155bb74ea9
nir_opt_load_store_vectorize has an is_strided_vector() function that looks for types with weird explicit strides. It does so by comparing the explicit stride against the type-size-derived typical stride. This had a subtle bug. Simple vector types (vec2/3/4) have no explicit stride, so glsl_get_explicit_stride() returns 0. This never matches the typical stride for a vector, so is_strided_vector() would return true for basically any vector type, causing the vectorizer to bail. I found this by looking at a compute shader with scalar SSBO loads at offsets 0x220, 0x224, 0x228, 0x22c. nir_opt_load_store_vectorize would properly vectorize the first two into a vec2 load, but would refuse to extend it to a vec3 and ultimately vec4 load because is_strided_vector() saw a vec2 and freaked out. Neither ACO nor ANV do load/store vectorization before lowering derefs, so this shouldn't affect them. However, I'd like to fix this bug to avoid the trap for anyone who decides to in the future. In a branch where anv used this lowering, this cut an additional 38% of the send messages in the shader by properly vectorizing more things. Reviewed-by: Rhys Perry <pendingchaos02@gmail.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4255>
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