fe.h (Suppress_Checks): Declare.

	* fe.h (Suppress_Checks): Declare.
	* gcc-interface/misc.c (gnat_init_gcc_eh): Set -fnon-call-exceptions
	only if checks are not suppressed and -faggressive-loop-optimizations
	only if they are.
	* gcc-interface/trans.c (struct loop_info_d): Remove has_checks and
	warned_aggressive_loop_optimizations fields.
	(gigi): Do not clear warn_aggressive_loop_optimizations here.
	(Raise_Error_to_gnu): Do not set has_checks.
	(gnat_to_gnu) <N_Indexed_Component>: Remove support for aggressive
	loop optimizations.

From-SVN: r265921

4 files changed, 26 insertions, 54 deletions

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index a1b3c66..ee8ba62 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,5 +1,18 @@
 2018-11-08  Eric Botcazou  <ebotcazou@adacore.com>
 
+	* fe.h (Suppress_Checks): Declare.
+	* gcc-interface/misc.c (gnat_init_gcc_eh): Set -fnon-call-exceptions
+	only if checks are not suppressed and -faggressive-loop-optimizations
+	only if they are.
+	* gcc-interface/trans.c (struct loop_info_d): Remove has_checks and
+	warned_aggressive_loop_optimizations fields.
+	(gigi): Do not clear warn_aggressive_loop_optimizations here.
+	(Raise_Error_to_gnu): Do not set has_checks.
+	(gnat_to_gnu) <N_Indexed_Component>: Remove support for aggressive
+	loop optimizations.
+
+2018-11-08  Eric Botcazou  <ebotcazou@adacore.com>
+
 	* gcc-interface/decl.c (components_to_record): Remove obsolete kludge.
 	* gcc-interface/utils.c (make_packable_type): Set TYPE_PACKED on the
 	new type but do not take into account the setting on the old type for
diff --git a/gcc/ada/fe.h b/gcc/ada/fe.h
index b0ccbdc..d4c4265 100644
--- a/gcc/ada/fe.h
+++ b/gcc/ada/fe.h
@@ -193,6 +193,7 @@ extern Boolean In_Same_Source_Unit              (Node_Id, Node_Id);
 #define GNAT_Mode                      opt__gnat_mode
 #define List_Representation_Info       opt__list_representation_info
 #define No_Strict_Aliasing_CP          opt__no_strict_aliasing
+#define Suppress_Checks                opt__suppress_checks
 
 typedef enum {
   Front_End_SJLJ, Back_End_ZCX, Back_End_SJLJ
@@ -207,6 +208,7 @@ extern Boolean Generate_SCO_Instance_Table;
 extern Boolean GNAT_Mode;
 extern Int List_Representation_Info;
 extern Boolean No_Strict_Aliasing_CP;
+extern Boolean Suppress_Checks;
 
 #define ZCX_Exceptions            opt__zcx_exceptions
 #define SJLJ_Exceptions           opt__sjlj_exceptions
diff --git a/gcc/ada/gcc-interface/misc.c b/gcc/ada/gcc-interface/misc.c
index 98ec277..eadbd36 100644
--- a/gcc/ada/gcc-interface/misc.c
+++ b/gcc/ada/gcc-interface/misc.c
@@ -392,7 +392,7 @@ gnat_init_gcc_eh (void)
   using_eh_for_cleanups ();
 
   /* Turn on -fexceptions, -fnon-call-exceptions and -fdelete-dead-exceptions.
-     The first one triggers the generation of the necessary exception tables.
+     The first one activates the support for exceptions in the compiler.
      The second one is useful for two reasons: 1/ we map some asynchronous
      signals like SEGV to exceptions, so we need to ensure that the insns
      which can lead to such signals are correctly attached to the exception
@@ -402,10 +402,18 @@ gnat_init_gcc_eh (void)
      for such calls to actually raise in Ada.
      The third one is an optimization that makes it possible to delete dead
      instructions that may throw exceptions, most notably loads and stores,
-     as permitted in Ada.  */
+     as permitted in Ada.
+     Turn off -faggressive-loop-optimizations because it may optimize away
+     out-of-bound array accesses that we want to be able to catch.
+     If checks are disabled, we use the same settings as the C++ compiler.  */
   flag_exceptions = 1;
-  flag_non_call_exceptions = 1;
   flag_delete_dead_exceptions = 1;
+  if (!Suppress_Checks)
+    {
+      flag_non_call_exceptions = 1;
+      flag_aggressive_loop_optimizations = 0;
+      warn_aggressive_loop_optimizations = 0;
+    }
 
   init_eh ();
 }
diff --git a/gcc/ada/gcc-interface/trans.c b/gcc/ada/gcc-interface/trans.c
index ce2d43f..2cd7102 100644
--- a/gcc/ada/gcc-interface/trans.c
+++ b/gcc/ada/gcc-interface/trans.c
@@ -198,8 +198,6 @@ struct GTY(()) loop_info_d {
   tree high_bound;
   vec<range_check_info, va_gc> *checks;
   bool artificial;
-  bool has_checks;
-  bool warned_aggressive_loop_optimizations;
 };
 
 typedef struct loop_info_d *loop_info;
@@ -679,10 +677,6 @@ gigi (Node_Id gnat_root,
   /* Now translate the compilation unit proper.  */
   Compilation_Unit_to_gnu (gnat_root);
 
-  /* Disable -Waggressive-loop-optimizations since we implement our own
-     version of the warning.  */
-  warn_aggressive_loop_optimizations = 0;
-
   /* Then process the N_Validate_Unchecked_Conversion nodes.  We do this at
      the very end to avoid having to second-guess the front-end when we run
      into dummy nodes during the regular processing.  */
@@ -5720,7 +5714,6 @@ Raise_Error_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p)
 	      rci->inserted_cond
 		= build1 (SAVE_EXPR, boolean_type_node, boolean_true_node);
 	      vec_safe_push (loop->checks, rci);
-	      loop->has_checks = true;
 	      gnu_cond = build_noreturn_cond (gnat_to_gnu (gnat_cond));
 	      if (flag_unswitch_loops)
 		gnu_cond = build_binary_op (TRUTH_ANDIF_EXPR,
@@ -5733,14 +5726,6 @@ Raise_Error_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p)
 					    gnu_cond,
 					    rci->inserted_cond);
 	    }
-
-	  /* Or else, if aggressive loop optimizations are enabled, we just
-	     record that there are checks applied to iteration variables.  */
-	  else if (optimize
-		   && flag_aggressive_loop_optimizations
-		   && inside_loop_p ()
-		   && (loop = find_loop_for (gnu_index)))
-	    loop->has_checks = true;
 	}
       break;
 
@@ -6359,45 +6344,9 @@ gnat_to_gnu (Node_Id gnat_node)
 	    gcc_assert (TREE_CODE (gnu_type) == ARRAY_TYPE);
 	    gnat_temp = gnat_expr_array[i];
 	    gnu_expr = maybe_character_value (gnat_to_gnu (gnat_temp));
-	    struct loop_info_d *loop;
 
 	    gnu_result
 	      = build_binary_op (ARRAY_REF, NULL_TREE, gnu_result, gnu_expr);
-
-	    /* Array accesses are bound-checked so they cannot trap, but this
-	       is valid only if they are not hoisted ahead of the check.  We
-	       need to mark them as no-trap to get decent loop optimizations
-	       in the presence of -fnon-call-exceptions, so we do it when we
-	       know that the original expression had no side-effects.  */
-	    if (TREE_CODE (gnu_result) == ARRAY_REF
-		&& !(Nkind (gnat_temp) == N_Identifier
-		     && Ekind (Entity (gnat_temp)) == E_Constant))
-	      TREE_THIS_NOTRAP (gnu_result) = 1;
-
-	    /* If aggressive loop optimizations are enabled, we warn for loops
-	       overrunning a simple array of size 1 not at the end of a record.
-	       This is aimed to catch misuses of the trailing array idiom.  */
-	    if (optimize
-		&& flag_aggressive_loop_optimizations
-		&& inside_loop_p ()
-		&& TREE_CODE (TREE_TYPE (gnu_type)) != ARRAY_TYPE
-		&& TREE_CODE (gnu_array_object) != ARRAY_REF
-		&& tree_int_cst_equal (TYPE_MIN_VALUE (TYPE_DOMAIN (gnu_type)),
-				       TYPE_MAX_VALUE (TYPE_DOMAIN (gnu_type)))
-		&& !array_at_struct_end_p (gnu_result)
-		&& (loop = find_loop_for (gnu_expr))
-		&& !loop->artificial
-		&& !loop->has_checks
-		&& tree_int_cst_equal (TYPE_MIN_VALUE (TYPE_DOMAIN (gnu_type)),
-				       loop->low_bound)
-		&& can_be_lower_p (loop->low_bound, loop->high_bound)
-		&& !loop->warned_aggressive_loop_optimizations
-		&& warning (OPT_Waggressive_loop_optimizations,
-			    "out-of-bounds access may be optimized away"))
-	      {
-		inform (EXPR_LOCATION (loop->stmt), "containing loop");
-		loop->warned_aggressive_loop_optimizations = true;
-	      }
 	  }
 
 	gnu_result_type = get_unpadded_type (Etype (gnat_node));