Add comment provided by Jim Wilson.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@22560 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c022fc6..8351c37 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+Wed Sep 23 16:22:01 1998  Nick Clifton  <nickc@cygnus.com>
+
+       * expmed.c (extract_bit_field): Add comment from Jim Wilson. 
+
 Wed Sep 23 13:26:02 1998  Richard Henderson  <rth@cygnus.com>
 
        * alpha.c (get_aligned_mem): Revert Sep 20 change.

diff --git a/gcc/expmed.c b/gcc/expmed.c
index 730d904..734365f 100644 (file)
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -983,6 +983,10 @@ extract_bit_field (str_rtx, bitsize, bitnum, unsignedp,
       && ((bitsize >= BITS_PER_WORD && bitsize == GET_MODE_BITSIZE (mode)
           && bitpos % BITS_PER_WORD == 0)
          || (mode_for_size (bitsize, GET_MODE_CLASS (tmode), 0) != BLKmode
+             /* ??? The big endian test here is wrong.  This is correct
+                if the value is in a register, and if mode_for_size is not
+                the same mode as op0.  This causes us to get unnecessarily
+                inefficient code from the Thumb port when -mbig-endian.  */
              && (BYTES_BIG_ENDIAN
                  ? bitpos + bitsize == BITS_PER_WORD
                  : bitpos == 0))))