* rtlanal.c (subreg_regno_offset): Return correct offset for

	big endian paradoxical subregs.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@55650 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 10 insertions, 0 deletions

diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index de7efae2d5f..c1fdb7604ae 100644
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -3117,6 +3117,16 @@ subreg_regno_offset (xregno, xmode, offset, ymode)
 
   nregs_xmode = HARD_REGNO_NREGS (xregno, xmode);
   nregs_ymode = HARD_REGNO_NREGS (xregno, ymode);
+
+  /* If this is a big endian paradoxical subreg, which uses more actual
+     hard registers than the original register, we must return a negative
+     offset so that we find the proper highpart of the register.  */
+  if (offset == 0
+      && nregs_ymode > nregs_xmode
+      && (GET_MODE_SIZE (ymode) > UNITS_PER_WORD
+	  ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
+    return nregs_xmode - nregs_ymode;
+
   if (offset == 0 || nregs_xmode == nregs_ymode)
     return 0;