barbb
        .type   _Z3barbb, @function
_Z3barbb:
.LFB1:
        .cfi_startproc
        .cfi_personality 0x3,__gxx_personality_v0
        cmpb    %dil, %sil
        sete    %al
        ret
        .cfi_endproc
.LFE1:
        .size   _Z3barbb, .-_Z3barbb
        .ident  "GCC: (GNU) 4.4.1 20090725 (Red Hat 4.4.1-2)"
        .section        .note.GNU-stack,"",@progbits


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38126