Reorder conditions to save one instruction in recursive return loop

Author: dstogov

ext/opcache/jit/zend_jit.c

@@ -2673,7 +2673,7 @@ static int zend_jit(const zend_op_array *op_array, zend_ssa *ssa, const zend_op
 									}
 								}
 							}
-						    if (!zend_jit_leave_func(&dasm_state, opline, op_array, NULL)) {
+						    if (!zend_jit_leave_func(&dasm_state, opline, op_array, NULL, NULL)) {
 								goto jit_failure;
 						    }
 						}

ext/opcache/jit/zend_jit_internal.h

@@ -331,6 +331,7 @@ typedef union _zend_jit_trace_stack {
 
 /* trace info flags */
 #define ZEND_JIT_TRACE_CHECK_INTERRUPT (1<<0)
+#define ZEND_JIT_TRACE_LOOP            (1<<1)
 
 typedef struct _zend_jit_trace_info {
 	uint32_t                  id;            /* trace id */

ext/opcache/jit/zend_jit_trace.c

@@ -3334,7 +3334,7 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 									}
 								}
 							}
-							if (!zend_jit_leave_func(&dasm_state, opline, op_array, p + 1)) {
+							if (!zend_jit_leave_func(&dasm_state, opline, op_array, p + 1, &zend_jit_traces[ZEND_JIT_TRACE_NUM])) {
 								goto jit_failure;
 							}
 						}
@@ -4046,7 +4046,10 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 		if (p->stop != ZEND_JIT_TRACE_STOP_RECURSIVE_RET) {
 			t->flags |= ZEND_JIT_TRACE_CHECK_INTERRUPT;
 		}
-		zend_jit_trace_end_loop(&dasm_state, 0, timeout_exit_addr); /* jump back to start of the trace loop */
+		if (!(t->flags & ZEND_JIT_TRACE_LOOP)) {
+			t->flags |= ZEND_JIT_TRACE_LOOP;
+			zend_jit_trace_end_loop(&dasm_state, 0, timeout_exit_addr); /* jump back to start of the trace loop */
+		}
 	} else if (p->stop == ZEND_JIT_TRACE_STOP_LINK) {
 		if (ra) {
 			/* Generate code for trace deoptimization */

ext/opcache/jit/zend_jit_x86.dasc

@@ -9572,7 +9572,7 @@ static int zend_jit_free_cv(dasm_State **Dst, const zend_op *opline, const zend_
 	return 1;
 }
 
-static int zend_jit_leave_func(dasm_State **Dst, const zend_op *opline, const zend_op_array *op_array, zend_jit_trace_rec *trace)
+static int zend_jit_leave_func(dasm_State **Dst, const zend_op *opline, const zend_op_array *op_array, zend_jit_trace_rec *trace, zend_jit_trace_info *trace_info)
 {
 	/* ZEND_CALL_FAKE_CLOSURE handled on slow path to eliminate check for ZEND_CALL_CLOSURE on fast path */
 	|	mov FCARG1d, dword [FP + offsetof(zend_execute_data, This.u1.type_info)]
@@ -9669,8 +9669,16 @@ static int zend_jit_leave_func(dasm_State **Dst, const zend_op *opline, const ze
 				return 0;
 			}
 			|	// TODO: exception handling ???
-			|	CMP_IP next_opline
-			|	jne &exit_addr
+			if (trace->op == ZEND_JIT_TRACE_END
+			 && trace->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_RET) {
+				trace_info->flags |= ZEND_JIT_TRACE_LOOP;
+				|	CMP_IP next_opline
+				|	je =>0 // LOOP
+				|	jmp &exit_addr
+			} else {
+				|	CMP_IP next_opline
+				|	jne &exit_addr
+			}
 
 			last_valid_opline = trace->opline;