On 1/12/2026 2:58 PM, Andrew Pinski wrote:
I think this should be closer to what I did for VEC_SHL_INSERT in
r16-4742-gfcde4c81644aec (this was based on the review where I tried
to do a similar thing as you did:
https://gcc.gnu.org/pipermail/gcc-patches/2024-July/658275.html ).
That is, in fold_const_call (in fold-const.cc) add VEC_EXTRACT case
and do similar as fold_const_vec_shl_insert.
Something like:
```
static tree
fold_const_vec_extract (tree, tree arg0, tree arg1)
{
if (TREE_CODE (arg0) != VECTOR_CST)
return NULL_TREE;
/* vec_extract ( dup(CST), N) -> CST. */
if (tree elem = uniform_vector_p (arg0))
return elem;
return NULL_TREE;
}
```
And also in match.pd add:
```
(simplify
(IFN_VEC_EXTRACT (vec_duplicate @0) @1)
@0)
```
I don't think we need to care about the bounds check on @1 either
because then it would be undefined anyways.
Uniform vectors can come in different forms. They can be a
VEC_DUPLICATE, VECTOR_CST or even a CONSTRUCTOR node. uniform_vector_p
knows how to handle all three cases already. So while that solution is
simpler, I suspect it's leaving good opportunities on the floor and may
not even cover the regression in question (I haven't checked that).
Jeff
