nir_opt_deref: ptr_as_array(deref_cast<T*>(x))[0] isn't the same as x[0] if the cast has alignment

This breaks CLOn12's handling of CL CTS test_basic vector_creation for char3 (at least).
Removing this cast causes us to try to load from a deref with no alignment info.

Fixes: 99bb2a4d ("nir/opt_deref: Don't remove casts with alignment information")
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10165>
This commit is contained in:
Jesse Natalie
2021-04-11 19:15:35 -07:00
committed by Marge Bot
parent 70aefe3449
commit 4b69ae8e1e

View File

@@ -1123,7 +1123,8 @@ opt_deref_ptr_as_array(nir_builder *b, nir_deref_instr *deref)
if (nir_src_is_const(deref->arr.index) && if (nir_src_is_const(deref->arr.index) &&
nir_src_as_int(deref->arr.index) == 0) { nir_src_as_int(deref->arr.index) == 0) {
/* If it's a ptr_as_array deref with an index of 0, it does nothing /* If it's a ptr_as_array deref with an index of 0, it does nothing
* and we can just replace its uses with its parent. * and we can just replace its uses with its parent, unless it has
* alignment information.
* *
* The source of a ptr_as_array deref always has a deref_type of * The source of a ptr_as_array deref always has a deref_type of
* nir_deref_type_array or nir_deref_type_cast. If it's a cast, it * nir_deref_type_array or nir_deref_type_cast. If it's a cast, it
@@ -1132,6 +1133,7 @@ opt_deref_ptr_as_array(nir_builder *b, nir_deref_instr *deref)
* opt_deref_cast() above. * opt_deref_cast() above.
*/ */
if (parent->deref_type == nir_deref_type_cast && if (parent->deref_type == nir_deref_type_cast &&
parent->cast.align_mul == 0 &&
is_trivial_deref_cast(parent)) is_trivial_deref_cast(parent))
parent = nir_deref_instr_parent(parent); parent = nir_deref_instr_parent(parent);
nir_ssa_def_rewrite_uses(&deref->dest.ssa, nir_ssa_def_rewrite_uses(&deref->dest.ssa,