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authorCaio Marcelo de Oliveira Filho <[email protected]>2019-03-27 15:07:20 -0700
committerCaio Marcelo de Oliveira Filho <[email protected]>2019-04-08 19:29:32 -0700
commitd08a74d2bf12721f450098cfac300b4f5bcc5dfc (patch)
tree9de234d328b46a90bdfdaa12bed8073f4fa82b75
parent3c5ddaeacd2c52bc11f9cda451fe640cff629bdd (diff)
nir/algebraic: Lower CS derivatives to zero when no group defined
In compute shaders if no derivative group is defined, the derivatives will always be zero. Specified in NV_compute_shader_derivatives. To make the check more convenient, add a "info" local variable to the generated code so we can refer to it in the Python rules. (Jason) Reviewed-by: Ian Romanick <[email protected]> Reviewed-by: Jason Ekstrand <[email protected]>
-rw-r--r--src/compiler/nir/nir_algebraic.py2
-rw-r--r--src/compiler/nir/nir_opt_algebraic.py12
2 files changed, 14 insertions, 0 deletions
diff --git a/src/compiler/nir/nir_algebraic.py b/src/compiler/nir/nir_algebraic.py
index d4b3bb5957f..4772d4d123d 100644
--- a/src/compiler/nir/nir_algebraic.py
+++ b/src/compiler/nir/nir_algebraic.py
@@ -770,7 +770,9 @@ ${pass_name}(nir_shader *shader)
bool progress = false;
bool condition_flags[${len(condition_list)}];
const nir_shader_compiler_options *options = shader->options;
+ const shader_info *info = &shader->info;
(void) options;
+ (void) info;
% for index, condition in enumerate(condition_list):
condition_flags[${index}] = ${condition};
diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index d6737995844..b8d418c2e49 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -972,6 +972,18 @@ for op in ['fadd', 'fmul', 'iadd', 'imul']:
((op, ('bcsel(is_used_once)', a, '#b', c), '#d'), ('bcsel', a, (op, b, d), (op, c, d)))
]
+# For derivatives in compute shaders, GLSL_NV_compute_shader_derivatives
+# states:
+#
+# If neither layout qualifier is specified, derivatives in compute shaders
+# return zero, which is consistent with the handling of built-in texture
+# functions like texture() in GLSL 4.50 compute shaders.
+for op in ['fddx', 'fddx_fine', 'fddx_coarse',
+ 'fddy', 'fddy_fine', 'fddy_coarse']:
+ optimizations += [
+ ((op, 'a'), 0.0, 'info->stage == MESA_SHADER_COMPUTE && info->cs.derivative_group == DERIVATIVE_GROUP_NONE')
+]
+
# This section contains "late" optimizations that should be run before
# creating ffmas and calling regular optimizations for the final time.
# Optimizations should go here if they help code generation and conflict