From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 30 May 2017 07:51:58 +0000 (+0200)
Subject: backport: re PR c/77767 (Side-effect from VLA array parameters lost)
X-Git-Tag: releases/gcc-5.5.0~277
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ce18d8b570646cd8b6c63af45f789b08025d11c0;p=thirdparty%2Fgcc.git

backport: re PR c/77767 (Side-effect from VLA array parameters lost)

	Backported from mainline
	2016-12-21  Jakub Jelinek  <jakub@redhat.com>

	PR c/77767
	* c-decl.c (grokdeclarator): If *expr is non-NULL, append expression
	to *expr instead of overwriting it.

	* gcc.c-torture/execute/pr77767.c: New test.

From-SVN: r248635
---

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index bdc6b43856f5..caf2a72a8d0c 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,6 +1,12 @@
 2017-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-12-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/77767
+	* c-decl.c (grokdeclarator): If *expr is non-NULL, append expression
+	to *expr instead of overwriting it.
+
 	2016-08-12  Jakub Jelinek  <jakub@redhat.com>
 		    Martin Liska  <mliska@suse.cz>
 
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 0737c400e2ea..519a97917426 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -5409,11 +5409,21 @@ grokdeclarator (const struct c_declarator *declarator,
   if (TREE_CODE (type) == ERROR_MARK)
     return error_mark_node;
   if (expr == NULL)
-    expr = &expr_dummy;
+    {
+      expr = &expr_dummy;
+      expr_dummy = NULL_TREE;
+    }
   if (expr_const_operands == NULL)
     expr_const_operands = &expr_const_operands_dummy;
 
-  *expr = declspecs->expr;
+  if (declspecs->expr)
+    {
+      if (*expr)
+	*expr = build2 (COMPOUND_EXPR, TREE_TYPE (declspecs->expr), *expr,
+			declspecs->expr);
+      else
+	*expr = declspecs->expr;
+    }
   *expr_const_operands = declspecs->expr_const_operands;
 
   if (decl_context == FUNCDEF)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4969e956b5f0..ffd3164df19a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2017-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-12-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/77767
+	* gcc.c-torture/execute/pr77767.c: New test.
+
 	2016-12-13  Jakub Jelinek  <jakub@redhat.com>
 
 	PR ipa/77905
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr77767.c b/gcc/testsuite/gcc.c-torture/execute/pr77767.c
new file mode 100644
index 000000000000..21725a56bfe7
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr77767.c
@@ -0,0 +1,16 @@
+/* PR c/77767 */
+
+void
+foo (int a, int b[a++], int c, int d[c++])
+{
+  if (a != 2 || c != 2)
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+  int e[10];
+  foo (1, e, 1, e);
+  return 0;
+}