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Re: [PATCH] PR64979: S/390: Fix setup of overflow area pointer in va_start


On Mon, Feb 09, 2015 at 01:05:23PM +0100, Jakub Jelinek wrote:
> As you can see, the updated testcase fails even on x86_64-linux.

Here is an updated patch that succeeds even on i686-linux.

2015-02-09  Jakub Jelinek  <jakub@redhat.com>

	PR target/64979
	* tree-stdarg.c (pass_stdarg::execute): Scan phi node args for
	va_list escapes.

	* gcc.dg/tree-ssa/stdarg-7.c: New test.
	* gcc.c-torture/execute/pr64979.c: New test.

--- gcc/tree-stdarg.c.jj	2015-01-09 21:59:44.000000000 +0100
+++ gcc/tree-stdarg.c	2015-02-09 13:14:43.880406573 +0100
@@ -856,22 +856,23 @@ pass_stdarg::execute (function *fun)
       /* For va_list_simple_ptr, we have to check PHI nodes too.  We treat
 	 them as assignments for the purpose of escape analysis.  This is
 	 not needed for non-simple va_list because virtual phis don't perform
-	 any real data movement.  */
-      if (va_list_simple_ptr)
+	 any real data movement.  Also, check PHI nodes for taking address of
+	 the va_list vars.  */
+      tree lhs, rhs;
+      use_operand_p uop;
+      ssa_op_iter soi;
+
+      for (gphi_iterator i = gsi_start_phis (bb); !gsi_end_p (i);
+	   gsi_next (&i))
 	{
-	  tree lhs, rhs;
-	  use_operand_p uop;
-	  ssa_op_iter soi;
+	  gphi *phi = i.phi ();
+	  lhs = PHI_RESULT (phi);
 
-	  for (gphi_iterator i = gsi_start_phis (bb); !gsi_end_p (i);
-	       gsi_next (&i))
-	    {
-	      gphi *phi = i.phi ();
-	      lhs = PHI_RESULT (phi);
-
-	      if (virtual_operand_p (lhs))
-		continue;
+	  if (virtual_operand_p (lhs))
+	    continue;
 
+	  if (va_list_simple_ptr)
+	    {
 	      FOR_EACH_PHI_ARG (uop, phi, soi, SSA_OP_USE)
 		{
 		  rhs = USE_FROM_PTR (uop);
@@ -894,6 +895,22 @@ pass_stdarg::execute (function *fun)
 		    }
 		}
 	    }
+
+	  for (unsigned j = 0; !va_list_escapes
+			       && j < gimple_phi_num_args (phi); ++j)
+	    if ((!va_list_simple_ptr
+		 || TREE_CODE (gimple_phi_arg_def (phi, j)) != SSA_NAME)
+		&& walk_tree (gimple_phi_arg_def_ptr (phi, j),
+			      find_va_list_reference, &wi, NULL))
+	      {
+		if (dump_file && (dump_flags & TDF_DETAILS))
+		  {
+		    fputs ("va_list escapes in ", dump_file);
+		    print_gimple_stmt (dump_file, phi, 0, dump_flags);
+		    fputc ('\n', dump_file);
+		  }
+		va_list_escapes = true;
+	      }
 	}
 
       for (gimple_stmt_iterator i = gsi_start_bb (bb);
@@ -916,8 +933,8 @@ pass_stdarg::execute (function *fun)
 
 	  if (is_gimple_assign (stmt))
 	    {
-	      tree lhs = gimple_assign_lhs (stmt);
-	      tree rhs = gimple_assign_rhs1 (stmt);
+	      lhs = gimple_assign_lhs (stmt);
+	      rhs = gimple_assign_rhs1 (stmt);
 
 	      if (va_list_simple_ptr)
 		{
--- gcc/testsuite/gcc.dg/tree-ssa/stdarg-7.c.jj	2015-02-09 12:54:44.222284401 +0100
+++ gcc/testsuite/gcc.dg/tree-ssa/stdarg-7.c	2015-02-09 12:58:10.406875647 +0100
@@ -0,0 +1,22 @@
+/* PR target/64979 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-stdarg" } */
+
+#include <stdarg.h>
+
+void bar (int x, va_list *ap);
+
+void
+foo (int x, ...)
+{
+  va_list ap;
+  int n;
+
+  va_start (ap, x);
+  n = va_arg (ap, int);
+  bar (x, (va_list *) ((n == 0) ? ((void *) 0) : &ap));
+  va_end (ap);
+}
+
+/* { dg-final { scan-tree-dump "foo: va_list escapes 1, needs to save all GPR units and all FPR units" "stdarg" } } */
+/* { dg-final { cleanup-tree-dump "stdarg" } } */
--- gcc/testsuite/gcc.c-torture/execute/pr64979.c.jj	2015-02-09 12:54:01.867984625 +0100
+++ gcc/testsuite/gcc.c-torture/execute/pr64979.c	2015-02-09 13:08:17.458818847 +0100
@@ -0,0 +1,36 @@
+/* PR target/64979 */
+
+#include <stdarg.h>
+
+void __attribute__((noinline, noclone))
+bar (int x, va_list *ap)
+{
+  if (ap)
+    {
+      int i;
+      for (i = 0; i < 10; i++)
+	if (i != va_arg (*ap, int))
+	  __builtin_abort ();
+      if (va_arg (*ap, double) != 0.5)
+	__builtin_abort ();
+    }
+}
+
+void __attribute__((noinline, noclone))
+foo (int x, ...)
+{
+  va_list ap;
+  int n;
+
+  va_start (ap, x);
+  n = va_arg (ap, int);
+  bar (x, (va_list *) ((n == 0) ? ((void *) 0) : &ap));
+  va_end (ap);
+}
+
+int
+main ()
+{
+  foo (100, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0.5);
+  return 0;
+}


	Jakub


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