Revert:

	2009-01-11  Adam Nemet  <anemet@caviumnetworks.com>
	* expmed.c (store_bit_field_1): Properly truncate the paradoxical
	subreg of op0 to the original op0.

	* expmed.c (store_bit_field_1): Use a temporary as the destination
	instead of a paradoxical subreg when we need to truncate the result.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@149153 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cdcc269..b1273fb 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2009-07-01  Adam Nemet  <anemet@caviumnetworks.com>
+
+       Revert:
+       2009-01-11  Adam Nemet  <anemet@caviumnetworks.com>
+       * expmed.c (store_bit_field_1): Properly truncate the paradoxical
+       subreg of op0 to the original op0.
+
+       * expmed.c (store_bit_field_1): Use a temporary as the destination
+       instead of a paradoxical subreg when we need to truncate the result.
+
 2009-07-01  DJ Delorie  <dj@redhat.com>
 
        * config/mep/mep-ivc2.cpu (cmov, cmovc, cmovh): Add intrinsic names to VLIW variants.

diff --git a/gcc/expmed.c b/gcc/expmed.c
index 3f94ac7..c540537 100644 (file)
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -685,6 +685,7 @@ store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
       rtx xop0 = op0;
       rtx last = get_last_insn ();
       rtx pat;
+      bool copy_back = false;
 
       /* Add OFFSET into OP0's address.  */
       if (MEM_P (xop0))
@@ -699,6 +700,23 @@ store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
       if (REG_P (xop0) && GET_MODE (xop0) != op_mode)
        xop0 = gen_rtx_SUBREG (op_mode, xop0, 0);
 
+      /* If the destination is a paradoxical subreg such that we need a
+        truncate to the inner mode, perform the insertion on a temporary and
+        truncate the result to the original destination.  Note that we can't
+        just truncate the paradoxical subreg as (truncate:N (subreg:W (reg:N
+        X) 0)) is (reg:N X).  */
+      if (GET_CODE (xop0) == SUBREG
+         && REG_P (SUBREG_REG (xop0))
+         && (!TRULY_NOOP_TRUNCATION
+             (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (xop0))),
+              GET_MODE_BITSIZE (op_mode))))
+       {
+         rtx tem = gen_reg_rtx (op_mode);
+         emit_move_insn (tem, xop0);
+         xop0 = tem;
+         copy_back = true;
+       }
+
       /* On big-endian machines, we count bits from the most significant.
         If the bit field insn does not, we must invert.  */
 
@@ -758,15 +776,8 @@ store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
        {
          emit_insn (pat);
 
-         /* If the mode of the insertion is wider than the mode of the
-            target register we created a paradoxical subreg for the
-            target.  Truncate the paradoxical subreg of the target to
-            itself properly.  */
-         if (!TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (GET_MODE (op0)),
-                                     GET_MODE_BITSIZE (op_mode))
-             && (REG_P (xop0)
-                 || GET_CODE (xop0) == SUBREG))
-             convert_move (op0, xop0, true);
+         if (copy_back)
+           convert_move (op0, xop0, true);
          return true;
        }
       delete_insns_since (last);