Merge branch 'PHP-8.0'

* PHP-8.0:
  Fix phi use chain management when renaming variable

Author: nikic

ext/opcache/Optimizer/ssa_integrity.c

@@ -287,8 +287,9 @@ int ssa_verify_integrity(zend_op_array *op_array, zend_ssa *ssa, const char *ext
 
 	/* Phis */
 	FOREACH_PHI(phi) {
-		int source;
-		FOREACH_PHI_SOURCE(phi, source) {
+		unsigned num_sources = NUM_PHI_SOURCES(phi);
+		for (i = 0; i < num_sources; i++) {
+			int source = phi->sources[i];
 			if (source < 0) {
 				FAIL(VARFMT " negative source\n", VAR(phi->ssa_var));
 			}
@@ -298,7 +299,16 @@ int ssa_verify_integrity(zend_op_array *op_array, zend_ssa *ssa, const char *ext
 			if (ssa->vars[source].var != ssa->vars[phi->ssa_var].var) {
 				FAIL(VARFMT " source of phi for " VARFMT "\n", VAR(source), VAR(phi->ssa_var));
 			}
-		} FOREACH_PHI_SOURCE_END();
+			if (phi->use_chains[i]) {
+				int j;
+				for (j = i + 1; j < num_sources; j++) {
+					if (phi->sources[j] == source && phi->use_chains[j]) {
+						FAIL("use chain for source " VARFMT " of phi " VARFMT
+							" at %d despite earlier use\n", VAR(source), VAR(phi->ssa_var), j);
+					}
+				}
+			}
+		}
 		if (ssa->vars[phi->ssa_var].definition_phi != phi) {
 			FAIL(VARFMT " does not define this phi\n", VAR(phi->ssa_var));
 		}

ext/opcache/Optimizer/zend_ssa.c

@@ -1319,11 +1319,7 @@ static inline void zend_ssa_remove_phi_source(zend_ssa *ssa, zend_ssa_phi *phi,
 	for (j = 0; j < predecessors_count; j++) {
 		if (phi->sources[j] == var_num) {
 			if (j < pred_offset) {
-				if (next_phi == NULL) {
-					next_phi = phi->use_chains[pred_offset];
-				} else {
-					ZEND_ASSERT(phi->use_chains[pred_offset] == NULL);
-				}
+				ZEND_ASSERT(next_phi == NULL);
 			} else if (j >= pred_offset) {
 				phi->use_chains[j] = next_phi;
 			}
@@ -1612,6 +1608,8 @@ void zend_ssa_rename_var_uses(zend_ssa *ssa, int old, int new, zend_bool update_
 						new_var->phi_use_chain = phi;
 					}
 					after_first_new_source = 1;
+				} else {
+					phi->use_chains[j] = NULL;
 				}
 			}
 		}

ext/opcache/tests/phi_use_chain.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Check that phi use chains are correctly maintained when removing blocks
+--FILE--
+<?php
+
+function test(array $adapters) {
+    foreach ($adapters as $adapter) {
+        if (\in_array('cli-server', ['cli', 'phpdbg'], true) && $adapter instanceof stdClass && !\filter_var('1', \FILTER_VALIDATE_BOOLEAN)) {
+            continue;
+        }
+
+        $adapters[] = $adapter;
+    }
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===