Index: binutils/gas/config/tc-mips.c
===================================================================
RCS file: /cvsroot/src/gnu/dist/binutils/gas/config/tc-mips.c,v
retrieving revision 1.5
diff -u -r1.5 tc-mips.c
--- binutils/gas/config/tc-mips.c	8 Dec 2004 13:38:10 -0000	1.5
+++ binutils/gas/config/tc-mips.c	6 Feb 2006 19:25:59 -0000
@@ -11080,6 +11080,116 @@
   return 1;
 }
 
+static int is_jump (unsigned long insn)
+{
+	unsigned long op, subop;
+	op = insn >> 26;
+
+	switch (op) {
+	case 16: /* cop0 */
+	case 17: /* cop1 */
+	case 18: /* cop2 */
+		subop = insn >> 21; subop &= 0x1f;
+		if (subop != 8)
+			break;
+		/* bc?f, bc?t, bc?fl, bc?tl */
+		/* fall through */
+	case  1: /* branch or trap */
+	case  2: /* j xx */
+	case  3: /* jal xx */
+	case  4: /* beq s,t, xx */
+	case  5: /* bne s,t, xx */
+	case  6: /* blez s,t, xx */
+	case  7: /* bgtz s,t, xx */
+	case 20: /* beql s,t, xx */
+	case 21: /* bnezl/bnel */
+	case 22: /* blezl s, xx */
+	case 23: /* bgtzl s, xx */
+		return 1;
+	case  0:
+		subop = insn & 0x3f;
+		if ((subop != 8)	/* jr */
+		    && (subop != 9)	/* jalr */
+		    && (subop != 15))	/* sync */
+			break;
+		return 1;
+	}
+
+	return 0;
+}
+
+
+/*
+ * On the R5900, we must warn loops that satisfy all of the following  
+ * conditions: 
+ * 
+ * - a loop consists of less than equal to six instructions(includes 
+ *   branch delay slot). 
+ * - a loop contains only one conditional branch instruction at the 
+ *   end of the loop. 
+ * - a loop does not contain any other branch or jump instructions. 
+ * - a branch delay slot of the loop is not nop. ( EE#2.9 or later ) 
+ *
+ * We need to do this because of a bug in the chip. 
+ */
+
+#define R5900_MINIMUM_LOOP_INSTRUCTIONS		6
+
+/* return 1, if we must warn */
+static int check_short_loop(int loop_target, fixS *fixP)
+{
+	unsigned char *buf;
+	unsigned long insn;
+	int place = fixP->fx_where;  /* place of this jump in bytes */
+	int i;
+	int frag_size;
+
+	/* check loop length */
+	if ((loop_target < 0) ||
+	    (loop_target > R5900_MINIMUM_LOOP_INSTRUCTIONS - 2))
+		return 0;
+
+	/* check jump beyond the boundary */
+	if (loop_target > (place/4))
+		/* XXX: something to be done ?? */
+		return 0;
+
+	/* examin if insn in BD slot is nop */
+	frag_size = fixP->fx_frag->fr_fix + 
+	    fixP->fx_frag->fr_offset * fixP->fx_frag->fr_var;
+
+	if ((place + 4) <= frag_size) {
+		buf = (unsigned char *) (place + fixP->fx_frag->fr_literal);
+		buf += 4;
+		if (target_big_endian)
+			insn = (buf[0] << 24) | (buf[1] << 16) | 
+			    (buf[2] << 8) | buf[3];
+		else
+			insn = (buf[3] << 24) | (buf[2] << 16) | 
+			    (buf[1] << 8) | buf[0];
+
+		if (insn == 0) /* nop */
+			return 0;
+	}
+
+	buf = (unsigned char *) (place + fixP->fx_frag->fr_literal);
+	for (i = 0; i < loop_target ; i++) {
+		buf -= 4;
+		if (target_big_endian)
+			insn = (buf[0] << 24) | (buf[1] << 16) | 
+			    (buf[2] << 8) | buf[3];
+		else
+			insn = (buf[3] << 24) | (buf[2] << 16) | 
+			    (buf[1] << 8) | buf[0];
+
+		if (is_jump(insn))
+			/* jump insn is found */
+			return 0; 
+	}
+
+	return 1;
+}
+
 /* Apply a fixup to the object file.  */
 
 void
@@ -11270,6 +11380,15 @@
       else
 	insn = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 
+	/* check short loop */
+	if (((insn & 0xffff0000) != 0x10000000)			/* beq $0,$0 */
+	    && ((insn & 0xffff0000) != 0x04010000)		/* bgez $0 */
+	    && ((insn & 0xffff0000) != 0x04110000)) {		/* bgezal $0 */
+		if (check_short_loop(-(*valP +1), fixP))
+			as_warn_where (fixP->fx_file, fixP->fx_line,
+			    _("Loop length is too short for R5900."));
+	}
+
       if (*valP + 0x20000 <= 0x3ffff)
 	{
 	  insn |= (*valP >> 2) & 0xffff;
Index: gcc/gcc/toplev.c
===================================================================
RCS file: /cvsroot/src/gnu/dist/gcc/gcc/toplev.c,v
retrieving revision 1.1.1.3
diff -u -r1.1.1.3 toplev.c
--- gcc/gcc/toplev.c	10 Feb 2004 12:09:19 -0000	1.1.1.3
+++ gcc/gcc/toplev.c	6 Feb 2006 19:26:10 -0000
@@ -3561,6 +3561,18 @@
 
   convert_to_eh_region_ranges ();
 
+#ifdef MACHINE_DEPENDENT_REORG_FINAL
+  timevar_push (TV_MACH_DEP);
+  open_dump_file (DFI_mach, decl);
+
+  MACHINE_DEPENDENT_REORG_FINAL (insns);
+
+  close_dump_file (DFI_mach, print_rtl, insns);
+  timevar_pop (TV_MACH_DEP);
+
+  ggc_collect ();
+#endif
+
   /* Shorten branches.  */
   timevar_push (TV_SHORTEN_BRANCH);
   shorten_branches (get_insns ());
Index: gcc/gcc/config/mips/mips-protos.h
===================================================================
RCS file: /cvsroot/src/gnu/dist/gcc/gcc/config/mips/mips-protos.h,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 mips-protos.h
--- gcc/gcc/config/mips/mips-protos.h	23 Jul 2003 02:41:51 -0000	1.1.1.1
+++ gcc/gcc/config/mips/mips-protos.h	6 Feb 2006 19:26:11 -0000
@@ -90,6 +90,7 @@
 extern void		mips_emit_fcc_reload PARAMS ((rtx, rtx, rtx));
 extern void		mips_set_return_address PARAMS ((rtx, rtx));
 extern void		machine_dependent_reorg PARAMS ((rtx));
+extern void		machine_dependent_reorg_final PARAMS ((rtx));
 extern int		mips_address_cost PARAMS ((rtx));
 extern void		mips_count_memory_refs PARAMS ((rtx, int));
 extern HOST_WIDE_INT	mips_debugger_offset PARAMS ((rtx, HOST_WIDE_INT));
Index: gcc/gcc/config/mips/mips.c
===================================================================
RCS file: /cvsroot/src/gnu/dist/gcc/gcc/config/mips/mips.c,v
retrieving revision 1.2
diff -u -r1.2 mips.c
--- gcc/gcc/config/mips/mips.c	25 Oct 2003 21:55:37 -0000	1.2
+++ gcc/gcc/config/mips/mips.c	6 Feb 2006 19:26:19 -0000
@@ -144,6 +144,10 @@
 static int mips_adjust_cost			PARAMS ((rtx, rtx, rtx, int));
 static int mips_issue_rate			PARAMS ((void));
 
+static enum sequence_type r5900_detect_sequence_type PARAMS ((rtx, int *, rtx *,
+							    int *, int));
+static void r5900_lengthen_loops		PARAMS ((rtx, int));
+
 static struct machine_function * mips_init_machine_status PARAMS ((void));
 static void mips_select_section PARAMS ((tree, int, unsigned HOST_WIDE_INT))
 	ATTRIBUTE_UNUSED;
@@ -9743,6 +9747,8 @@
   if (! TARGET_MIPS16)
     return;
 
+  r5900_lengthen_loops (first, 0);
+
   /* If $gp is used, try to remove stores, and replace loads with
      copies from $gp.  */
   if (optimize)
@@ -9932,6 +9938,203 @@
      constant table, but we have no way to prevent that.  */
 }
 
+/*
+ * On the R5900, we must ensure that the compiler never generates loops
+ * that satisfy all of the following conditions:
+ *
+ * - a loop consists of less than equal to six instructions (including the
+ *   branch delay slot).
+ * 
+ * - a loop contains only one conditional branch instruction at the
+ *   end of the loop.
+ *   
+ * - a loop does not contain any other branch or jump instructions.
+ *
+ * - a branch delay slot of the loop is not nop. ( EE#2.9 or later )
+ *
+ * We need to do this because of a bug in the chip.
+ */
+
+#define NOP_INSN_P(INSN) (rtx_equal_p (INSN, gen_nop ()))
+
+enum sequence_type {Jump, Reset, Other};
+
+/* Detect if possible loop jump presents in the sequence */
+
+static enum sequence_type 
+r5900_detect_sequence_type (insn, count_p, jump_insn_p, seen_before, 
+			after_delayed_branch_sched)
+	rtx insn;
+	int *count_p;
+	rtx *jump_insn_p;
+	int *seen_before;
+	int after_delayed_branch_sched;
+{
+  int i;
+  int detect_later = 0;
+
+  for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
+    {
+      rtx v_insn;
+      v_insn = XVECEXP (PATTERN (insn), 0, i);
+
+      switch (GET_CODE (v_insn))
+        {
+	case CODE_LABEL:
+	  seen_before [INSN_UID (v_insn)] = *count_p;
+	  break;
+	case INSN:
+	  /* The attr_length may be bigger than acctual insn length.
+	     So don't use it in the after_delayed_branch_sched phase. */
+	  *count_p  += ( get_attr_length (insn) > 0 
+			&& !after_delayed_branch_sched ) 
+		        ?  get_attr_length (insn) : 4 ; 
+	  if (detect_later)
+	    {
+	      /* inspect BD slot */
+	      if (NOP_INSN_P (PATTERN (v_insn)))
+		return Reset;
+	      return Jump;
+	    }
+	  break;
+	case JUMP_INSN:
+	  *jump_insn_p = v_insn;
+	  detect_later = 1;
+	  break;
+	case CALL_INSN:
+	  return Reset;
+	  break;
+	default:
+	  break;
+	}
+    }
+
+  if (detect_later) 
+    /* Since there's no instruction in the delay slot, the assembler will
+       insert a "nop" later.  */
+    return  Reset;
+
+  return Other;
+}
+
+/* XXX: Fix this.  */
+
+static void
+r5900_lengthen_loops (first, after_delayed_branch_sched)
+  rtx first;
+  int after_delayed_branch_sched;
+{
+  rtx insn;
+  rtx this_jump_insn;
+  const int hazardous_distance = 6;
+  int n = 4;
+  int max_uid = get_max_uid ();
+  int *seen_before = alloca (sizeof seen_before[0] * max_uid);
+  int in_sequence = 0;
+  enum sequence_type result;
+
+  /*bzero ((char *) seen_before, sizeof seen_before[0] * max_uid);*/
+  memset((char *) seen_before, 0, sizeof seen_before[0] * max_uid);
+      
+  for (insn = first; insn; insn = NEXT_INSN (insn))
+    {
+      in_sequence = 0;
+      switch (GET_CODE (insn))
+	{
+	case CODE_LABEL:
+	  seen_before [INSN_UID (insn)] = n;
+	  break;
+
+	case INSN:
+	  if (GET_CODE (PATTERN (insn)) != SEQUENCE ) 
+	    {
+	      /* The attr_length may be bigger than acctual insn length.
+	         So don't use it in the after_delayed_branch_sched phase. */
+	      n += ( get_attr_length (insn) > 0 
+	            && !after_delayed_branch_sched ) 
+		 ?  get_attr_length (insn) : 4 ; 
+	      break;
+	    }
+	  result = r5900_detect_sequence_type(insn, &n, &this_jump_insn, 
+				  seen_before, after_delayed_branch_sched);
+	  switch(result) 
+	    {
+	    case Reset:
+	      goto reset;
+	    case Jump:
+	      in_sequence=1;
+	      goto jump_insn;
+	    case Other:
+	    default:
+	      break;
+	    }
+	  break;
+
+	case JUMP_INSN:
+          this_jump_insn = insn;
+	  in_sequence=0;
+      jump_insn:
+	  if (condjump_p (this_jump_insn))
+	    {
+	      rtx target = condjump_label (this_jump_insn);
+
+	      if (seen_before [INSN_UID (XEXP (target, 0))])
+		{
+		  int distance 
+		    = (n - seen_before [INSN_UID (XEXP (target, 0))]) >> 2;
+
+		  if (!in_sequence) 
+		    {
+		    /* try to insert one nop before jump 
+		     * if distance is in hazardous_distance */
+
+	 	    if  ( distance <=  hazardous_distance )
+		      {
+		        rtx prev_insn = PREV_INSN (this_jump_insn);
+		        while ( prev_insn && ( GET_CODE (prev_insn) != INSN ))
+			    prev_insn =  PREV_INSN (prev_insn);
+			if (prev_insn && ! NOP_INSN_P (PATTERN (prev_insn)))
+			      emit_insn_before (gen_nop (), this_jump_insn);
+
+		      }
+		    }
+		  else 
+		    {
+		      if ( distance <= hazardous_distance ) 
+		        {
+	     	          for (; distance <= hazardous_distance; distance++) 
+		            emit_insn_before (gen_nop(), insn);
+		        }
+		    }
+		}
+	    }
+
+	  /* Falls through */
+
+	case CALL_INSN:
+      reset:
+	  /*bzero ((char *) seen_before, sizeof seen_before[0] * max_uid);*/
+          memset((char *) seen_before, 0, sizeof seen_before[0] * max_uid);
+	  break;
+	    
+	default:
+	  break;
+	}
+    }
+}
+ 
+/* Exported to toplev.c.
+
+   Do a final pass over the function, just before rtl to asm conversion
+   (after "delayed branch scheduling" and "shorten jump").  */
+
+void
+machine_dependent_reorg_final (first)
+     rtx first;
+{
+	r5900_lengthen_loops (first, 1);
+}
+
 /* Return nonzero if X is a SIGN or ZERO extend operator.  */
 int
 extend_operator (x, mode)
Index: gcc/gcc/config/mips/mips.h
===================================================================
RCS file: /cvsroot/src/gnu/dist/gcc/gcc/config/mips/mips.h,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 mips.h
--- gcc/gcc/config/mips/mips.h	23 Jul 2003 02:41:51 -0000	1.1.1.1
+++ gcc/gcc/config/mips/mips.h	6 Feb 2006 19:26:23 -0000
@@ -4611,6 +4611,9 @@
    PC relative loads that are out of range.  */
 #define MACHINE_DEPENDENT_REORG(X) machine_dependent_reorg (X)
 
+/* This is used to lengthen short loops on the r5900. */
+#define MACHINE_DEPENDENT_REORG_FINAL(X) machine_dependent_reorg_final (X)
+
 /* We need to use a special set of functions to handle hard floating
    point code in mips16 mode.  */