tgsi: provide a way to encode memory qualifiers for SSBO

Each load/store on most hardware can specify what caching to do. Since
SSBO allows individual variables to also have separate caching modes,
allow loads/stores to have the qualifiers instead of attempting to
encode them in declarations.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/include/pipe/p_shader_tokens.h

@@ -572,7 +572,8 @@ struct tgsi_instruction
    unsigned Predicate  : 1;  /* BOOL */
    unsigned Label      : 1;
    unsigned Texture    : 1;
-   unsigned Padding    : 2;
+   unsigned Memory     : 1;
+   unsigned Padding    : 1;
 };
 
 /*
@@ -729,6 +730,19 @@ struct tgsi_dst_register
    unsigned Padding     : 6;
 };
 
+#define TGSI_MEMORY_COHERENT (1 << 0)
+#define TGSI_MEMORY_RESTRICT (1 << 1)
+#define TGSI_MEMORY_VOLATILE (1 << 2)
+
+/**
+ * Specifies the type of memory access to do for the LOAD/STORE instruction.
+ */
+struct tgsi_instruction_memory
+{
+   unsigned Qualifier : 3;  /* TGSI_MEMORY_ */
+   unsigned Padding   : 29;
+};
+
 
 #ifdef __cplusplus
 }