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authorKenneth Graunke <[email protected]>2015-11-29 23:23:44 -0800
committerKenneth Graunke <[email protected]>2015-12-22 15:57:59 -0800
commit0daf51e130f89d1e83fa897ef8df9229829f5b18 (patch)
tree62639d8529d9d83d6187871f6afb55f9a9d6c509 /src/glsl
parent7d539080c1a491aff9fb3e90c25df89884477aa8 (diff)
nir: Use writemasked store_vars in glsl_to_nir.
Instead of performing the read-modify-write cycle in glsl->nir, we can simply emit a partial writemask. For locals, nir_lower_vars_to_ssa will do the equivalent read-modify-write cycle for us, so we continue to get the same SSA values we had before. Because glsl_to_nir calls nir_lower_outputs_to_temporaries, all outputs are shadowed with temporary values, and written out as whole vectors at the end of the shader. So, most consumers will still not see partial writemasks. However, nir_lower_outputs_to_temporaries bails for tessellation control shader outputs. So those remain actual variables, and stores to those variables now get a writemask. nir_lower_io passes that through. This means that TCS outputs should actually work now. This is a functional change for tessellation control shaders. v2: Relax the nir_validate assert to allow partial writemasks. Signed-off-by: Kenneth Graunke <[email protected]> Reviewed-by: Jason Ekstrand <[email protected]>
Diffstat (limited to 'src/glsl')
-rw-r--r--src/glsl/nir/glsl_to_nir.cpp39
-rw-r--r--src/glsl/nir/nir_validate.c3
2 files changed, 10 insertions, 32 deletions
diff --git a/src/glsl/nir/glsl_to_nir.cpp b/src/glsl/nir/glsl_to_nir.cpp
index c0de7c4af98..0f0f4a133e0 100644
--- a/src/glsl/nir/glsl_to_nir.cpp
+++ b/src/glsl/nir/glsl_to_nir.cpp
@@ -1129,44 +1129,23 @@ nir_visitor::visit(ir_assignment *ir)
nir_ssa_def *src = evaluate_rvalue(ir->rhs);
if (ir->write_mask != (1 << num_components) - 1 && ir->write_mask != 0) {
- /*
- * We have no good way to update only part of a variable, so just load
- * the LHS and do a vec operation to combine the old with the new, and
- * then store it
- * back into the LHS. Copy propagation should get rid of the mess.
+ /* GLSL IR will give us the input to the write-masked assignment in a
+ * single packed vector. So, for example, if the writemask is xzw, then
+ * we have to swizzle x -> x, y -> z, and z -> w and get the y component
+ * from the load.
*/
-
- nir_intrinsic_instr *load =
- nir_intrinsic_instr_create(this->shader, nir_intrinsic_load_var);
- load->num_components = ir->lhs->type->vector_elements;
- nir_ssa_dest_init(&load->instr, &load->dest, num_components, NULL);
- load->variables[0] = lhs_deref;
- ralloc_steal(load, load->variables[0]);
- nir_builder_instr_insert(&b, &load->instr);
-
- nir_ssa_def *srcs[4];
-
+ unsigned swiz[4];
unsigned component = 0;
- for (unsigned i = 0; i < ir->lhs->type->vector_elements; i++) {
- if (ir->write_mask & (1 << i)) {
- /* GLSL IR will give us the input to the write-masked assignment
- * in a single packed vector. So, for example, if the
- * writemask is xzw, then we have to swizzle x -> x, y -> z,
- * and z -> w and get the y component from the load.
- */
- srcs[i] = nir_channel(&b, src, component++);
- } else {
- srcs[i] = nir_channel(&b, &load->dest.ssa, i);
- }
+ for (unsigned i = 0; i < 4; i++) {
+ swiz[i] = ir->write_mask & (1 << i) ? component++ : 0;
}
-
- src = nir_vec(&b, srcs, ir->lhs->type->vector_elements);
+ src = nir_swizzle(&b, src, swiz, num_components, !supports_ints);
}
nir_intrinsic_instr *store =
nir_intrinsic_instr_create(this->shader, nir_intrinsic_store_var);
store->num_components = ir->lhs->type->vector_elements;
- store->const_index[0] = (1 << store->num_components) - 1;
+ store->const_index[0] = ir->write_mask;
nir_deref *store_deref = nir_copy_deref(store, &lhs_deref->deref);
store->variables[0] = nir_deref_as_var(store_deref);
store->src[0] = nir_src_for_ssa(src);
diff --git a/src/glsl/nir/nir_validate.c b/src/glsl/nir/nir_validate.c
index 89cf0b89208..da920557d20 100644
--- a/src/glsl/nir/nir_validate.c
+++ b/src/glsl/nir/nir_validate.c
@@ -417,8 +417,7 @@ validate_intrinsic_instr(nir_intrinsic_instr *instr, validate_state *state)
assert(instr->variables[0]->var->data.mode != nir_var_shader_in &&
instr->variables[0]->var->data.mode != nir_var_uniform &&
instr->variables[0]->var->data.mode != nir_var_shader_storage);
- /* Currently, writemasks must cover the entire value */
- assert(instr->const_index[0] == (1 << instr->num_components) - 1);
+ assert((instr->const_index[0] & ~((1 << instr->num_components) - 1)) == 0);
break;
}
case nir_intrinsic_copy_var: