simplify_rtx.c (simplify_subreg): Keep subregs on return values...

	* simplify_rtx.c (simplify_subreg): Keep subregs on return values,
	check CLASS_CANNOT_CHANGE_MODE before avoiding subreg on hard reg,
	in case register wasn't OK previously, accept it now; allow
	subregs of frame pointer if reload completed and frame pointer
	is not needed.

	* combine.c (sombine_simplify_rtx): Fix comment;
	use subreg_lowpart_offset instead of subreg_lowpart_p
	(gen_lowpart_for_combine): Use subreg_lowpart_offset.
	* rtl.h (subreg_lowpart_parts_p): Kill.
	(subreg_lowpart_offset, subreg_highpart_offset): Declare.
	* simplify-rtx.c (simplify_subreg): Use subreg_lowpart_offset.
	* emit-rtl.c (gen_lowpart_SUBREG): Use subreg_lowpart_offset;
	(gen_lowpart_common): Likewise.
	(subreg_lowpart_p): Likewise.
	(subreg_lowpart_parts_p): Kill.
	(subreg_lowpart_offset, subreg_highpart_offset): New function.

	* emit-rtl.c (gen_lowpart_common): Use simplify_gen_subreg
	to simplify SUBREG and REG.
	(gen_highpart): Use simplify_gen_subreg for all simplifications.

	* emit-rtl.c (gen_realpart, gen_imagpart): Do not handle
	CONCAT specially.

	* rtlanal.c (replace_regs):  Use simplify_gen_subreg

From-SVN: r42850

1 files changed, 3 insertions, 34 deletions

diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index af0f81f..0f0f6cd 100644
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -2258,40 +2258,9 @@ replace_regs (x, reg_map, nregs, replace_dest)
 	  && GET_CODE (reg_map[REGNO (SUBREG_REG (x))]) == SUBREG)
 	{
 	  rtx map_val = reg_map[REGNO (SUBREG_REG (x))];
-	  rtx map_inner = SUBREG_REG (map_val);
-
-	  if (GET_MODE (x) == GET_MODE (map_inner))
-	    return map_inner;
-	  else
-	    {
-	      int final_offset = SUBREG_BYTE (x) + SUBREG_BYTE (map_val);
-
-	      /* When working with REG SUBREGs the rule is that the byte
-		 offset must be a multiple of the SUBREG's mode.  */
-	      final_offset = (final_offset / GET_MODE_SIZE (GET_MODE (x)));
-	      final_offset = (final_offset * GET_MODE_SIZE (GET_MODE (x)));
-
-	      /* We cannot call gen_rtx here since we may be linked with
-		 genattrtab.c.  */
-	      /* Let's try clobbering the incoming SUBREG and see
-		 if this is really safe.  */
-	      SUBREG_REG (x) = map_inner;
-	      SUBREG_BYTE (x) = final_offset;
-	      return x;
-#if 0
-	      rtx new = rtx_alloc (SUBREG);
-	      int final_offset = SUBREG_BYTE (x) + SUBREG_BYTE (map_val);
-
-	      /* When working with REG SUBREGs the rule is that the byte
-		 offset must be a multiple of the SUBREG's mode.  */
-	      final_offset = (final_offset / GET_MODE_SIZE (GET_MODE (x)));
-	      final_offset = (final_offset * GET_MODE_SIZE (GET_MODE (x)));
-
-	      PUT_MODE (new, GET_MODE (x));
-	      SUBREG_REG (new) = map_inner;
-	      SUBREG_BYTE (new) = final_offset;
-#endif
-	    }
+	  return simplify_gen_subreg (GET_MODE (x), map_val,
+				      GET_MODE (SUBREG_REG (x)), 
+				      SUBREG_BYTE (x));
 	}
       break;