Improve register allocator (give preference to loop variables).

Author: dstogov

ext/opcache/jit/zend_jit.c

@@ -964,7 +964,7 @@ static zend_lifetime_interval *zend_jit_sort_intervals(zend_lifetime_interval **
 		if (ival) {
 			if ((ival->range.start > last->range.start) ||
 			    (ival->range.start == last->range.start &&
-			     ((!ival->hint && last->hint) ||
+			     ((!ival->hint && last->hint && last->hint != ival) ||
 			      ival->range.end > last->range.end))) {
 				last->list_next = ival;
 				last = ival;
@@ -979,7 +979,7 @@ static zend_lifetime_interval *zend_jit_sort_intervals(zend_lifetime_interval **
 						break;
 					} else if ((ival->range.start < (*p)->range.start) ||
 					           (ival->range.start == (*p)->range.start &&
-					            ((ival->hint && !(*p)->hint) ||
+					            ((ival->hint && !(*p)->hint && ival->hint != *p) ||
 					             ival->range.end < (*p)->range.end))) {
 						ival->list_next = *p;
 						*p = ival;

ext/opcache/jit/zend_jit_trace.c

@@ -2641,12 +2641,26 @@ static zend_lifetime_interval** zend_jit_trace_allocate_registers(zend_jit_trace
 							    intervals[ssa->ops[line].op1_use] &&
 							    ssa->ops[line].op1_use_chain < 0 &&
 							    !ssa->vars[ssa->ops[line].op1_use].phi_use_chain) {
+
+								zend_ssa_phi *phi = ssa->vars[ssa->ops[line].op1_use].definition_phi;
+								if (phi &&
+								    intervals[phi->sources[1]] &&
+								    intervals[phi->sources[1]]->hint == intervals[ssa->ops[line].op1_use]) {
+									break;
+								}
 								zend_jit_add_hint(intervals, i, ssa->ops[line].op1_use);
 							} else if (opline->opcode != ZEND_SUB &&
 							    ssa->ops[line].op2_use >= 0 &&
 							    intervals[ssa->ops[line].op2_use] &&
 							    ssa->ops[line].op2_use_chain < 0 &&
 							    !ssa->vars[ssa->ops[line].op2_use].phi_use_chain) {
+
+								zend_ssa_phi *phi = ssa->vars[ssa->ops[line].op2_use].definition_phi;
+								if (phi &&
+								    intervals[phi->sources[1]] &&
+								    intervals[phi->sources[1]]->hint == intervals[ssa->ops[line].op2_use]) {
+									break;
+								}
 								zend_jit_add_hint(intervals, i, ssa->ops[line].op2_use);
 							}
 						}