postreload.c (reload_combine): Check that REGY doesn't die in an insn of the form...

* postreload.c (reload_combine): Check that REGY doesn't die in an
insn of the form (set (regx) (plus (regx) (regy))), ie REGX != REGY.

From-SVN: r73148

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 24954ff..b692768 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2003-10-31  Richard Earnshaw  <rearnsha@arm.com>
+
+       * postreload.c (reload_combine): Check that REGY doesn't die in an
+       insn of the form (set (regx) (plus (regx) (regy))), ie REGX != REGY.
+
 2003-10-31  Josef Zlomek  <zlomekj@suse.cz>
 
        PR/10239

diff --git a/gcc/postreload.c b/gcc/postreload.c
index f5a987a..362b50e 100644 (file)
--- a/gcc/postreload.c
+++ b/gcc/postreload.c
@@ -718,7 +718,9 @@ reload_combine (void)
         ... (MEM (PLUS (REGZ) (REGY)))... .
 
         First, check that we have (set (REGX) (PLUS (REGX) (REGY)))
-        and that we know all uses of REGX before it dies.  */
+        and that we know all uses of REGX before it dies.  
+        Also, explicitly check that REGX != REGY; our life information
+        does not yet show whether REGY changes in this insn.  */
       set = single_set (insn);
       if (set != NULL_RTX
          && GET_CODE (SET_DEST (set)) == REG
@@ -728,6 +730,7 @@ reload_combine (void)
          && GET_CODE (SET_SRC (set)) == PLUS
          && GET_CODE (XEXP (SET_SRC (set), 1)) == REG
          && rtx_equal_p (XEXP (SET_SRC (set), 0), SET_DEST (set))
+         && !rtx_equal_p (XEXP (SET_SRC (set), 1), SET_DEST (set))
          && last_label_ruid < reg_state[REGNO (SET_DEST (set))].use_ruid)
        {
          rtx reg = SET_DEST (set);