* combine.c (make_extraction): Correct offset computation.

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

diff --git a/gcc/combine.c b/gcc/combine.c
index 3be34e4..ff10663 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -6512,11 +6512,12 @@ make_extraction (enum machine_mode mode, rtx inner, HOST_WIDE_INT pos,
        offset -= GET_MODE_SIZE (is_mode) - GET_MODE_SIZE (inner_mode);
 
       /* If this is a constant position, we can move to the desired byte.
-        Be careful not to go beyond the original object. */
+        Be careful not to go beyond the original object and maintain the
+        natural alignment of the memory.  */ 
       if (pos_rtx == 0)
        {
          enum machine_mode bfmode = smallest_mode_for_size (len, MODE_INT);
-         offset += pos / GET_MODE_BITSIZE (bfmode);
+         offset += (pos / GET_MODE_BITSIZE (bfmode)) * GET_MODE_SIZE (bfmode);
          pos %= GET_MODE_BITSIZE (bfmode);
        }