[committed] Fix OpenMP ICE with VLA in nested parallel regions (PR middle-end/39154)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

The following testcase ICEs with --enable-checking and segfaults at runtime
with --enable-checking=release.  The problem is that if an outer parallel
region mentions a VLA in its clauses but the VLA is only referenced in inner
parallel region, we add early the pointer replacement var for it, but
without GOVD_SEEN and nothing afterwards sets the GOVD_SEEN bit on it.
Which means it is removed from the outer parallel clauses and thus
uninitialized.

Fixed thusly, bootstrapped/regtested on x86_64-linux, committed to trunk.

2009-02-11  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/39154
	* gimplify.c (omp_notice_variable): If adding GOVD_SEEN
	bit to variable length decl's flags, add it also to its
	pointer replacement variable.

	* testsuite/libgomp.c/pr39154.c: New test.

--- gcc/gimplify.c.jj	2009-02-11 19:32:53.000000000 +0100
+++ gcc/gimplify.c	2009-02-11 21:34:42.000000000 +0100
@@ -5308,6 +5308,20 @@ omp_notice_variable (struct gimplify_omp
       goto do_outer;
     }
 
+  if ((n->value & (GOVD_SEEN | GOVD_LOCAL)) == 0
+      && (flags & (GOVD_SEEN | GOVD_LOCAL)) == GOVD_SEEN
+      && DECL_SIZE (decl)
+      && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
+    {
+      splay_tree_node n2;
+      tree t = DECL_VALUE_EXPR (decl);
+      gcc_assert (TREE_CODE (t) == INDIRECT_REF);
+      t = TREE_OPERAND (t, 0);
+      gcc_assert (DECL_P (t));
+      n2 = splay_tree_lookup (ctx->variables, (splay_tree_key) t);
+      n2->value |= GOVD_SEEN;
+    }
+
   shared = ((flags | n->value) & GOVD_SHARED) != 0;
   ret = lang_hooks.decls.omp_disregard_value_expr (decl, shared);
 
--- libgomp/testsuite/libgomp.c/pr39154.c.jj	2009-02-11 21:08:25.000000000 +0100
+++ libgomp/testsuite/libgomp.c/pr39154.c	2009-02-11 21:36:01.000000000 +0100
@@ -0,0 +1,105 @@
+/* PR middle-end/39154 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -std=gnu99" } */
+
+extern void abort (void);
+
+int n = 20;
+
+int
+main (void)
+{
+  int a[n], b[n][n];
+
+#pragma omp parallel for
+    for (int i = 0; i < n; i++)
+      {
+	a[i] = i + 1;
+#pragma omp parallel for
+	for (int j = 0; j < n; j++)
+	  b[i][j] = a[i];
+      }
+
+  for (int i = 0; i < n; i++)
+    {
+      for (int j = 0; j < n; j++)
+	if (b[i][j] != i + 1)
+	  abort ();
+      if (a[i] != i + 1)
+	abort ();
+    }
+
+#pragma omp parallel for shared (n, a, b)
+    for (int i = 0; i < n; i++)
+      {
+	a[i] = i + 3;
+#pragma omp parallel for
+	for (int j = 0; j < n; j++)
+	  b[i][j] = a[i];
+      }
+
+  for (int i = 0; i < n; i++)
+    {
+      for (int j = 0; j < n; j++)
+	if (b[i][j] != i + 3)
+	  abort ();
+      if (a[i] != i + 3)
+	abort ();
+    }
+
+#pragma omp parallel for
+    for (int i = 0; i < n; i++)
+      {
+	a[i] = i + 5;
+#pragma omp parallel for shared (n, a, b)
+	for (int j = 0; j < n; j++)
+	  b[i][j] = a[i];
+      }
+
+  for (int i = 0; i < n; i++)
+    {
+      for (int j = 0; j < n; j++)
+	if (b[i][j] != i + 5)
+	  abort ();
+      if (a[i] != i + 5)
+	abort ();
+    }
+
+#pragma omp parallel for shared (n, a, b)
+    for (int i = 0; i < n; i++)
+      {
+	a[i] = i + 7;
+#pragma omp parallel for shared (n, a, b)
+	for (int j = 0; j < n; j++)
+	  b[i][j] = a[i];
+      }
+
+  for (int i = 0; i < n; i++)
+    {
+      for (int j = 0; j < n; j++)
+	if (b[i][j] != i + 7)
+	  abort ();
+      if (a[i] != i + 7)
+	abort ();
+    }
+
+#pragma omp parallel for private (a, b)
+    for (int i = 0; i < n; i++)
+      {
+	a[i] = i + 1;
+#pragma omp parallel for
+	for (int j = 0; j < n; j++)
+	  b[i][j] = a[i];
+      }
+
+#pragma omp parallel for private (a, b)
+    for (int i = 0; i < n; i++)
+      {
+	a[i] = i + 1;
+#pragma omp parallel for private (b)
+	for (int j = 0; j < n; j++)
+	  b[i][j] = a[i];
+      }
+
+  return 0;
+}

	Jakub