re PR lto/56168 (GCC seems to disregard -fno-builtin when compiling with LTO)

2013-02-04  Richard Guenther  <rguenther@suse.de>

	PR lto/56168
	* lto-symtab.c (lto_symtab_merge_decls_1): Make non-builtin
	node prevail as last resort.
	(lto_symtab_merge_decls): Remove guard on LTRANS here.
	(lto_symtab_prevailing_decl): Builtins are their own prevailing
	decl.

	lto/
	* lto.c (read_cgraph_and_symbols): Do not call lto_symtab_merge_decls
	or lto_fixup_decls at LTRANS time.

	* gcc.dg/lto/pr56168_0.c: New testcase.
	* gcc.dg/lto/pr56168_1.c: Likewise.

From-SVN: r195709

gcc/ChangeLog

+2013-02-04  Richard Guenther  <rguenther@suse.de>
+
+	PR lto/56168
+	* lto-symtab.c (lto_symtab_merge_decls_1): Make non-builtin
+	node prevail as last resort.
+	(lto_symtab_merge_decls): Remove guard on LTRANS here.
+	(lto_symtab_prevailing_decl): Builtins are their own prevailing
+	decl.
+
 2013-02-04  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/56113

gcc/lto-symtab.c

@@ -439,12 +439,12 @@ lto_symtab_merge_decls_1 (symtab_node first)
 		&& COMPLETE_TYPE_P (TREE_TYPE (e->symbol.decl)))
 	      prevailing = e;
 	}
-      /* For variables prefer the builtin if one is available.  */
+      /* For variables prefer the non-builtin if one is available.  */
       else if (TREE_CODE (prevailing->symbol.decl) == FUNCTION_DECL)
 	{
 	  for (e = first; e; e = e->symbol.next_sharing_asm_name)
 	    if (TREE_CODE (e->symbol.decl) == FUNCTION_DECL
-		&& DECL_BUILT_IN (e->symbol.decl))
+		&& !DECL_BUILT_IN (e->symbol.decl))
 	      {
 		prevailing = e;
 		break;
@@ -507,12 +507,6 @@ lto_symtab_merge_decls (void)
 {
   symtab_node node;
 
-  /* In ltrans mode we read merged cgraph, we do not really need to care
-     about resolving symbols again, we only need to replace duplicated declarations
-     read from the callgraph and from function sections.  */
-  if (flag_ltrans)
-    return;
-
   /* Populate assembler name hash.   */
   symtab_initialize_asm_name_hash ();
 
@@ -598,6 +592,11 @@ lto_symtab_prevailing_decl (tree decl)
   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_ABSTRACT (decl))
     return decl;
 
+  /* Likewise builtins are their own prevailing decl.  This preserves
+     non-builtin vs. builtin uses from compile-time.  */
+  if (TREE_CODE (decl) == FUNCTION_DECL && DECL_BUILT_IN (decl))
+    return decl;
+
   /* Ensure DECL_ASSEMBLER_NAME will not set assembler name.  */
   gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
 

gcc/lto/ChangeLog

+2013-02-04  Richard Guenther  <rguenther@suse.de>
+
+	PR lto/56168
+	* lto.c (read_cgraph_and_symbols): Do not call lto_symtab_merge_decls
+	or lto_fixup_decls at LTRANS time.
+
 2013-01-09  Jan Hubicka  <jh@suse.cz>
 
 	PR lto/45375

gcc/lto/lto.c

@@ -3033,16 +3033,22 @@ read_cgraph_and_symbols (unsigned nfiles, const char **fnames)
     fprintf (stderr, "Merging declarations\n");
 
   timevar_push (TV_IPA_LTO_DECL_MERGE);
-  /* Merge global decls.  */
-  lto_symtab_merge_decls ();
+  /* Merge global decls.  In ltrans mode we read merged cgraph, we do not
+     need to care about resolving symbols again, we only need to replace
+     duplicated declarations read from the callgraph and from function
+     sections.  */
+  if (!flag_ltrans)
+    {
+      lto_symtab_merge_decls ();
 
-  /* If there were errors during symbol merging bail out, we have no
-     good way to recover here.  */
-  if (seen_error ())
-    fatal_error ("errors during merging of translation units");
+      /* If there were errors during symbol merging bail out, we have no
+	 good way to recover here.  */
+      if (seen_error ())
+	fatal_error ("errors during merging of translation units");
 
-  /* Fixup all decls.  */
-  lto_fixup_decls (all_file_decl_data);
+      /* Fixup all decls.  */
+      lto_fixup_decls (all_file_decl_data);
+    }
   htab_delete (tree_with_vars);
   tree_with_vars = NULL;
   ggc_collect ();

gcc/testsuite/ChangeLog

+2013-02-04  Richard Guenther  <rguenther@suse.de>
+
+	PR lto/56168
+	* gcc.dg/lto/pr56168_0.c: New testcase.
+	* gcc.dg/lto/pr56168_1.c: Likewise.
+
 2013-02-02  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/50627

gcc/testsuite/gcc.dg/lto/pr56168_0.c

+/* { dg-lto-do run } */
+/* { dg-lto-options { { -flto -O -ffast-math -fno-builtin } } } */
+
+extern double pow(double, double);
+extern void abort (void);
+volatile double x = 1.0;
+int main(int argc, char **argv)
+{
+  double d1 = x;
+  double d2 = pow(d1, 1.0 / 3.0);
+  double d3 = d1 * d1;
+  if (d3 != 1.0 || d2 != 0.0)
+    abort ();
+  return 0;
+}

gcc/testsuite/gcc.dg/lto/pr56168_1.c

+/* { dg-options "-fno-lto" } */
+
+double __attribute__((noinline,noclone))
+pow (double x, double y) { return 0.0; }