arm.c (thumb1_reorg): Check that the comparison is against the constant 0.

2016-01-18  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    * config/arm/arm.c (thumb1_reorg): Check that the comparison is
    against the constant 0.

From-SVN: r232493

gcc/ChangeLog

+2016-01-18  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
+	* config/arm/arm.c (thumb1_reorg): Check that the comparison is
+	against the constant 0.
+
 2016-01-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
 	PR tree-optimization/68799

gcc/config/arm/arm.c

@@ -17206,7 +17206,7 @@ thumb1_reorg (void)
   FOR_EACH_BB_FN (bb, cfun)
     {
       rtx dest, src;
-      rtx pat, op0, set = NULL;
+      rtx cmp, op0, op1, set = NULL;
       rtx_insn *prev, *insn = BB_END (bb);
       bool insn_clobbered = false;
 
@@ -17219,8 +17219,13 @@ thumb1_reorg (void)
 	continue;
 
       /* Get the register with which we are comparing.  */
-      pat = PATTERN (insn);
-      op0 = XEXP (XEXP (SET_SRC (pat), 0), 0);
+      cmp = XEXP (SET_SRC (PATTERN (insn)), 0);
+      op0 = XEXP (cmp, 0);
+      op1 = XEXP (cmp, 1);
+
+      /* Check that comparison is against ZERO.  */
+      if (!CONST_INT_P (op1) || INTVAL (op1) != 0)
+	continue;
 
       /* Find the first flag setting insn before INSN in basic block BB.  */
       gcc_assert (insn != BB_HEAD (bb));
@@ -17260,7 +17265,7 @@ thumb1_reorg (void)
 	  PATTERN (prev) = gen_rtx_SET (dest, src);
 	  INSN_CODE (prev) = -1;
 	  /* Set test register in INSN to dest.  */
-	  XEXP (XEXP (SET_SRC (pat), 0), 0) = copy_rtx (dest);
+	  XEXP (cmp, 0) = copy_rtx (dest);
 	  INSN_CODE (insn) = -1;
 	}
     }