From 4b69ae8e1eaaf6591f8e76ec64bf0bc2dcfeb019 Mon Sep 17 00:00:00 2001 From: Jesse Natalie Date: Sun, 11 Apr 2021 19:15:35 -0700 Subject: [PATCH] nir_opt_deref: ptr_as_array(deref_cast(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 Part-of: --- src/compiler/nir/nir_deref.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/compiler/nir/nir_deref.c b/src/compiler/nir/nir_deref.c index 73a6d39..bc8c4e8 100644 --- a/src/compiler/nir/nir_deref.c +++ b/src/compiler/nir/nir_deref.c @@ -1123,7 +1123,8 @@ opt_deref_ptr_as_array(nir_builder *b, nir_deref_instr *deref) if (nir_src_is_const(deref->arr.index) && nir_src_as_int(deref->arr.index) == 0) { /* 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 * 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. */ if (parent->deref_type == nir_deref_type_cast && + parent->cast.align_mul == 0 && is_trivial_deref_cast(parent)) parent = nir_deref_instr_parent(parent); nir_ssa_def_rewrite_uses(&deref->dest.ssa, -- 2.7.4