PR optimization/8967

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

diff --git a/gcc/flow.c b/gcc/flow.c
index 4bc33e2..66c04ee 100644 (file)
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -1974,13 +1974,6 @@ init_propagate_block_info (basic_block bb, regset live, regset local_set,
            rtx mem = SET_DEST (set);
            rtx canon_mem = canon_rtx (mem);
 
-           /* This optimization is performed by faking a store to the
-              memory at the end of the block.  This doesn't work for
-              unchanging memories because multiple stores to unchanging
-              memory is illegal and alias analysis doesn't consider it.  */
-           if (RTX_UNCHANGING_P (canon_mem))
-             continue;
-
            if (XEXP (canon_mem, 0) == frame_pointer_rtx
                || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
                    && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
@@ -2152,7 +2145,7 @@ insn_dead_p (struct propagate_block_info *pbi, rtx x, int call_ok,
             rtx_equal_p does not check the alias set or flags, we also
             must have the potential for them to conflict (anti_dependence).  */
          for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
-           if (anti_dependence (r, XEXP (temp, 0)))
+           if (unchanging_anti_dependence (r, XEXP (temp, 0)))
              {
                rtx mem = XEXP (temp, 0);
 
@@ -3730,7 +3723,7 @@ mark_used_regs (struct propagate_block_info *pbi, rtx x, rtx cond, rtx insn)
              while (temp)
                {
                  next = XEXP (temp, 1);
-                 if (anti_dependence (XEXP (temp, 0), x))
+                 if (unchanging_anti_dependence (XEXP (temp, 0), x))
                    {
                      /* Splice temp out of the list.  */
                      if (prev)