reload1.c (verify_initial_offsets): New function.

        * reload1.c (verify_initial_offsets): New function.
        (reload): Call it after reload_as_needed.  Also verify that the frame
        size stays constant during reload_as_needed.
        * i386.h (CONST_DOUBLE_OK_FOR_LETTER_P): Undo Jul 26 change.

From-SVN: r23378

gcc/ChangeLog

@@ -12,6 +12,11 @@ Wed Oct 28 00:10:35 1998  Jeffrey A Law  (law@cygnus.com)
 
 Tue Oct 27 23:32:34 1998  Bernd Schmidt <crux@pool.informatik.rwth-aachen.de>
 
+	* reload1.c (verify_initial_offsets): New function.
+	(reload): Call it after reload_as_needed.  Also verify that the frame
+	size stays constant during reload_as_needed.
+	* i386.h (CONST_DOUBLE_OK_FOR_LETTER_P): Undo Jul 26 change.
+
 	* reload.h (struct insn_chain): Add need_operand_change element.
 	* reload1.c (new_insn_chain): Clear it.
 	(calculate_needs_all_insns): Set it; don't overload need_reload.

gcc/config/i386/i386.h

@@ -891,19 +891,10 @@ enum reg_class
 /* Similar, but for floating constants, and defining letters G and H.
    Here VALUE is the CONST_DOUBLE rtx itself.  We allow constants even if
    TARGET_387 isn't set, because the stack register converter may need to
-   load 0.0 into the function value register.
-
-   We disallow these constants when -fomit-frame-pointer and compiling
-   PIC code since reload might need to force the constant to memory.
-   Forcing the constant to memory changes the elimination offsets after
-   the point where they must stay constant.
-
-   However, we must allow them after reload as completed as reg-stack.c
-   will create insns which use these constants.  */
+   load 0.0 into the function value register.  */
 
 #define CONST_DOUBLE_OK_FOR_LETTER_P(VALUE, C)  \
-  (((reload_completed || !flag_pic || !flag_omit_frame_pointer) && (C) == 'G') \
-   ? standard_80387_constant_p (VALUE) : 0)
+  ((C) == 'G' ? standard_80387_constant_p (VALUE) : 0)
 
 /* Place additional restrictions on the register class to use when it
    is necessary to be able to hold a value of mode MODE in a reload

gcc/reload1.c

@@ -377,6 +377,7 @@ static int eliminate_regs_in_insn	PROTO((rtx, int));
 static void update_eliminable_offsets	PROTO((void));
 static void mark_not_eliminable		PROTO((rtx, rtx));
 static void set_initial_elim_offsets	PROTO((void));
+static void verify_initial_elim_offsets	PROTO((void));
 static void init_elim_table		PROTO((void));
 static void update_eliminables		PROTO((HARD_REG_SET *));
 static void spill_hard_reg		PROTO((int, FILE *, int));
@@ -970,7 +971,17 @@ reload (first, global, dumpfile)
 
   if (insns_need_reload != 0 || something_needs_elimination
       || something_needs_operands_changed)
-    reload_as_needed (global);
+    {
+      int old_frame_size = get_frame_size ();
+
+      reload_as_needed (global);
+
+      if (old_frame_size != get_frame_size ())
+	abort ();
+
+      if (num_eliminable)
+	verify_initial_elim_offsets ();
+    }
 
   /* If we were able to eliminate the frame pointer, show that it is no
      longer live at the start of any basic block.  If it ls live by
@@ -3422,6 +3433,31 @@ mark_not_eliminable (dest, x)
       }
 }
 
+/* Verify that the initial elimination offsets did not change since the
+   last call to set_initial_elim_offsets.  This is used to catch cases
+   where something illegal happened during reload_as_needed that could
+   cause incorrect code to be generated if we did not check for it.  */
+static void
+verify_initial_elim_offsets ()
+{
+  int t;
+
+#ifdef ELIMINABLE_REGS
+  struct elim_table *ep;
+
+  for (ep = reg_eliminate; ep < &reg_eliminate[NUM_ELIMINABLE_REGS]; ep++)
+    {
+      INITIAL_ELIMINATION_OFFSET (ep->from, ep->to, t);
+      if (t != ep->initial_offset)
+	abort ();
+    }
+#else
+  INITIAL_FRAME_POINTER_OFFSET (t);
+  if (t != reg_eliminate[0].initial_offset)
+    abort ();
+#endif  
+}
+
 /* Reset all offsets on eliminable registers to their initial values.  */
 static void
 set_initial_elim_offsets ()