radeonsi: split out interpolation input selection

This is prep work for using it in the interpolation code
later.

Also add storage for the input interpolation mode so we
can pick it up later.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 38 insertions, 26 deletions

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 77ba9c9e0a1..5a3de96a846 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -836,6 +836,35 @@ static LLVMValueRef fetch_input_gs(
 				tgsi2llvmtype(bld_base, type), "");
 }
 
+static int lookup_interp_param_index(unsigned interpolate, unsigned location)
+{
+	switch (interpolate) {
+	case TGSI_INTERPOLATE_CONSTANT:
+		return 0;
+
+	case TGSI_INTERPOLATE_LINEAR:
+		if (location == TGSI_INTERPOLATE_LOC_SAMPLE)
+			return SI_PARAM_LINEAR_SAMPLE;
+		else if (location == TGSI_INTERPOLATE_LOC_CENTROID)
+			return SI_PARAM_LINEAR_CENTROID;
+		else
+			return SI_PARAM_LINEAR_CENTER;
+		break;
+	case TGSI_INTERPOLATE_COLOR:
+	case TGSI_INTERPOLATE_PERSPECTIVE:
+		if (location == TGSI_INTERPOLATE_LOC_SAMPLE)
+			return SI_PARAM_PERSP_SAMPLE;
+		else if (location == TGSI_INTERPOLATE_LOC_CENTROID)
+			return SI_PARAM_PERSP_CENTROID;
+		else
+			return SI_PARAM_PERSP_CENTER;
+		break;
+	default:
+		fprintf(stderr, "Warning: Unhandled interpolation mode.\n");
+		return -1;
+	}
+}
+
 static void declare_input_fs(
 	struct radeon_llvm_context *radeon_bld,
 	unsigned input_index,
@@ -850,7 +879,8 @@ static void declare_input_fs(
 	LLVMTypeRef input_type = LLVMFloatTypeInContext(gallivm->context);
 	LLVMValueRef main_fn = radeon_bld->main_fn;
 
-	LLVMValueRef interp_param;
+	LLVMValueRef interp_param = NULL;
+	int interp_param_idx;
 	const char * intr_name;
 
 	/* This value is:
@@ -899,31 +929,13 @@ static void declare_input_fs(
 	attr_number = lp_build_const_int32(gallivm,
 					   shader->ps_input_param_offset[input_index]);
 
-	switch (decl->Interp.Interpolate) {
-	case TGSI_INTERPOLATE_CONSTANT:
-		interp_param = 0;
-		break;
-	case TGSI_INTERPOLATE_LINEAR:
-		if (decl->Interp.Location == TGSI_INTERPOLATE_LOC_SAMPLE)
-			interp_param = LLVMGetParam(main_fn, SI_PARAM_LINEAR_SAMPLE);
-		else if (decl->Interp.Location == TGSI_INTERPOLATE_LOC_CENTROID)
-			interp_param = LLVMGetParam(main_fn, SI_PARAM_LINEAR_CENTROID);
-		else
-			interp_param = LLVMGetParam(main_fn, SI_PARAM_LINEAR_CENTER);
-		break;
-	case TGSI_INTERPOLATE_COLOR:
-	case TGSI_INTERPOLATE_PERSPECTIVE:
-		if (decl->Interp.Location == TGSI_INTERPOLATE_LOC_SAMPLE)
-			interp_param = LLVMGetParam(main_fn, SI_PARAM_PERSP_SAMPLE);
-		else if (decl->Interp.Location == TGSI_INTERPOLATE_LOC_CENTROID)
-			interp_param = LLVMGetParam(main_fn, SI_PARAM_PERSP_CENTROID);
-		else
-			interp_param = LLVMGetParam(main_fn, SI_PARAM_PERSP_CENTER);
-		break;
-	default:
-		fprintf(stderr, "Warning: Unhandled interpolation mode.\n");
+	shader->ps_input_interpolate[input_index] = decl->Interp.Interpolate;
+	interp_param_idx = lookup_interp_param_index(decl->Interp.Interpolate,
+						     decl->Interp.Location);
+	if (interp_param_idx == -1)
 		return;
-	}
+	else if (interp_param_idx)
+		interp_param = LLVMGetParam(main_fn, interp_param_idx);
 
 	/* fs.constant returns the param from the middle vertex, so it's not
 	 * really useful for flat shading. It's meant to be used for custom
diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
index b52714d5abe..82e9c915965 100644
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -258,7 +258,7 @@ struct si_shader {
 	unsigned		nparam;
 	unsigned		vs_output_param_offset[PIPE_MAX_SHADER_OUTPUTS];
 	unsigned		ps_input_param_offset[PIPE_MAX_SHADER_INPUTS];
-
+	unsigned		ps_input_interpolate[PIPE_MAX_SHADER_INPUTS];
 	bool			uses_instanceid;
 	unsigned		nr_pos_exports;
 	unsigned		nr_param_exports;