nir: get rid of OOB dereferences in nir_lower_io_arrays_to_elements
This patch fixes mesa compiler crash in i965 on shaders like the following one: ``` in VS_OUTPUT { mat4 data; } vs_output; out vec4 fs_output; vec4 convert(in float val) { return vec4(val); } void main() { fs_output = vec4(0.0); for (int a = -1; a < 5; a++) { for (int b = -1; b < 5; b++) { fs_output += convert(vs_output.data[b][a]); } } } ``` Section 5.11 (Out-of-Bounds Accesses) of the GLSL 4.60 spec says: In the subsections described above for array, vector, matrix and structure accesses, any out-of-bounds access produced undefined behavior.... Out-of-bounds reads return undefined values, which include values from other variables of the active program or zero. Out-of-bounds writes may be discarded or overwrite other variables of the active program. GL_KHR_robustness and GL_ARB_robustness encourage us to return zero for reads. Reviewed-by: Rhys Perry <pendingchaos02@gmail.com> Signed-off-by: Andrii Simiklit <andrii.simiklit@globallogic.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6560>
This commit is contained in:
parent
33c9d4bf31
commit
d972a6ac4c
|
@ -115,6 +115,18 @@ lower_array(nir_builder *b, nir_intrinsic_instr *intr, nir_variable *var,
|
|||
{
|
||||
b->cursor = nir_before_instr(&intr->instr);
|
||||
|
||||
if (nir_deref_instr_is_known_out_of_bounds(nir_src_as_deref(intr->src[0]))) {
|
||||
/* See Section 5.11 (Out-of-Bounds Accesses) of the GLSL 4.60 */
|
||||
if (intr->intrinsic != nir_intrinsic_store_deref) {
|
||||
nir_ssa_def *zero = nir_imm_zero(b, intr->dest.ssa.num_components,
|
||||
intr->dest.ssa.bit_size);
|
||||
nir_ssa_def_rewrite_uses(&intr->dest.ssa,
|
||||
nir_src_for_ssa(zero));
|
||||
}
|
||||
nir_instr_remove(&intr->instr);
|
||||
return;
|
||||
}
|
||||
|
||||
nir_variable **elements =
|
||||
get_array_elements(varyings, var, b->shader->info.stage);
|
||||
|
||||
|
|
Loading…
Reference in New Issue