https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100929
--- Comment #6 from Marc Glisse <glisse at gcc dot gnu.org> ---
(blend is now lowered in gimple)
For the integer case, the mix of vector(int) and vector(char) obfuscates things
a bit, we have
__m256i if_else_int (__m256i x, __m256i y)
{
vector(32) char _4;
vector(32) char _5;
vector(32) char _6;
vector(32) <signed-boolean:8> _7;
vector(32) char _8;
vector(4) long long int _9;
vector(8) int _10;
vector(8) int _11;
vector(8) <signed-boolean:32> _12;
vector(8) int _13;
<bb 2> [local count: 1073741824]:
_10 = VIEW_CONVERT_EXPR<vector(8) int>(x_2(D));
_11 = VIEW_CONVERT_EXPR<vector(8) int>(y_3(D));
_12 = _10 > _11;
_13 = VEC_COND_EXPR <_12, { -1, -1, -1, -1, -1, -1, -1, -1 }, { 0, 0, 0, 0,
0, 0, 0, 0 }>;
_5 = VIEW_CONVERT_EXPR<vector(32) char>(_13);
_4 = VIEW_CONVERT_EXPR<vector(32) char>(y_3(D));
_6 = VIEW_CONVERT_EXPR<vector(32) char>(x_2(D));
_7 = _5 < { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
_8 = VEC_COND_EXPR <_7, _4, _6>;
_9 = VIEW_CONVERT_EXPR<__m256i>(_8);
return _9;
}
A first step would be to teach gcc that it can do a VEC_COND_EXPR<_12, _11,
_10> with fewer VIEW_CONVERT_EXPR (maybe follow the definition chain of the
condition through trivial ops like <0, view_convert or ?-1:0 until we find a
real comparison _10 > _11, to determine the right size?).
Other steps:
* Move (or at least partially copy) fold_cond_expr_with_comparison to match.pd
so we can recognize min/max.
* Lower __builtin_ia32_cmpps256 (y_2(D), x_3(D), 17) to GIMPLE for the float
case, if that's a valid thing to do (NaN, etc).
