PR rtl-optimization/19464

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

diff --git a/gcc/expr.c b/gcc/expr.c
index 2e1320e..ea6f15a 100644 (file)
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -1,6 +1,6 @@
 /* Convert tree expression to rtl instructions, for GNU compiler.
    Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-   2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -2707,13 +2707,14 @@ read_complex_part (rtx cplx, bool imag_p)
                            true, NULL_RTX, imode, imode);
 }
 \f
-/* A subroutine of emit_move_via_alt_mode.  Yet another lowpart generator.
+/* A subroutine of emit_move_insn_1.  Yet another lowpart generator.
    NEW_MODE and OLD_MODE are the same size.  Return NULL if X cannot be
-   represented in NEW_MODE.  */
+   represented in NEW_MODE.  If FORCE is true, this will never happen, as
+   we'll force-create a SUBREG if needed.  */
 
 static rtx
 emit_move_change_mode (enum machine_mode new_mode,
-                      enum machine_mode old_mode, rtx x)
+                      enum machine_mode old_mode, rtx x, bool force)
 {
   rtx ret;
 
@@ -2731,35 +2732,22 @@ emit_move_change_mode (enum machine_mode new_mode,
     }
   else
     {
-      /* Note that we do want simplify_subreg's behaviour of validating
+      /* Note that we do want simplify_subreg's behavior of validating
         that the new mode is ok for a hard register.  If we were to use
         simplify_gen_subreg, we would create the subreg, but would
         probably run into the target not being able to implement it.  */
-      ret = simplify_subreg (new_mode, x, old_mode, 0);
+      /* Except, of course, when FORCE is true, when this is exactly what
+        we want.  Which is needed for CCmodes on some targets.  */
+      if (force)
+       ret = simplify_gen_subreg (new_mode, x, old_mode, 0);
+      else
+       ret = simplify_subreg (new_mode, x, old_mode, 0);
     }
 
   return ret;
 }
 
 /* A subroutine of emit_move_insn_1.  Generate a move from Y into X using
-   ALT_MODE instead of the operand's natural mode, MODE.  CODE is the insn
-   code for the move in ALT_MODE, and is known to be valid.  Returns the
-   instruction emitted, or NULL if X or Y cannot be represented in ALT_MODE.  */
-
-static rtx
-emit_move_via_alt_mode (enum machine_mode alt_mode, enum machine_mode mode,
-                       enum insn_code code, rtx x, rtx y)
-{
-  x = emit_move_change_mode (alt_mode, mode, x);
-  if (x == NULL_RTX)
-    return NULL_RTX;
-  y = emit_move_change_mode (alt_mode, mode, y);
-  if (y == NULL_RTX)
-    return NULL_RTX;
-  return emit_insn (GEN_FCN (code) (x, y));
-}
-
-/* A subroutine of emit_move_insn_1.  Generate a move from Y into X using
    an integer mode of the same size as MODE.  Returns the instruction
    emitted, or NULL if such a move could not be generated.  */
 
@@ -2779,7 +2767,13 @@ emit_move_via_integer (enum machine_mode mode, rtx x, rtx y)
   if (code == CODE_FOR_nothing)
     return NULL_RTX;
 
-  return emit_move_via_alt_mode (imode, mode, code, x, y);
+  x = emit_move_change_mode (imode, mode, x, false);
+  if (x == NULL_RTX)
+    return NULL_RTX;
+  y = emit_move_change_mode (imode, mode, y, false);
+  if (y == NULL_RTX)
+    return NULL_RTX;
+  return emit_insn (GEN_FCN (code) (x, y));
 }
 
 /* A subroutine of emit_move_insn_1.  X is a push_operand in MODE.
@@ -2883,7 +2877,7 @@ emit_move_complex (enum machine_mode mode, rtx x, rtx y)
   if (push_operand (x, mode))
     return emit_move_complex_push (mode, x, y);
 
-  /* For memory to memory moves, optimial behaviour can be had with the
+  /* For memory to memory moves, optimal behavior can be had with the
      existing block move logic.  */
   if (MEM_P (x) && MEM_P (y))
     {
@@ -2943,7 +2937,11 @@ emit_move_ccmode (enum machine_mode mode, rtx x, rtx y)
     {
       enum insn_code code = mov_optab->handlers[CCmode].insn_code;
       if (code != CODE_FOR_nothing)
-       return emit_move_via_alt_mode (CCmode, mode, code, x, y);
+       {
+         x = emit_move_change_mode (CCmode, mode, x, true);
+         y = emit_move_change_mode (CCmode, mode, y, true);
+         return emit_insn (GEN_FCN (code) (x, y));
+       }
     }
 
   /* Otherwise, find the MODE_INT mode of the same width.  */