common.opt (fvar-tracking-uninit): Document.

	* common.opt (fvar-tracking-uninit): Document.
	* toplev.c (process_options): Fix handling of flag_var_tracking_uninit.
	* config/darwin.c (darwin_override_options): Likewise.

From-SVN: r193456

gcc/ChangeLog

+2012-11-12  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* common.opt (fvar-tracking-uninit): Document.
+	* toplev.c (process_options): Fix handling of flag_var_tracking_uninit.
+	* config/darwin.c (darwin_override_options): Likewise.
+
 2012-11-12  Steven Bosscher  <steven@gcc.gnu.org>
 
 	* sched-vis.c (print_pattern): Handle NULL patterns.

gcc/common.opt

@@ -2193,6 +2193,10 @@ fvar-tracking-assignments-toggle
 Common Report Var(flag_var_tracking_assignments_toggle) Optimization
 Toggle -fvar-tracking-assignments
 
+; Positive if we should track uninitialized variables, negative if
+; we should run the var-tracking pass only to discard debug
+; annotations.  When flag_var_tracking_uninit == AUTODETECT_VALUE it
+; will be set according to flag_var_tracking.
 fvar-tracking-uninit
 Common Report Var(flag_var_tracking_uninit) Optimization
 Perform variable tracking and also tag variables that are uninitialized

gcc/config/darwin.c

@@ -3038,12 +3038,12 @@ darwin_override_options (void)
       darwin_emit_branch_islands = true;
     }
 
-  if (flag_var_tracking
+  if (flag_var_tracking_uninit == 0
       && generating_for_darwin_version >= 9
       && (flag_gtoggle ? (debug_info_level == DINFO_LEVEL_NONE)
       : (debug_info_level >= DINFO_LEVEL_NORMAL))
       && write_symbols == DWARF2_DEBUG)
-    flag_var_tracking_uninit = 1;
+    flag_var_tracking_uninit = flag_var_tracking;
 
   if (MACHO_DYNAMIC_NO_PIC_P)
     {

gcc/toplev.c

@@ -1421,12 +1421,15 @@ process_options (void)
   /* If the user specifically requested variable tracking with tagging
      uninitialized variables, we need to turn on variable tracking.
      (We already determined above that variable tracking is feasible.)  */
-  if (flag_var_tracking_uninit)
+  if (flag_var_tracking_uninit == 1)
     flag_var_tracking = 1;
 
   if (flag_var_tracking == AUTODETECT_VALUE)
     flag_var_tracking = optimize >= 1;
 
+  if (flag_var_tracking_uninit == AUTODETECT_VALUE)
+    flag_var_tracking_uninit = flag_var_tracking;
+
   if (flag_var_tracking_assignments == AUTODETECT_VALUE)
     flag_var_tracking_assignments = flag_var_tracking
       && !(flag_selective_scheduling || flag_selective_scheduling2);