i386.c (ix86_decompose_address): Allow only subregs of DImode hard registers in index.

	* config/i386/i386.c (ix86_decompose_address): Allow only subregs
	of DImode hard registers in index.
	(ix86_legitimate_address_p): Allow subregs of base and index to span
	more than a word.  Assert that subregs of base and index satisfy
	register_no_elim_operand predicates.  Reject addresses where
	base and index have different modes.

From-SVN: r176536

gcc/ChangeLog

+2011-07-20  Uros Bizjak  <ubizjak@gmail.com>
+
+	* config/i386/i386.c (ix86_decompose_address): Allow only subregs
+	of DImode hard registers in index.
+	(ix86_legitimate_address_p): Allow subregs of base and index to span
+	more than a word.  Assert that subregs of base and index satisfy
+	register_no_elim_operand predicates.  Reject addresses where
+	base and index have different modes.
+
 2011-07-20  Robert Millan  <rmh@gnu.org>
 
 	* config.gcc (mips*-*-linux*): Remove redundant tm_file entry.
@@ -13,12 +22,11 @@
 	memory address space to the type's address space.
 
 2011-07-20  Georg-Johann Lay  <avr@gjlay.de>
-	
+
 	PR target/36467
 	PR target/49687
-	* config/avr/avr.md (mulhi3): Use register_or_s9_operand for
-	operand2 and expand appropriately if there is a CONST_INT in
-	operand2.
+	* config/avr/avr.md (mulhi3): Use register_or_s9_operand for operand2
+	and expand appropriately if there is a CONST_INT in operand2.
 	(usmulqihi3): New insn.
 	(*sumulqihi3): New insn.
 	(*osmulqihi3): New insn.

gcc/config/i386/i386.c

@@ -11197,6 +11197,16 @@ ix86_decompose_address (rtx addr, struct ix86_address *out)
   else
     disp = addr;			/* displacement */
 
+  if (index)
+    {
+      if (REG_P (index))
+	;
+      /* Allow only subregs of DImode hard regs.  */
+      else if (GET_CODE (index) == SUBREG
+	       && !register_no_elim_operand (SUBREG_REG (index), DImode))
+	return 0;
+    }
+
   /* Extract the integral value of scale.  */
   if (scale_rtx)
     {
@@ -11630,23 +11640,18 @@ ix86_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
   disp = parts.disp;
   scale = parts.scale;
 
-  /* Validate base register.
-
-     Don't allow SUBREG's that span more than a word here.  It can lead to spill
-     failures when the base is one word out of a two word structure, which is
-     represented internally as a DImode int.  */
-
+  /* Validate base register.  */
   if (base)
     {
       rtx reg;
 
       if (REG_P (base))
   	reg = base;
-      else if (GET_CODE (base) == SUBREG
-	       && REG_P (SUBREG_REG (base))
-	       && GET_MODE_SIZE (GET_MODE (SUBREG_REG (base)))
-		  <= UNITS_PER_WORD)
-  	reg = SUBREG_REG (base);
+      else if (GET_CODE (base) == SUBREG && REG_P (SUBREG_REG (base)))
+	{
+	  reg = SUBREG_REG (base);
+	  gcc_assert (register_no_elim_operand (reg, DImode));
+	}
       else
 	/* Base is not a register.  */
 	return false;
@@ -11660,21 +11665,18 @@ ix86_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
 	return false;
     }
 
-  /* Validate index register.
-
-     Don't allow SUBREG's that span more than a word here -- same as above.  */
-
+  /* Validate index register.  */
   if (index)
     {
       rtx reg;
 
       if (REG_P (index))
   	reg = index;
-      else if (GET_CODE (index) == SUBREG
-	       && REG_P (SUBREG_REG (index))
-	       && GET_MODE_SIZE (GET_MODE (SUBREG_REG (index)))
-		  <= UNITS_PER_WORD)
-  	reg = SUBREG_REG (index);
+      else if (GET_CODE (index) == SUBREG && REG_P (SUBREG_REG (index)))
+	{
+	  reg = SUBREG_REG (index);
+	  gcc_assert (register_no_elim_operand (reg, DImode));
+	}
       else
 	/* Index is not a register.  */
 	return false;
@@ -11688,6 +11690,11 @@ ix86_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
 	return false;
     }
 
+  /* Index and base should have the same mode.  */
+  if (base && index
+      && GET_MODE (base) != GET_MODE (index))
+    return false;
+
   /* Validate scale factor.  */
   if (scale != 1)
     {