Add support for reloading a frame address with an invalid base

gcc/

	* lra-constraints.c (base_to_reg): New function.
	(process_address): Use new function.

From-SVN: r211802

gcc/ChangeLog

+2014-06-18  Robert Suchanek  <robert.suchanek@imgtec.com>
+
+	* lra-constraints.c (base_to_reg): New function.       
+	(process_address): Use new function.                   
+
 2014-06-18  Tom de Vries  <tom@codesourcery.com>
 
 	* config/aarch64/aarch64-protos.h (aarch64_emit_call_insn): Declare.

gcc/lra-constraints.c

@@ -2556,6 +2556,39 @@ process_alt_operands (int only_alternative)
   return ok_p;
 }
 
+/* Make reload base reg from address AD.  */
+static rtx
+base_to_reg (struct address_info *ad)
+{
+  enum reg_class cl;
+  int code = -1;
+  rtx new_inner = NULL_RTX;
+  rtx new_reg = NULL_RTX;
+  rtx insn;
+  rtx last_insn = get_last_insn();
+
+  lra_assert (ad->base == ad->base_term && ad->disp == ad->disp_term);
+  cl = base_reg_class (ad->mode, ad->as, ad->base_outer_code,
+                       get_index_code (ad));
+  new_reg = lra_create_new_reg (GET_MODE (*ad->base_term), NULL_RTX,
+                                cl, "base");
+  new_inner = simplify_gen_binary (PLUS, GET_MODE (new_reg), new_reg,
+                                   ad->disp_term == NULL
+                                   ? gen_int_mode (0, ad->mode)
+                                   : *ad->disp_term);
+  if (!valid_address_p (ad->mode, new_inner, ad->as))
+    return NULL_RTX;
+  insn = emit_insn (gen_rtx_SET (ad->mode, new_reg, *ad->base_term));
+  code = recog_memoized (insn);
+  if (code < 0)
+    {
+      delete_insns_since (last_insn);
+      return NULL_RTX;
+    }
+
+  return new_inner;
+}
+
 /* Make reload base reg + disp from address AD.  Return the new pseudo.  */
 static rtx
 base_plus_disp_to_reg (struct address_info *ad)
@@ -2775,6 +2808,8 @@ process_address_1 (int nop, rtx *before, rtx *after)
 
      3) the address is a frame address with an invalid offset.
 
+     4) the address is a frame address with an invalid base.
+
      All these cases involve a non-autoinc address, so there is no
      point revalidating other types.  */
   if (ad.autoinc_p || valid_address_p (&ad))
@@ -2856,13 +2891,18 @@ process_address_1 (int nop, rtx *before, rtx *after)
       int regno;
       enum reg_class cl;
       rtx set, insns, last_insn;
+      /* Try to reload base into register only if the base is invalid
+         for the address but with valid offset, case (4) above.  */
+      start_sequence ();
+      new_reg = base_to_reg (&ad);
+
       /* base + disp => new base, cases (1) and (3) above.  */
       /* Another option would be to reload the displacement into an
 	 index register.  However, postreload has code to optimize
 	 address reloads that have the same base and different
 	 displacements, so reloading into an index register would
 	 not necessarily be a win.  */
-      start_sequence ();
+      if (new_reg == NULL_RTX)
         new_reg = base_plus_disp_to_reg (&ad);
       insns = get_insns ();
       last_insn = get_last_insn ();