re PR c++/20995 (ICE in const_binop, at fold-const.c:1391)

	PR c++/20995
	Partial backport from mainline.
	2004-09-27  Mark Mitchell  <mark@codesourcery.com>
	* tree.c (fold_if_not_in_template): New function.
	* cp-tree.h (fold_if_not_in_template): Prototype here.
	* call.c (build_conditional_expr): Use fold_if_not_in_template.
	* typeck.c (build_binary_op): Likewise.

	* g++.dg/opt/pr20995-1.C: New test case.

Co-Authored-By: Mark Mitchell <mark@codesourcery.com>
From-SVN: r98736

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 8b7d0b97d57c8339179d7fbed60ec4957eac6bf4..2622d073203bb057ce1164fa9eb1ea2505e666fa 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,14 @@
+2005-04-25  Roger Sayle  <roger@eyesopen.com>
+           Mark Mitchell  <mark@codesourcery.com>
+
+       PR c++/20995
+       Partial backport from mainline.
+       2004-09-27  Mark Mitchell  <mark@codesourcery.com>
+       * tree.c (fold_if_not_in_template): New function.
+       * cp-tree.h (fold_if_not_in_template): Prototype here.
+       * call.c (build_conditional_expr): Use fold_if_not_in_template.
+       * typeck.c (build_binary_op): Likewise.
+
 2005-04-16  Mark Mitchell  <mark@codesourcery.com>
 
        PR c++/21025

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 968bd45fc268d12015e27a3aa87402399cef2a14..14b877cc415f78a9a7b1afa0f5919f38b60999d3 100644 (file)
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -1,6 +1,6 @@
 /* Functions related to invoking methods and overloaded functions.
    Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 
-   1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
    Contributed by Michael Tiemann (tiemann@cygnus.com) and
    modified by Brendan Kehoe (brendan@cygnus.com).
 
@@ -3278,7 +3278,8 @@ build_conditional_expr (tree arg1, tree arg2, tree arg3)
     }
 
  valid_operands:
-  result = fold (build (COND_EXPR, result_type, arg1, arg2, arg3));
+  result = fold_if_not_in_template (build (COND_EXPR, result_type,
+                                          arg1, arg2, arg3));
   /* We can't use result_type below, as fold might have returned a
      throw_expr.  */
 

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index bcb63b865870d802a4ea1e92043fab7453bbfa0f..9bf76bc008ff736eeeb56abb192b4b32784be707 100644 (file)
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -1,6 +1,6 @@
 /* Definitions for C++ parsing and type checking.
    Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-   2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
    Contributed by Michael Tiemann (tiemann@cygnus.com)
 
 This file is part of GCC.
@@ -4194,6 +4194,7 @@ extern int cp_cannot_inline_tree_fn (tree*);
 extern tree cp_add_pending_fn_decls (void*,tree);
 extern int cp_is_overload_p (tree);
 extern int cp_auto_var_in_fn_p (tree,tree);
+extern tree fold_if_not_in_template (tree);
 extern tree cp_copy_res_decl_for_inlining (tree, tree, tree, void*,
                                                   int*, tree);
 

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 2f078d145b4855079418383a52bacaf5c1560482..c64b4b134c805c2df405d82524933a2bf36e70c0 100644 (file)
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -1,6 +1,6 @@
 /* Language-dependent node constructors for parse phase of GNU compiler.
    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
    Hacked by Michael Tiemann (tiemann@cygnus.com)
 
 This file is part of GCC.
@@ -2526,6 +2526,19 @@ stabilize_init (tree init, tree *initp)
   return true;
 }
 
+/* Like "fold", but should be used whenever we might be processing the
+   body of a template.  */
+
+tree
+fold_if_not_in_template (tree expr)
+{
+  /* In the body of a template, there is never any need to call
+     "fold".  We will call fold later when actually instantiating the
+     template.  Integral constant expressions in templates will be
+     evaluated via fold_non_dependent_expr, as necessary.  */
+  return (processing_template_decl ? expr : fold (expr));
+}
+
 \f
 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
 /* Complain that some language-specific thing hanging off a tree

diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 648f95f3596c5a5db3d8a2ff24d33388810f73ef..634ca6685fbf1a4bd3bd37500cd6e1aa1f5c8459 100644 (file)
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -1,6 +1,6 @@
 /* Build expressions with type checking for C++ compiler.
    Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
    Hacked by Michael Tiemann (tiemann@cygnus.com)
 
 This file is part of GCC.
@@ -3458,7 +3458,7 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
     tree result = build (resultcode, build_type, op0, op1);
     tree folded;
 
-    folded = fold (result);
+    folded = fold_if_not_in_template (result);
     if (folded == result)
       TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1);
     if (final_type != 0)

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 110fb3ab4deb0ec777e69f84adf6dad30c5a7cb6..6a0ee4dec07cbeed58efc8741eb5a0832f6d59f9 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2005-04-25  Roger Sayle  <roger@eyesopen.com>
+
+       PR c++/20995
+       * g++.dg/opt/pr20995-1.C: New test case.
+
 2005-04-16  Mark Mitchell  <mark@codesourcery.com>
 
        PR c++/21025

diff --git a/gcc/testsuite/g++.dg/opt/pr20995-1.C b/gcc/testsuite/g++.dg/opt/pr20995-1.C
new file mode 100644 (file)
index 0000000..aa96896
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr20995-1.C
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+template<int N> void foo()
+{
+    double d = (N ? 0.0 : 0) + 1;
+}
+