radeonsi: use SI_MAX_IO_GENERIC instead of magic values

Tested-by: Dieter Nützel <Dieter@nuetzel-hh.de>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/drivers/radeonsi/si_shader.c

@@ -142,7 +142,7 @@ unsigned si_shader_io_get_unique_index(unsigned semantic_name, unsigned index)
 		assert(index <= 1);
 		return 2 + index;
 	case TGSI_SEMANTIC_GENERIC:
-		if (index <= 63-4)
+		if (index < SI_MAX_IO_GENERIC)
 			return 4 + index;
 
 		assert(!"invalid generic index");

src/gallium/drivers/radeonsi/si_shader.h

@@ -145,6 +145,11 @@ struct ac_shader_binary;
 
 #define SI_MAX_VS_OUTPUTS	40
 
+/* Shader IO unique indices are supported for TGSI_SEMANTIC_GENERIC with an
+ * index smaller than this.
+ */
+#define SI_MAX_IO_GENERIC       60
+
 /* SGPR user data indices */
 enum {
 	/* GFX9 merged shaders have RW_BUFFERS among the first 8 system SGPRs,

src/gallium/drivers/radeonsi/si_state_shaders.c

@@ -1843,7 +1843,7 @@ void si_init_shader_selector_async(void *job, int thread_index)
 				switch (name) {
 				case TGSI_SEMANTIC_GENERIC:
 					/* don't process indices the function can't handle */
-					if (index >= 60)
+					if (index >= SI_MAX_IO_GENERIC)
 						break;
 					/* fall through */
 				case TGSI_SEMANTIC_CLIPDIST:
@@ -2000,7 +2000,7 @@ static void *si_create_shader_selector(struct pipe_context *ctx,
 
 			case TGSI_SEMANTIC_GENERIC:
 				/* don't process indices the function can't handle */
-				if (index >= 60)
+				if (index >= SI_MAX_IO_GENERIC)
 					break;
 				/* fall through */
 			case TGSI_SEMANTIC_POSITION: