Re: [RFC] [v2] Extend fold_vec_perm to handle VLA vectors

[Richard Sandiford <richard.sandiford@arm.com>]

Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org> writes:
>> Unfortunately, the patch regressed following tests on ppc64le and
>> armhf respectively:
>> gcc.target/powerpc/vec-perm-ctor.c scan-tree-dump-not optimized
>> "VIEW_CONVERT_EXPR"
>> gcc.dg/tree-ssa/forwprop-20.c scan-tree-dump-not forwprop1 "VEC_PERM_EXPR"
>>
>> This happens because of the change to vect_cst_ctor_array which
>> removes handling of VECTOR_CST,
>> and thus we return NULL_TREE for cases where VEC_PERM_EXPR has
>> vector_cst, ctor input operands.
>>
>> For eg we fail to fold VEC_PERM_EXPR for the following test taken from
>> forwprop-20.c:
>> void f (double d, vecf* r)
>> {
>>   vecf x = { -d, 5 };
>>   vecf y = {  1, 4 };
>>   veci m = {  2, 0 };
>>   *r = __builtin_shuffle (x, y, m); // { 1, -d }
>> }
>> because vect_cst_ctor_to_array will now return NULL_TREE for vector_cst {1, 4}.
>>
>> The attached patch thus reverts the changes to vect_cst_ctor_to_array,
>> which makes the tests pass again.
>> I have put the patch for another round of bootstrap+test on the above
>> targets (aarch64, aarch64-sve, x86_64, armhf, ppc64le).
>> OK to commit if it passes ?
> The patch now passes bootstrap+test on all these targets.

OK, thanks.

Richard