Merge branch 'PHP-7.4'

* PHP-7.4:
  Fixed bug #79412 (Opcache chokes and uses 100% CPU on specific script).

Author: dstogov

ext/opcache/Optimizer/zend_inference.c

@@ -1787,12 +1787,25 @@ static int zend_infer_ranges(const zend_op_array *op_array, zend_ssa *ssa) /* {{
 				}
 			} WHILE_WORKLIST_END();
 
-			/* Add all SCC entry variables into worklist for narrowing */
+			/* initialize missing ranges */
 			for (j = scc_var[scc]; j >= 0; j = next_scc_var[j]) {
 				if (!ssa->var_info[j].has_range) {
 					zend_inference_init_range(op_array, ssa, j, 1, ZEND_LONG_MIN, ZEND_LONG_MAX, 1);
-				} else if (ssa->vars[j].definition_phi &&
-				           ssa->vars[j].definition_phi->pi < 0) {
+					FOR_EACH_VAR_USAGE(j, ADD_SCC_VAR);
+				}
+			}
+
+			/* widening (second round) */
+			WHILE_WORKLIST(worklist, worklist_len, j) {
+				if (zend_ssa_range_widening(op_array, ssa, j, scc)) {
+					FOR_EACH_VAR_USAGE(j, ADD_SCC_VAR);
+				}
+			} WHILE_WORKLIST_END();
+
+			/* Add all SCC entry variables into worklist for narrowing */
+			for (j = scc_var[scc]; j >= 0; j = next_scc_var[j]) {
+				if (ssa->vars[j].definition_phi
+				 && ssa->vars[j].definition_phi->pi < 0) {
 					/* narrowing Phi functions first */
 					zend_ssa_range_narrowing(op_array, ssa, j, scc);
 				}

ext/opcache/tests/bug79412.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Bug #79412 (Opcache chokes and uses 100% CPU on specific script)
+--INI--
+opcache.enable=1
+opcache.optimization_level=-1
+--SKIPIF--
+<?php require_once('skipif.inc'); ?>
+--FILE--
+<?php
+$limitPerRun = 10;
+foreach ($foo as $bar) {
+    $count = 0;
+    foreach ($runs as $run) {
+        ++$count;
+        if ($count >= $limitPerRun) {
+            break;
+        }
+    }
+    foo($limitPerRun);
+}
+?>
+--EXPECTF--
+Warning: Undefined variable: foo in %s on line %d
+
+Warning: foreach() argument must be of type array|object, null given in %s on line %d