(convert_modes): Can't truncate REG with gen_lowpart if

TRULY_NOOP_TRUNCATION doesn't allow it.

From-SVN: r6306

diff --git a/gcc/expr.c b/gcc/expr.c
index ed9f6eb288250e6f6b949ad34332f81fa305b8e8..f31ad2803859920fc94b4c2fd2d199b653756474 100644 (file)
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -1223,7 +1223,9 @@ convert_modes (mode, oldmode, x, unsignedp)
              || (GET_MODE_SIZE (mode) <= GET_MODE_SIZE (oldmode)
                  && ((GET_CODE (x) == MEM && ! MEM_VOLATILE_P (x)
                       && direct_load[(int) mode])
-                     || GET_CODE (x) == REG)))))
+                     || (GET_CODE (x) == REG
+                         && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
+                                                   GET_MODE_BITSIZE (GET_MODE (x)))))))))
     {
       /* ?? If we don't know OLDMODE, we have to assume here that
         X does not need sign- or zero-extension.   This may not be