(subst, case SUBREG): Don't make a new REG for stack, frame, or arg

pointer.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@2381 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/combine.c b/gcc/combine.c
index 0442860..cc7f8f8 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -2900,10 +2900,16 @@ subst (x, from, to, in_dest, unique_copy)
 
       /* SUBREG of a hard register => just change the register number
         and/or mode.  If the hard register is not valid in that mode,
-        suppress this combination.  */
+        suppress this combination.  If the hard register is the stack,
+        frame, or argument pointer, leave this as a SUBREG.  */
 
       if (GET_CODE (SUBREG_REG (x)) == REG
-         && REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER)
+         && REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER
+         && REGNO (SUBREG_REG (x)) != FRAME_POINTER_REGNUM
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+         && REGNO (SUBREG_REG (x)) != ARG_POINTER_REGNUM
+#endif
+         && REGNO (SUBREG_REG (x)) != STACK_POINTER_REGNUM)
        {
          if (HARD_REGNO_MODE_OK (REGNO (SUBREG_REG (x)) + SUBREG_WORD (x),
                                  mode))