intel/eu: Switch to a logical state stack

Instead of the state stack that's based on copying a dummy instruction
around, we start using a logical stack of brw_insn_states.  This uses a
bit less memory and is way less conceptually bogus.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/intel/compiler/brw_eu.h

@@ -46,6 +46,36 @@ extern "C" {
 
 #define BRW_EU_MAX_INSN_STACK 5
 
+struct brw_insn_state {
+   /* One of BRW_EXECUTE_* */
+   unsigned exec_size:3;
+
+   /* Group in units of channels */
+   unsigned group:5;
+
+   /* Compression control on gen4-5 */
+   bool compressed:1;
+
+   /* One of BRW_MASK_* */
+   unsigned mask_control:1;
+
+   bool saturate:1;
+
+   /* One of BRW_ALIGN_* */
+   unsigned access_mode:1;
+
+   /* One of BRW_PREDICATE_* */
+   enum brw_predicate predicate:4;
+
+   bool pred_inv:1;
+
+   /* Flag subreg.  Bottom bit is subreg, top bit is reg */
+   unsigned flag_subreg:2;
+
+   bool acc_wr_control:1;
+};
+
+
 /* A helper for accessing the last instruction emitted.  This makes it easy
  * to set various bits on an instruction without having to create temporary
  * variable and assign the emitted instruction to those.
@@ -62,8 +92,8 @@ struct brw_codegen {
 
    /* Allow clients to push/pop instruction state:
     */
-   brw_inst stack[BRW_EU_MAX_INSN_STACK];
-   brw_inst *current;
+   struct brw_insn_state stack[BRW_EU_MAX_INSN_STACK];
+   struct brw_insn_state *current;
 
    /** Whether or not the user wants automatic exec sizes
     *