[4.1 PATCH] Do not automatically enable Tree-SRA for Ada

[Eric Botcazou <ebotcazou at adacore dot com>]

The problems that prompted the 4.0 patch
  http://gcc.gnu.org/ml/gcc-patches/2005-04/msg00646.html
are still present AFAICS as of today.

Bootstrapped/regtested on i586-suse-linux, 0 ACATS failures.  OK for 4.1 
branch?


2005-12-13  Eric Botcazou  <ebotcazou@adacore.com>

        PR ada/18659
        PR ada/18819
ada/
        * misc.c (tree_sra_requested): New global.
        (gnat_init_options): Detect -ftree-sra.
        (gnat_post_options): Enable Tree-SRA only if specifically requested.

gcc/
	* doc/invoke.texi (Optimize Options): Document that
	-ftree-sra is not automatically enabled for the Ada compiler.


-- 
Eric Botcazou

Index: ada/misc.c
===================================================================
--- ada/misc.c	(revision 107650)
+++ ada/misc.c	(working copy)
@@ -323,11 +323,15 @@ gnat_handle_option (size_t scode, const 
   return 1;
 }
 
+static bool tree_sra_requested = false;
+
 /* Initialize for option processing.  */
 
 static unsigned int
 gnat_init_options (unsigned int argc, const char **argv)
 {
+  int i;
+
   /* Initialize gnat_argv with save_argv size.  */
   gnat_argv = (char **) xmalloc ((argc + 1) * sizeof (argv[0]));
   gnat_argv[0] = xstrdup (argv[0]);     /* name of the command */
@@ -339,6 +343,16 @@ gnat_init_options (unsigned int argc, co
   /* Uninitialized really means uninitialized in Ada.  */
   flag_zero_initialized_in_bss = 0;
 
+  /* Find last option mentioning Tree-SRA.  */
+  for (i = argc - 1; i > 0; i--)
+    if (strcmp(argv[i], "-ftree-sra") == 0)
+      {
+	tree_sra_requested = true;
+	break;
+      }
+    else if (strcmp(argv[i], "-fno-tree-sra") == 0)
+      break;
+
   return CL_Ada;
 }
 
@@ -356,6 +370,11 @@ gnat_post_options (const char **pfilenam
 
   flag_tree_salias = 0;
 
+  /* Do not enable Tree-SRA unless specifically requested as it
+     is known to badly interact with some Ada constructs.  */
+  if (!tree_sra_requested)
+    flag_tree_sra = 0;
+
   return false;
 }
 
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi	(revision 107650)
+++ doc/invoke.texi	(working copy)
@@ -4363,6 +4363,10 @@ compilation time.
 @option{-O} also turns on @option{-fomit-frame-pointer} on machines
 where doing so does not interfere with debugging.
 
+@option{-O} doesn't turn on @option{-ftree-sra} for the Ada compiler.
+This option must be explicitly specified on the command line to be
+enabled for the Ada compiler.
+
 @item -O2
 @opindex O2
 Optimize even more.  GCC performs nearly all supported optimizations