arm.c (thumb1_reorg): Search for flag setting insn before branch in same basic block.

	* config/arm/arm.c (thumb1_reorg): Search for flag setting insn
	before branch in same basic block.  Check both src and dest of
	the move insn.

From-SVN: r202678

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d2c79a1..3524ca8 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2013-09-18  Bin Cheng  <bin.cheng@arm.com>
+
+       * config/arm/arm.c (thumb1_reorg): Search for flag setting insn
+       before branch in same basic block.  Check both src and dest of
+       the move insn.
+
 2013-09-17  Nick Clifton  <nickc@redhat.com>
 
        * config/rl78/rl78-real.md (bf): New pattern.

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index f9027dd..176f719 100644 (file)
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -14265,9 +14265,10 @@ thumb1_reorg (void)
 
   FOR_EACH_BB (bb)
     {
-      rtx set, dest, src;
-      rtx pat, op0;
+      rtx dest, src;
+      rtx pat, op0, set = NULL;
       rtx prev, insn = BB_END (bb);
+      bool insn_clobbered = false;
 
       while (insn != BB_HEAD (bb) && DEBUG_INSN_P (insn))
        insn = PREV_INSN (insn);
@@ -14276,13 +14277,29 @@ thumb1_reorg (void)
       if (INSN_CODE (insn) != CODE_FOR_cbranchsi4_insn)
        continue;
 
-      /* Find the first non-note insn before INSN in basic block BB.  */
+      /* Get the register with which we are comparing.  */
+      pat = PATTERN (insn);
+      op0 = XEXP (XEXP (SET_SRC (pat), 0), 0);
+
+      /* Find the first flag setting insn before INSN in basic block BB.  */
       gcc_assert (insn != BB_HEAD (bb));
-      prev = PREV_INSN (insn);
-      while (prev != BB_HEAD (bb) && (NOTE_P (prev) || DEBUG_INSN_P (prev)))
-       prev = PREV_INSN (prev);
+      for (prev = PREV_INSN (insn);
+          (!insn_clobbered
+           && prev != BB_HEAD (bb)
+           && (NOTE_P (prev)
+               || DEBUG_INSN_P (prev)
+               || ((set = single_set (prev)) != NULL
+                   && get_attr_conds (prev) == CONDS_NOCOND)));
+          prev = PREV_INSN (prev))
+       {
+         if (reg_set_p (op0, prev))
+           insn_clobbered = true;
+       }
+
+      /* Skip if op0 is clobbered by insn other than prev. */
+      if (insn_clobbered)
+       continue;
 
-      set = single_set (prev);
       if (!set)
        continue;
 
@@ -14292,12 +14309,9 @@ thumb1_reorg (void)
          || !low_register_operand (src, SImode))
        continue;
 
-      pat = PATTERN (insn);
-      op0 = XEXP (XEXP (SET_SRC (pat), 0), 0);
       /* Rewrite move into subtract of 0 if its operand is compared with ZERO
-        in INSN. Don't need to check dest since cprop_hardreg pass propagates
-        src into INSN.  */
-      if (REGNO (op0) == REGNO (src))
+        in INSN.  Both src and dest of the move insn are checked.  */
+      if (REGNO (op0) == REGNO (src) || REGNO (op0) == REGNO (dest))
        {
          dest = copy_rtx (dest);
          src = copy_rtx (src);