radeonsi/nir: don't run si_nir_opts again if there is no change

0.3% less overhead

Reviewed-by: Pierre-Eric Pelloux-Prayer <[email protected]>
Reviewed-by: Connor Abbott <[email protected]>

3 files changed, 16 insertions, 12 deletions

diff --git a/src/amd/llvm/ac_nir_to_llvm.c b/src/amd/llvm/ac_nir_to_llvm.c
index 2eba80a9c38..210a37a3906 100644
--- a/src/amd/llvm/ac_nir_to_llvm.c
+++ b/src/amd/llvm/ac_nir_to_llvm.c
@@ -4783,17 +4783,19 @@ void ac_nir_translate(struct ac_llvm_context *ac, struct ac_shader_abi *abi,
 	ralloc_free(ctx.vars);
 }
 
-void
+bool
 ac_lower_indirect_derefs(struct nir_shader *nir, enum chip_class chip_class)
 {
+	bool progress = false;
+
 	/* Lower large variables to scratch first so that we won't bloat the
 	 * shader by generating large if ladders for them. We later lower
 	 * scratch to alloca's, assuming LLVM won't generate VGPR indexing.
 	 */
-	NIR_PASS_V(nir, nir_lower_vars_to_scratch,
-		   nir_var_function_temp,
-		   256,
-		   glsl_get_natural_size_align_bytes);
+	NIR_PASS(progress, nir, nir_lower_vars_to_scratch,
+		 nir_var_function_temp,
+		 256,
+		 glsl_get_natural_size_align_bytes);
 
 	/* While it would be nice not to have this flag, we are constrained
 	 * by the reality that LLVM 9.0 has buggy VGPR indexing on GFX9.
@@ -4825,7 +4827,8 @@ ac_lower_indirect_derefs(struct nir_shader *nir, enum chip_class chip_class)
 	 */
 	indirect_mask |= nir_var_function_temp;
 
-	nir_lower_indirect_derefs(nir, indirect_mask);
+	progress |= nir_lower_indirect_derefs(nir, indirect_mask);
+	return progress;
 }
 
 static unsigned
diff --git a/src/amd/llvm/ac_nir_to_llvm.h b/src/amd/llvm/ac_nir_to_llvm.h
index 7c2d6b31955..b4ad68abb9e 100644
--- a/src/amd/llvm/ac_nir_to_llvm.h
+++ b/src/amd/llvm/ac_nir_to_llvm.h
@@ -46,7 +46,7 @@ static inline unsigned ac_llvm_reg_index_soa(unsigned index, unsigned chan)
 	return (index * 4) + chan;
 }
 
-void ac_lower_indirect_derefs(struct nir_shader *nir, enum chip_class);
+bool ac_lower_indirect_derefs(struct nir_shader *nir, enum chip_class);
 
 bool ac_are_tessfactors_def_in_all_invocs(const struct nir_shader *nir);
 
diff --git a/src/gallium/drivers/radeonsi/si_shader_nir.c b/src/gallium/drivers/radeonsi/si_shader_nir.c
index ccb80f30f4a..850be07ac40 100644
--- a/src/gallium/drivers/radeonsi/si_shader_nir.c
+++ b/src/gallium/drivers/radeonsi/si_shader_nir.c
@@ -1004,14 +1004,15 @@ static void si_lower_nir(struct si_screen *sscreen, struct nir_shader *nir)
 	 *
 	 * st/mesa calls finalize_nir twice, but we can't call this pass twice.
 	 */
+	bool changed = false;
 	if (!nir->constant_data) {
-		NIR_PASS_V(nir, nir_opt_large_constants,
-			   glsl_get_natural_size_align_bytes, 16);
+		NIR_PASS(changed, nir, nir_opt_large_constants,
+			 glsl_get_natural_size_align_bytes, 16);
 	}
 
-	ac_lower_indirect_derefs(nir, sscreen->info.chip_class);
-
-	si_nir_opts(nir);
+	changed |= ac_lower_indirect_derefs(nir, sscreen->info.chip_class);
+	if (changed)
+		si_nir_opts(nir);
 
 	NIR_PASS_V(nir, nir_lower_bool_to_int32);
 	NIR_PASS_V(nir, nir_remove_dead_variables, nir_var_function_temp);