Eliminate dead type stores

Author: dstogov

ext/opcache/jit/zend_jit.c

@@ -2246,7 +2246,7 @@ static int zend_jit(const zend_op_array *op_array, zend_ssa *ssa, const zend_op
 					} else if (ival->flags & ZREG_STORE) {
 						ZEND_ASSERT(ival->reg != ZREG_NONE);
 
-						if (!zend_jit_store_var(&dasm_state, ssa->var_info[phi->ssa_var].type, ssa->vars[phi->ssa_var].var, ival->reg)) {
+						if (!zend_jit_store_var(&dasm_state, ssa->var_info[phi->ssa_var].type, ssa->vars[phi->ssa_var].var, ival->reg, 1)) {
 							goto jit_failure;
 						}
 					}
@@ -2699,7 +2699,7 @@ static int zend_jit(const zend_op_array *op_array, zend_ssa *ssa, const zend_op
 						}
 						if (!zend_jit_qm_assign(&dasm_state, opline,
 								OP1_INFO(), op1_addr, op1_def_addr,
-								RES_INFO(), RES_REG_ADDR())) {
+								-1, RES_INFO(), RES_REG_ADDR())) {
 							goto jit_failure;
 						}
 						goto done;

ext/opcache/jit/zend_jit_internal.h

@@ -317,9 +317,10 @@ typedef union _zend_jit_trace_stack {
 	int32_t      ssa_var;
 	uint32_t     info;
 	struct {
-		uint8_t  type;
-		int8_t   reg;
-		uint16_t flags;
+		uint8_t type;     /* variable type (for type inference) */
+		uint8_t mem_type; /* stack slot type  (for eliminate dead type store) */
+		int8_t  reg;
+		uint8_t flags;
 	};
 } zend_jit_trace_stack;
 
@@ -329,6 +330,8 @@ typedef union _zend_jit_trace_stack {
 	(_stack)[_slot].info
 #define STACK_TYPE(_stack, _slot) \
 	(_stack)[_slot].type
+#define STACK_MEM_TYPE(_stack, _slot) \
+	(_stack)[_slot].mem_type
 #define STACK_REG(_stack, _slot) \
 	(_stack)[_slot].reg
 #define SET_STACK_VAR(_stack, _slot, _ssa_var) do { \
@@ -337,8 +340,12 @@ typedef union _zend_jit_trace_stack {
 #define SET_STACK_INFO(_stack, _slot, _info) do { \
 		(_stack)[_slot].info = _info; \
 	} while (0)
-#define SET_STACK_TYPE(_stack, _slot, _type) do { \
-		(_stack)[_slot].type = _type; \
+#define SET_STACK_TYPE(_stack, _slot, _type, _set_mem_type) do { \
+		uint8_t __type = (_type); \
+		(_stack)[_slot].type = __type; \
+		if (_set_mem_type) { \
+			(_stack)[_slot].mem_type = __type; \
+		} \
 		(_stack)[_slot].reg = ZREG_NONE; \
 		(_stack)[_slot].flags = 0; \
 	} while (0)