[Bug middle-end/90323] powerpc should convert equivalent sequences to vec_sel()

[luoxhu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90323

luoxhu at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |luoxhu at gcc dot gnu.org

--- Comment #8 from luoxhu at gcc dot gnu.org ---
Two minor updates for the case mentioned in #c2:

 for VEC_SEL (ARG1, ARG2, ARG3):

   Returns a vector containing the value of either ARG1 or ARG2 depending on
the 
   value of ARG3.


#include <stdio.h>
#include <altivec.h>
volatile vector unsigned orig = {0xebebebeb, 0x34343434, 0x76767676,
0x12121212};
volatile vector unsigned mask = {0xffffffff, 0, 0xffffffff, 0};
volatile vector unsigned fill = {0xfefefefe, 0xaaaaaaaa, 0xbbbbbbbb,
0xcccccccc};
volatile vector unsigned expected = {0xfefefefe, 0x34343434, 0xbbbbbbbb,
0x12121212};
__attribute__ ((noinline))
vector unsigned without_sel(vector unsigned l, vector unsigned r, vector
unsigned mask) {
-    l = l & ~r;
+    l = l & ~mask;
    l |= mask & r;
    return l;
}

__attribute__ ((noinline))
vector unsigned with_sel(vector unsigned l, vector unsigned r, vector unsigned
mask) {
-    return vec_sel(l, mask, r);
+    return vec_sel(l, r, mask);
}

int main() {
    vector unsigned res1 = without_sel(orig, fill, mask);
    vector unsigned res2 = with_sel(orig, fill, mask);
    if (!vec_all_eq(res1, expected)) printf ("error1\n");
    if (!vec_all_eq(res2, expected)) printf ("error2\n");
    return 0;
}


And the ASM would be:

without_sel:
        xxlxor 35,34,35
        xxland 35,35,36
        xxlxor 34,34,35
        blr
        .long 0
        .byte 0,0,0,0,0,0,0,0
with_sel:
        xxsel 34,34,35,36
        blr
        .long 0
        .byte 0,0,0,0,0,0,0,0