[Mesa-dev] [PATCH v3 1/4] radv: gather more info about push constants

[Samuel Pitoiset]

This is needed in order to inline some push constants when possible.
This also adds a new helper for initializing the pass.

v3: - track if shaders only use 32-bit push constants
    - compute min/max based on offset and number of components
v2: - use MIN2/MAX2
    - use UINT8_MAX

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>

fix gather
---
 src/amd/vulkan/radv_nir_to_llvm.c |  2 ++
 src/amd/vulkan/radv_private.h     |  2 ++
 src/amd/vulkan/radv_shader.h      |  4 ++++
 src/amd/vulkan/radv_shader_info.c | 37 ++++++++++++++++++++++++++++++-
 4 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/src/amd/vulkan/radv_nir_to_llvm.c b/src/amd/vulkan/radv_nir_to_llvm.c
index 7f74678d5f1..dbeae2aafde 100644
--- a/src/amd/vulkan/radv_nir_to_llvm.c
+++ b/src/amd/vulkan/radv_nir_to_llvm.c
@@ -3439,6 +3439,8 @@ LLVMModuleRef ac_translate_nir_to_llvm(struct ac_llvm_compiler *ac_llvm,
 
 	memset(shader_info, 0, sizeof(*shader_info));
 
+	radv_nir_shader_info_init(&shader_info->info);
+
 	for(int i = 0; i < shader_count; ++i)
 		radv_nir_shader_info_pass(shaders[i], options, &shader_info->info);
 
diff --git a/src/amd/vulkan/radv_private.h b/src/amd/vulkan/radv_private.h
index d4a9e9f0e95..1e38a12a2a7 100644
--- a/src/amd/vulkan/radv_private.h
+++ b/src/amd/vulkan/radv_private.h
@@ -1951,6 +1951,8 @@ void radv_nir_shader_info_pass(const struct nir_shader *nir,
 			       const struct radv_nir_compiler_options *options,
 			       struct radv_shader_info *info);
 
+void radv_nir_shader_info_init(struct radv_shader_info *info);
+
 struct radeon_winsys_sem;
 
 #define RADV_DEFINE_HANDLE_CASTS(__radv_type, __VkType)		\
diff --git a/src/amd/vulkan/radv_shader.h b/src/amd/vulkan/radv_shader.h
index b67cd2b4f15..92886188459 100644
--- a/src/amd/vulkan/radv_shader.h
+++ b/src/amd/vulkan/radv_shader.h
@@ -162,6 +162,10 @@ struct radv_streamout_info {
 
 struct radv_shader_info {
 	bool loads_push_constants;
+	uint8_t min_push_constant_used;
+	uint8_t max_push_constant_used;
+	bool has_only_32bit_push_constants;
+	bool has_indirect_push_constants;
 	uint32_t desc_set_used_mask;
 	bool needs_multiview_view_index;
 	bool uses_invocation_id;
diff --git a/src/amd/vulkan/radv_shader_info.c b/src/amd/vulkan/radv_shader_info.c
index 7e5a3789af2..00c11eb447a 100644
--- a/src/amd/vulkan/radv_shader_info.c
+++ b/src/amd/vulkan/radv_shader_info.c
@@ -190,6 +190,33 @@ gather_intrinsic_store_deref_info(const nir_shader *nir,
 	}
 }
 
+static void
+gather_push_constant_info(const nir_shader *nir,
+			  const nir_intrinsic_instr *instr,
+			  struct radv_shader_info *info)
+{
+	nir_const_value *cval = nir_src_as_const_value(instr->src[0]);
+	int base = nir_intrinsic_base(instr);
+	int range = nir_intrinsic_range(instr);
+
+	if (!cval) {
+		info->has_indirect_push_constants = true;
+	} else {
+		uint32_t min = base + cval->u32[0];
+		uint32_t max = min + instr->num_components * 4;
+
+		info->max_push_constant_used =
+			MAX2(max, info->max_push_constant_used);
+		info->min_push_constant_used =
+			MIN2(min, info->min_push_constant_used);
+	}
+
+	if (instr->dest.ssa.bit_size != 32)
+		info->has_only_32bit_push_constants = false;
+
+	info->loads_push_constants = true;
+}
+
 static void
 gather_intrinsic_info(const nir_shader *nir, const nir_intrinsic_instr *instr,
 		      struct radv_shader_info *info)
@@ -243,7 +270,7 @@ gather_intrinsic_info(const nir_shader *nir, const nir_intrinsic_instr *instr,
 		info->uses_prim_id = true;
 		break;
 	case nir_intrinsic_load_push_constant:
-		info->loads_push_constants = true;
+		gather_push_constant_info(nir, instr, info);
 		break;
 	case nir_intrinsic_vulkan_resource_index:
 		info->desc_set_used_mask |= (1 << nir_intrinsic_desc_set(instr));
@@ -504,6 +531,14 @@ gather_xfb_info(const nir_shader *nir, struct radv_shader_info *info)
 	ralloc_free(xfb);
 }
 
+void
+radv_nir_shader_info_init(struct radv_shader_info *info)
+{
+	/* Assume that shaders only have 32-bit push constants by default. */
+	info->min_push_constant_used = UINT8_MAX;
+	info->has_only_32bit_push_constants = true;
+}
+
 void
 radv_nir_shader_info_pass(const struct nir_shader *nir,
 			  const struct radv_nir_compiler_options *options,
-- 
2.20.1