Fixed bug #80255

This was a copy&paste mistake, target_block was used where
follow_block was intended. Also update copy&paste mistakes in
the comments.

Author: nikic

NEWS

@@ -9,6 +9,9 @@ PHP                                                                        NEWS
 - IMAP:
   . Fixed bug #80239 (imap_rfc822_write_address() leaks memory). (cmb)
 
+- Opcache:
+  . Fixed bug #80255 (Opcache bug (bad condition result) in 8.0.0rc1). (Nikita)
+
 15 Oct 2020, PHP 8.0.0RC2
 
 - Core:

Zend/tests/bug80255.phpt

@@ -0,0 +1,24 @@
+--TEST--
+Bug #80255: Opcache bug (bad condition result) in 8.0.0rc1
+--FILE--
+<?php
+
+function test($a, $b, $c) {
+    do {
+        if ($a && !$b) {
+            break;
+        } else if ($b) {
+            echo "foo\n";
+        }
+        echo "bar\n";
+    } while ($c);
+    echo "baz\n";
+}
+
+test(true, true, false);
+
+?>
+--EXPECT--
+foo
+bar
+baz

ext/opcache/Optimizer/block_pass.c

@@ -1516,16 +1516,16 @@ static void zend_jmp_optimization(zend_basic_block *block, zend_op_array *op_arr
 				target = op_array->opcodes + follow_block->start;
 
 				if (target->opcode == ZEND_JMP) {
-					/* JMPZNZ(X, L1, L2), L1: JMP(L3) -> JMPZNZ(X, L3, L2) */
+					/* JMPZNZ(X, L1, L2), L2: JMP(L3) -> JMPZNZ(X, L1, L3) */
 					next = follow_block->successors[0];
 				} else if (target->opcode == ZEND_JMPNZ &&
 				           SAME_VAR(target->op1, last_op->op1)) {
-					/* JMPZNZ(X, L1, L2), L1: X = JMPNZ(X, L3) -> JMPZNZ(X, L1+1, L2) */
+					/* JMPZNZ(X, L1, L2), L2: X = JMPNZ(X, L3) -> JMPZNZ(X, L1, L3) */
 					next = follow_block->successors[0];
 				} else if ((target->opcode == ZEND_JMPZ || target->opcode == ZEND_JMPZNZ) &&
 				           SAME_VAR(target->op1, last_op->op1)) {
-					/* JMPZNZ(X, L1, L2), L1: JMPZ(X, L3) -> JMPZNZ(X, L3, L2) */
-					next = target_block->successors[1];
+					/* JMPZNZ(X, L1, L2), L2: JMPZ(X, L3) -> JMPZNZ(X, L1, L2+1) */
+					next = follow_block->successors[1];
 				} else {
 					break;
 				}