Remove separate valid_T set

Rather than keeping track of a separate valid_T set (which must
always be in sync with map_T), use a dummy value in map_T to
denote unallocated temporaries.

Author: nikic

Zend/Optimizer/optimize_temp_vars_5.c

@@ -27,6 +27,7 @@
 #include "zend_vm.h"
 #include "zend_bitset.h"
 
+#define INVALID_VAR ((uint32_t)-1)
 #define GET_AVAILABLE_T()					\
 	for (i = 0; i < T; i++) {				\
 		if (!zend_bitset_in(taken_T, i)) {	\
@@ -45,7 +46,6 @@ void zend_optimize_temporary_variables(zend_op_array *op_array, zend_optimizer_c
 	uint32_t bitset_len;
 	zend_bitset taken_T;	/* T index in use */
 	zend_op **start_of_T;	/* opline where T is first used */
-	zend_bitset valid_T;	/* Is the map_T valid */
 	int *map_T;				/* Map's the T to its new index */
 	zend_op *opline, *end;
 	int currT;
@@ -56,8 +56,8 @@ void zend_optimize_temporary_variables(zend_op_array *op_array, zend_optimizer_c
 	bitset_len = zend_bitset_len(T);
 	taken_T = (zend_bitset) zend_arena_alloc(&ctx->arena, bitset_len * ZEND_BITSET_ELM_SIZE);
 	start_of_T = (zend_op **) zend_arena_alloc(&ctx->arena, T * sizeof(zend_op *));
-	valid_T = (zend_bitset) zend_arena_alloc(&ctx->arena, bitset_len * ZEND_BITSET_ELM_SIZE);
 	map_T = (int *) zend_arena_alloc(&ctx->arena, T * sizeof(int));
+	memset(map_T, 0xff, T * sizeof(int));
 
 	end = op_array->opcodes;
 	opline = &op_array->opcodes[op_array->last - 1];
@@ -70,7 +70,6 @@ void zend_optimize_temporary_variables(zend_op_array *op_array, zend_optimizer_c
 		opline--;
 	}
 
-	zend_bitset_clear(valid_T, bitset_len);
 	zend_bitset_clear(taken_T, bitset_len);
 
 	end = op_array->opcodes;
@@ -90,15 +89,14 @@ void zend_optimize_temporary_variables(zend_op_array *op_array, zend_optimizer_c
 				max = MAX(max, var + num);
 				var = var + 1;
 				map_T[currT] = var;
-				zend_bitset_incl(valid_T, currT);
 				zend_bitset_incl(taken_T, var);
 				opline->op1.var = NUM_VAR(var + offset);
 				while (num > 1) {
 					num--;
 					zend_bitset_incl(taken_T, var + num);
 				}
 			} else {
-				if (!zend_bitset_in(valid_T, currT)) {
+				if (map_T[currT] == INVALID_VAR) {
 					int use_new_var = 0;
 
 					/* Code in "finally" blocks may modify temporary variables.
@@ -132,29 +130,26 @@ void zend_optimize_temporary_variables(zend_op_array *op_array, zend_optimizer_c
 						GET_AVAILABLE_T();
 					}
 					map_T[currT] = i;
-					zend_bitset_incl(valid_T, currT);
 				}
 				opline->op1.var = NUM_VAR(map_T[currT] + offset);
 			}
 		}
 
 		if ((opline->op2_type & (IS_VAR | IS_TMP_VAR))) {
 			currT = VAR_NUM(opline->op2.var) - offset;
-			if (!zend_bitset_in(valid_T, currT)) {
+			if (map_T[currT] == INVALID_VAR) {
 				GET_AVAILABLE_T();
 				map_T[currT] = i;
-				zend_bitset_incl(valid_T, currT);
 			}
 			opline->op2.var = NUM_VAR(map_T[currT] + offset);
 		}
 
 		if (opline->result_type & (IS_VAR | IS_TMP_VAR)) {
 			currT = VAR_NUM(opline->result.var) - offset;
-			if (!zend_bitset_in(valid_T, currT)) {
+			if (map_T[currT] == INVALID_VAR) {
 				/* As a result of DCE, an opcode may have an unused result. */
 				GET_AVAILABLE_T();
 				map_T[currT] = i;
-				zend_bitset_incl(valid_T, currT);
 			}
 			opline->result.var = NUM_VAR(map_T[currT] + offset);
 			if (start_of_T[currT] == opline) {