[Bug tree-optimization/118727] [15 Regression] gcc.dg/pr108692.c fails on LoongArch

[xry111 at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118727

--- Comment #10 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
The difference from AArch64 and LoongArch64 is AArch64 has WIDEN_ABD, and (with
GCC 14.2):

t.c:10:17: note:   abd pattern recognized: patt_29 = (int) patt_30;
t.c:10:17: note:   extra pattern stmt: patt_30 = .VEC_WIDEN_ABD (a.0_4, b.1_6);
t.c:10:17: note:   vect_is_simple_use: operand ABS_EXPR <c_17>, type of def:
internal
t.c:10:17: note:   vect_is_simple_use: operand .VEC_WIDEN_ABD (a.0_4, b.1_6),
type of def: internal
t.c:10:17: note:   vect_is_simple_use: operand ABS_EXPR <c_17>, type of def:
internal
t.c:10:17: note:   vect_is_simple_use: operand .VEC_WIDEN_ABD (a.0_4, b.1_6),
type of def: internal
t.c:10:17: note:   vect_recog_sad_pattern: detected: r_18 = _8 + r_23;
t.c:10:17: note:   sad pattern recognized: patt_28 = SAD_EXPR <a.0_4, b.1_6,
r_23>;

So a different code path is used:

      if (gimple_call_internal_fn (abd_stmt) == IFN_ABD)
        {
==>       if (!vect_look_through_possible_promotion (vinfo, abd_oprnd0,  <==
LoongArch code path
                                                     &unprom[0])
              || !vect_look_through_possible_promotion (vinfo, abd_oprnd1,
                                                        &unprom[1]))
            return NULL;
        }
      else if (gimple_call_internal_fn (abd_stmt) == IFN_VEC_WIDEN_ABD)
        {
==>       unprom[0].op = abd_oprnd0;                         <== AArch64 code
path (already fixed in PR108692)
          unprom[0].type = TREE_TYPE (abd_oprnd0);
          unprom[1].op = abd_oprnd1;
          unprom[1].type = TREE_TYPE (abd_oprnd1);
        }
      else 
        return NULL;