msp430-gcc-4.5.3-20110706-sf3431602.patch

From d30b1b20e23f099959ce763e7a0e8bf382db7fdd Mon Sep 17 00:00:00 2001
From: "Peter A. Bigot" <pabigot@users.sourceforge.net>
Date: Thu, 3 Nov 2011 11:10:21 -0500
Subject: [PATCH] SF 3431602 Incorrect comparison to 32-bit literal

Account for unsigned overflow when converting condition bounds to match
MSP430 jump instructions.
---
 gcc/config/msp430/msp430-cbranch.c |   24 +++++++++++++++++-------
 1 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/gcc/config/msp430/msp430-cbranch.c b/gcc/config/msp430/msp430-cbranch.c
index f2bcbb8..6ce983e 100644
--- a/gcc/config/msp430/msp430-cbranch.c
+++ b/gcc/config/msp430/msp430-cbranch.c
@@ -321,27 +321,35 @@ msp430_cbranch (rtx insn, rtx operands[])
     }
   gcc_assert (mode == QImode || mode == HImode);
 
-  /* here check wiered conditions */
+  /* Correct for constant comparisons not directly supported by MSP430 */
   if (ops[1] && GET_CODE (ops[1]) == CONST_INT
       && (code == GT || code == LE || code == GTU || code == LEU))
     {
-      int x = INTVAL (ops[1]);
+      int new_bound = 1 + INTVAL (ops[1]);
+
+      if (0 == trunc_int_for_mode (new_bound, mode)
+	  && (code == GTU || code == LEU))
+	{
+	  if (code == LEU)
+	    if (distance > 500 || distance < -500)
+	      output_asm_insn ("jmp\t+4\n\tbr\t#%0", operands);
+	    else
+	      output_asm_insn ("jmp\t%0", operands);
+	  return "";
+	}
+      ops[1] = GEN_INT (new_bound);
       switch (code)
 	{
 	case GT:
-	  ops[1] = GEN_INT (x + 1);
 	  code = GE;
 	  break;
 	case LE:
-	  ops[1] = GEN_INT (x + 1);
 	  code = LT;
 	  break;
 	case GTU:
-	  ops[1] = GEN_INT (x + 1);
 	  code = GEU;
 	  break;
 	case LEU:
-	  ops[1] = GEN_INT (x + 1);
 	  code = LTU;
 	  break;
 	default:
@@ -351,7 +359,9 @@ msp430_cbranch (rtx insn, rtx operands[])
   else if (ops[1] && CONSTANT_P (ops[1]) && GET_MODE (ops[1]) == HImode
 	   && (code == GT || code == LE || code == GTU || code == LEU))
     {
-      /* Handle pointers here */
+      /* Handle symbol references here.  Unsigned comparisons will be
+       * wrong if they wrap when the adjustment is made (viz., symbol
+       * value is 0xffff).  Need a special relocation for this? */
       ops[1] =
 	gen_rtx_CONST (HImode, gen_rtx_PLUS (HImode, ops[1], GEN_INT (1)));
 
-- 
1.7.6.4