Eliminate useless exception checks

Author: dstogov

ext/opcache/Optimizer/zend_inference.c

@@ -4312,7 +4312,8 @@ int zend_may_throw_ex(const zend_op *opline, const zend_ssa_op *ssa_op, const ze
 			}
 		}
 	} else if (opline->op1_type & (IS_TMP_VAR|IS_VAR)) {
-		if (t1 & (MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_ARRAY_OF_OBJECT|MAY_BE_ARRAY_OF_RESOURCE|MAY_BE_ARRAY_OF_ARRAY)) {
+		if ((t1 & MAY_BE_RC1)
+		 && (t1 & (MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_ARRAY_OF_OBJECT|MAY_BE_ARRAY_OF_RESOURCE|MAY_BE_ARRAY_OF_ARRAY))) {
 			switch (opline->opcode) {
 				case ZEND_CASE:
 				case ZEND_CASE_STRICT:
@@ -4350,7 +4351,8 @@ int zend_may_throw_ex(const zend_op *opline, const zend_ssa_op *ssa_op, const ze
 			}
 		}
 	} else if (opline->op2_type & (IS_TMP_VAR|IS_VAR)) {
-		if (t2 & (MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_ARRAY_OF_OBJECT|MAY_BE_ARRAY_OF_RESOURCE|MAY_BE_ARRAY_OF_ARRAY)) {
+		if ((t2 & MAY_BE_RC1)
+		 && (t2 & (MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_ARRAY_OF_OBJECT|MAY_BE_ARRAY_OF_RESOURCE|MAY_BE_ARRAY_OF_ARRAY))) {
 			switch (opline->opcode) {
 				case ZEND_ASSIGN:
 					break;

ext/opcache/jit/zend_jit_trace.c

@@ -3765,9 +3765,11 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 									((op1_info & MAY_BE_UNDEF) != 0 &&
 										opline->opcode == ZEND_FETCH_DIM_R) ||
 									((opline->op1_type & (IS_TMP_VAR|IS_VAR)) != 0 &&
+										(op1_info & MAY_BE_RC1) &&
 										(op1_info & (MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_ARRAY_OF_OBJECT|MAY_BE_ARRAY_OF_RESOURCE|MAY_BE_ARRAY_OF_ARRAY)) != 0) ||
 									(op2_info & MAY_BE_UNDEF) != 0 ||
 									((opline->op2_type & (IS_TMP_VAR|IS_VAR)) != 0 &&
+										(op2_info & MAY_BE_RC1) &&
 										(op2_info & (MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_ARRAY_OF_OBJECT|MAY_BE_ARRAY_OF_RESOURCE|MAY_BE_ARRAY_OF_ARRAY)) != 0)))) {
 							goto jit_failure;
 						}

ext/opcache/jit/zend_jit_x86.dasc

@@ -10595,7 +10595,7 @@ static int zend_jit_isset_isempty_dim(dasm_State **Dst, const zend_op *opline, c
 		if (exit_addr
 		 && !(op1_info & ((MAY_BE_ANY|MAY_BE_UNDEF)-MAY_BE_ARRAY))
 		 && !may_throw
-		 && !(opline->op1_type & (IS_TMP_VAR|IS_VAR))
+		 && (!(opline->op1_type & (IS_TMP_VAR|IS_VAR)) || (op1_info & AVOID_REFCOUNTING))
 		 && (!(opline->op2_type & (IS_TMP_VAR|IS_VAR)) || !(op2_info & ((MAY_BE_ANY|MAY_BE_UNDEF)-MAY_BE_LONG)))) {
 			if (smart_branch_opcode == ZEND_JMPNZ) {
 				found_exit_addr = exit_addr;