[Bug tree-optimization/80874] New: gcc does not emit cmov for minmax

[denis.campredon at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80874

            Bug ID: 80874
           Summary: gcc does not emit cmov for minmax
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: denis.campredon at gmail dot com
  Target Milestone: ---

Hello,
Considering the following code:
------------------
struct pair {
    int min, max;
};

pair minmax1(int x, int y) {
    if (x > y)
      return {y, x};
    else
      return {x, y};
}

#include <algorithm>

std::pair<int, int> minmax2(int x, int y) {
    return std::minmax(x, y);
}

auto minmax3(int x, int y) {
    return std::minmax(x, y);
}
-------------------
I've found that for minmax1 and minmax 2, gcc fails to emit cmov at -03.
Instead it produces the following:

minmax1(int, int):
        cmp     edi, esi
        jle     .L2
        mov     eax, edi
        mov     edi, esi
        mov     esi, eax
.L2:
        mov     eax, edi
        sal     rsi, 32
        or      rax, rsi
        ret
------------ 
For minmax3, the asm should be the same (I think), but it produces a more
complex code.