re PR tree-optimization/50873 (The fix to PR50730 causes gcc.c-torture/unsorted/dilayout.c to ICE)

gcc/
	PR middle-end/50873
	* optabs.c (maybe_legitimize_operand_same_code): Use copy_to_mode_reg
	instead of force_reg.  Do nothing if the address is already a
	non-virtual pseudo register.

From-SVN: r182244

gcc/ChangeLog

+2011-12-12  Richard Sandiford  <richard.sandiford@linaro.org>
+
+	PR middle-end/50873
+	* optabs.c (maybe_legitimize_operand_same_code): Use copy_to_mode_reg
+	instead of force_reg.  Do nothing if the address is already a
+	non-virtual pseudo register.
+
 2011-12-12  Torvald Riegel  <triegel@redhat.com>
 
 	* gimplify.c (voidify_wrapper_expr): Add default handling for

gcc/optabs.c

@@ -8242,18 +8242,24 @@ maybe_legitimize_operand_same_code (enum insn_code icode, unsigned int opno,
     return true;
 
   /* If the operand is a memory whose address has no side effects,
-     try forcing the address into a register.  The check for side
-     effects is important because force_reg cannot handle things
-     like auto-modified addresses.  */
-  if (insn_data[(int) icode].operand[opno].allows_mem
-      && MEM_P (op->value)
-      && !side_effects_p (XEXP (op->value, 0)))
+     try forcing the address into a non-virtual pseudo register.
+     The check for side effects is important because copy_to_mode_reg
+     cannot handle things like auto-modified addresses.  */
+  if (insn_data[(int) icode].operand[opno].allows_mem && MEM_P (op->value))
     {
-      rtx addr, mem, last;
+      rtx addr, mem;
+
+      mem = op->value;
+      addr = XEXP (mem, 0);
+      if (!(REG_P (addr) && REGNO (addr) > LAST_VIRTUAL_REGISTER)
+	  && !side_effects_p (addr))
+	{
+	  rtx last;
+	  enum machine_mode mode;
 
 	  last = get_last_insn ();
-      addr = force_reg (Pmode, XEXP (op->value, 0));
-      mem = replace_equiv_address (op->value, addr);
+	  mode = targetm.addr_space.address_mode (MEM_ADDR_SPACE (mem));
+	  mem = replace_equiv_address (mem, copy_to_mode_reg (mode, addr));
 	  if (insn_operand_matches (icode, opno, mem))
 	    {
 	      op->value = mem;
@@ -8261,6 +8267,7 @@ maybe_legitimize_operand_same_code (enum insn_code icode, unsigned int opno,
 	    }
 	  delete_insns_since (last);
 	}
+    }
 
   return false;
 }