basic-block.h (CLEANUP_NO_INSN_DEL): Define it.

2002-05-23  David S. Miller  <davem@redhat.com>

	* basic-block.h (CLEANUP_NO_INSN_DEL): Define it.
	* cfgcleanup.c (cleanup_cfg): If it is set do not
	attempt to delete trivially dead insns.
	* except.c (finish_eh_generation): Pass it to cleanup_cfg.
	* toplev.c (rest_of_compilation): Document non-trivial aspect
	the RTL before optimize_save_area_alloca is run.

From-SVN: r53789

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9da36a9..d7334a9 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2002-05-23  David S. Miller  <davem@redhat.com>
+
+       * basic-block.h (CLEANUP_NO_INSN_DEL): Define it.
+       * cfgcleanup.c (cleanup_cfg): If it is set do not
+       attempt to delete trivially dead insns.
+       * except.c (finish_eh_generation): Pass it to cleanup_cfg.
+       * toplev.c (rest_of_compilation): Document non-trivial aspect
+       the RTL before optimize_save_area_alloca is run.
+
 2002-05-23  Neil Booth  <neil@daikokuya.demon.co.uk>
 
        * c-lex.c (indent_level): Remove.

diff --git a/gcc/basic-block.h b/gcc/basic-block.h
index cf0d13a..69ec122 100644 (file)
--- a/gcc/basic-block.h
+++ b/gcc/basic-block.h
@@ -595,6 +595,8 @@ enum update_life_extent
                                           notes.  */
 #define CLEANUP_UPDATE_LIFE    32      /* Keep life information up to date.  */
 #define CLEANUP_THREADING      64      /* Do jump threading.  */
+#define CLEANUP_NO_INSN_DEL    128     /* Do not try to delete trivially dead
+                                          insns.  */
 /* Flags for loop discovery.  */
 
 #define LOOP_TREE              1       /* Build loop hierarchy tree.  */

diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index d5f6de1..1e4056a 100644 (file)
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -1800,7 +1800,8 @@ cleanup_cfg (mode)
       changed = true;
       /* We've possibly created trivially dead code.  Cleanup it right
         now to introduce more oppurtunities for try_optimize_cfg.  */
-      if (!(mode & (CLEANUP_UPDATE_LIFE | CLEANUP_PRE_SIBCALL))
+      if (!(mode & (CLEANUP_NO_INSN_DEL
+                   | CLEANUP_UPDATE_LIFE | CLEANUP_PRE_SIBCALL))
          && !reload_completed)
        delete_trivially_dead_insns (get_insns(), max_reg_num ());
     }
@@ -1819,7 +1820,8 @@ cleanup_cfg (mode)
                                                 | PROP_LOG_LINKS))
            break;
        }
-      else if (!(mode & CLEANUP_PRE_SIBCALL) && !reload_completed)
+      else if (!(mode & (CLEANUP_NO_INSN_DEL | CLEANUP_PRE_SIBCALL))
+              && !reload_completed)
        {
          if (!delete_trivially_dead_insns (get_insns(), max_reg_num ()))
            break;

diff --git a/gcc/except.c b/gcc/except.c
index e1f32a5..ee6ee9f 100644 (file)
--- a/gcc/except.c
+++ b/gcc/except.c
@@ -2501,7 +2501,7 @@ finish_eh_generation ()
 
   rebuild_jump_labels (get_insns ());
   find_basic_blocks (get_insns (), max_reg_num (), 0);
-  cleanup_cfg (CLEANUP_PRE_LOOP);
+  cleanup_cfg (CLEANUP_PRE_LOOP | CLEANUP_NO_INSN_DEL);
 
   /* These registers are used by the landing pads.  Make sure they
      have been generated.  */
@@ -2524,7 +2524,7 @@ finish_eh_generation ()
   find_exception_handler_labels ();
   rebuild_jump_labels (get_insns ());
   find_basic_blocks (get_insns (), max_reg_num (), 0);
-  cleanup_cfg (CLEANUP_PRE_LOOP);
+  cleanup_cfg (CLEANUP_PRE_LOOP | CLEANUP_NO_INSN_DEL);
 }
 \f
 static hashval_t

diff --git a/gcc/toplev.c b/gcc/toplev.c
index fc4f658..bb6a448 100644 (file)
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -2573,7 +2573,10 @@ rest_of_compilation (decl)
   unshare_all_rtl (current_function_decl, insns);
 
 #ifdef SETJMP_VIA_SAVE_AREA
-  /* This must be performed before virtual register instantiation.  */
+  /* This must be performed before virtual register instantiation.
+     Please be aware the everything in the compiler that can look
+     at the RTL up to this point must understand that REG_SAVE_AREA
+     is just like a use of the REG contained inside.  */
   if (current_function_calls_alloca)
     optimize_save_area_alloca (insns);
 #endif