PR debug/7055

[pf3gnuchains/gcc-fork.git] / gcc / expmed.c

diff --git a/gcc/expmed.c b/gcc/expmed.c
index 0c7e611..50eb45f 100644 (file)
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -1,7 +1,7 @@
 /* Medium-level subroutines: convert bit-field store and extract
    and shifts, multiplies and divides to rtl instructions.
    Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
+   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -532,6 +532,7 @@ store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
       int icode = optab_handler (movstrict_optab, fieldmode)->insn_code;
       rtx insn;
       rtx start = get_last_insn ();
+      rtx arg0 = op0;
 
       /* Get appropriate low part of the value being stored.  */
       if (GET_CODE (value) == CONST_INT || REG_P (value))
@@ -552,11 +553,11 @@ store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
          gcc_assert (GET_MODE (SUBREG_REG (op0)) == fieldmode
                      || GET_MODE_CLASS (fieldmode) == MODE_INT
                      || GET_MODE_CLASS (fieldmode) == MODE_PARTIAL_INT);
-         op0 = SUBREG_REG (op0);
+         arg0 = SUBREG_REG (op0);
        }
 
       insn = (GEN_FCN (icode)
-                (gen_rtx_SUBREG (fieldmode, op0,
+                (gen_rtx_SUBREG (fieldmode, arg0,
                                  (bitnum % BITS_PER_WORD) / BITS_PER_UNIT
                                  + (offset * UNITS_PER_WORD)),
                                  value));
@@ -1533,7 +1534,13 @@ extract_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
 
       if (GET_MODE (xtarget) != ext_mode)
        {
-         if (REG_P (xtarget))
+         /* Don't use LHS paradoxical subreg if explicit truncation is needed
+            between the mode of the extraction (word_mode) and the target
+            mode.  Instead, create a temporary and use convert_move to set
+            the target.  */
+         if (REG_P (xtarget)
+             && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (GET_MODE (xtarget)),
+                                       GET_MODE_BITSIZE (ext_mode)))
            {
              xtarget = gen_lowpart (ext_mode, xtarget);
              if (GET_MODE_SIZE (ext_mode)