local-alloc.c (update_equiv_regs): Use gcc_assert, gcc_unreachable.

	* local-alloc.c (update_equiv_regs): Use gcc_assert, gcc_unreachable.
	(block_alloc, find_free_reg): Likewise.
	* loop-doloop.c (doloop_modify): Likewise.
	* loop-invariant.c (record_use): Likewise.
	* loop-iv.c (get_biv_step_1, get_biv_step, iv_analyze,
	get_iv_value, canon_condition, eliminate_implied_condition,
	eliminate_implied_condition, simplify_using_initial_values,
	shorten_into_mode, canonicalize_iv_subregs,
	iv_number_of_iterations): Likewise.
	* loop-unroll.c (expand_var_during_unrolling): Likewise.
	* loop-unswitch.c (compare_and_jump_seq, unswitch_single_loop,
	unswitch_loop): Likewise.
	* loop.c (INSN_LUID, loop_optimize, rtx_equal_for_loop_p,
	move_movables, replace_call_address, find_and_verify_loops,
	rtx_equal_for_prefetch_p, fold_rtx_mult_add, loop_iterations,
	record_giv, final_giv_value, general_induction_var,
	simplify_giv_expr, extension_within_bounds_p, try_copy_prop,
	loop_giv_dump): Likewise.

From-SVN: r97394

8 files changed, 134 insertions, 155 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e7df520bd53..cbd884f7fd3 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,24 @@
 2005-04-01  Nathan Sidwell  <nathan@codesourcery.com>
 
+	* local-alloc.c (update_equiv_regs): Use gcc_assert, gcc_unreachable.
+	(block_alloc, find_free_reg): Likewise.
+	* loop-doloop.c (doloop_modify): Likewise.
+	* loop-invariant.c (record_use): Likewise.
+	* loop-iv.c (get_biv_step_1, get_biv_step, iv_analyze,
+	get_iv_value, canon_condition, eliminate_implied_condition,
+	eliminate_implied_condition, simplify_using_initial_values,
+	shorten_into_mode, canonicalize_iv_subregs,
+	iv_number_of_iterations): Likewise.
+	* loop-unroll.c (expand_var_during_unrolling): Likewise.
+	* loop-unswitch.c (compare_and_jump_seq, unswitch_single_loop,
+	unswitch_loop): Likewise.
+	* loop.c (INSN_LUID, loop_optimize, rtx_equal_for_loop_p,
+	move_movables, replace_call_address, find_and_verify_loops,
+	rtx_equal_for_prefetch_p, fold_rtx_mult_add, loop_iterations,
+	record_giv, final_giv_value, general_induction_var,
+	simplify_giv_expr, extension_within_bounds_p, try_copy_prop,
+	loop_giv_dump): Likewise.
+
 	* gcov-io.h (GCOV_CHECK, GCOV_CHECK_READING,
 	GCOV_CHECK_WRITING): Remove.
 	(gcov_position, gcov_rewrite): Use gcc_assert.
diff --git a/gcc/local-alloc.c b/gcc/local-alloc.c
index 10117da8adb..3969a86c2ec 100644
--- a/gcc/local-alloc.c
+++ b/gcc/local-alloc.c
@@ -1032,9 +1032,8 @@ update_equiv_regs (void)
 		     once and used once.  (If it were only set, but not used,
 		     flow would have deleted the setting insns.)  Hence
 		     there can only be one insn in reg_equiv[REGNO].init_insns.  */
-		  if (reg_equiv[regno].init_insns == NULL_RTX
-		      || XEXP (reg_equiv[regno].init_insns, 1) != NULL_RTX)
-		    abort ();
+		  gcc_assert (reg_equiv[regno].init_insns
+			      && !XEXP (reg_equiv[regno].init_insns, 1));
 		  equiv_insn = XEXP (reg_equiv[regno].init_insns, 0);
 
 		  /* We may not move instructions that can throw, since
@@ -1196,8 +1195,10 @@ block_alloc (int b)
   while (1)
     {
       if (!NOTE_P (insn))
-	if (++insn_count > max_uid)
-	  abort ();
+	{
+	  ++insn_count;
+	  gcc_assert (insn_count <= max_uid);
+	}
       if (insn == BB_HEAD (BASIC_BLOCK (b)))
 	break;
       insn = PREV_INSN (insn);
@@ -2117,8 +2118,7 @@ find_free_reg (enum reg_class class, enum machine_mode mode, int qtyno,
 #endif
 
   /* Validate our parameters.  */
-  if (born_index < 0 || born_index > dead_index)
-    abort ();
+  gcc_assert (born_index >= 0 && born_index <= dead_index);
 
   /* Don't let a pseudo live in a reg across a function call
      if we might get a nonlocal goto.  */
diff --git a/gcc/loop-doloop.c b/gcc/loop-doloop.c
index 8968b10ab7e..c6ef37e84d6 100644
--- a/gcc/loop-doloop.c
+++ b/gcc/loop-doloop.c
@@ -299,21 +299,17 @@ doloop_modify (struct loop *loop, struct niter_desc *desc,
     {
     case NE:
       /* Currently only NE tests against zero and one are supported.  */
-      if (XEXP (condition, 1) == const1_rtx)
+      noloop = XEXP (condition, 1);
+      if (noloop != const0_rtx)
 	{
+	  gcc_assert (noloop == const1_rtx);
 	  increment_count = true;
-	  noloop = const1_rtx;
 	}
-      else if (XEXP (condition, 1) == const0_rtx)
-       	noloop = const0_rtx;
-      else
-	abort ();
       break;
 
     case GE:
       /* Currently only GE tests against zero are supported.  */
-      if (XEXP (condition, 1) != const0_rtx)
-	abort ();
+      gcc_assert (XEXP (condition, 1) == const0_rtx);
 
       noloop = constm1_rtx;
 
@@ -330,7 +326,7 @@ doloop_modify (struct loop *loop, struct niter_desc *desc,
 
       /* Abort if an invalid doloop pattern has been generated.  */
     default:
-      abort ();
+      gcc_unreachable ();
     }
 
   if (increment_count)
diff --git a/gcc/loop-invariant.c b/gcc/loop-invariant.c
index 92e9d3614f0..7639373ee71 100644
--- a/gcc/loop-invariant.c
+++ b/gcc/loop-invariant.c
@@ -355,8 +355,7 @@ record_use (struct def *def, rtx *use, rtx insn)
 
   if (GET_CODE (*use) == SUBREG)
     use = &SUBREG_REG (*use);
-  if (!REG_P (*use))
-    abort ();
+  gcc_assert (REG_P (*use));
 
   u->pos = use;
   u->insn = insn;
diff --git a/gcc/loop-iv.c b/gcc/loop-iv.c
index 55faf4a7097..09ed73c6324 100644
--- a/gcc/loop-iv.c
+++ b/gcc/loop-iv.c
@@ -793,16 +793,15 @@ get_biv_step_1 (rtx insn, rtx reg,
 
     case SIGN_EXTEND:
     case ZERO_EXTEND:
-      if (GET_MODE (op0) != *inner_mode
-	  || *extend != UNKNOWN
-	  || *outer_step != const0_rtx)
-	abort ();
+      gcc_assert (GET_MODE (op0) == *inner_mode
+		  && *extend == UNKNOWN
+		  && *outer_step == const0_rtx);
 
       *extend = code;
       break;
 
     default:
-      abort ();
+      gcc_unreachable ();
     }
 
   return true;
@@ -826,17 +825,8 @@ get_biv_step (rtx reg, rtx *inner_step, enum machine_mode *inner_mode,
 		       outer_step))
     return false;
 
-  if (*inner_mode != *outer_mode
-      && *extend == UNKNOWN)
-    abort ();
-
-  if (*inner_mode == *outer_mode
-      && *extend != UNKNOWN)
-    abort ();
-
-  if (*inner_mode == *outer_mode
-      && *outer_step != const0_rtx)
-    abort ();
+  gcc_assert ((*inner_mode == *outer_mode) != (*extend != UNKNOWN));
+  gcc_assert (*inner_mode != *outer_mode || *outer_step == const0_rtx);
 
   return true;
 }
@@ -1085,8 +1075,7 @@ iv_analyze (rtx insn, rtx def, struct rtx_iv *iv)
 	  mby = XEXP (rhs, 1);
 	  if (!CONSTANT_P (mby))
 	    {
-	      if (!CONSTANT_P (op0))
-		abort ();
+	      gcc_assert (CONSTANT_P (op0));
 	      tmp = op0;
 	      op0 = mby;
 	      mby = tmp;
@@ -1094,14 +1083,13 @@ iv_analyze (rtx insn, rtx def, struct rtx_iv *iv)
 	  break;
 
 	case ASHIFT:
-	  if (CONSTANT_P (XEXP (rhs, 0)))
-	    abort ();
+	  gcc_assert (!CONSTANT_P (XEXP (rhs, 0)));
 	  op0 = XEXP (rhs, 0);
 	  mby = XEXP (rhs, 1);
 	  break;
 
 	default:
-	  abort ();
+	  gcc_unreachable ();
 	}
 
       amode = GET_MODE (rhs);
@@ -1210,8 +1198,7 @@ get_iv_value (struct rtx_iv *iv, rtx iteration)
 
   /* We would need to generate some if_then_else patterns, and so far
      it is not needed anywhere.  */
-  if (iv->first_special)
-    abort ();
+  gcc_assert (!iv->first_special);
 
   if (iv->step != const0_rtx && iteration != const0_rtx)
     val = simplify_gen_binary (PLUS, iv->extend_mode, iv->base,
@@ -1547,8 +1534,7 @@ canon_condition (rtx cond)
   mode = GET_MODE (op0);
   if (mode == VOIDmode)
     mode = GET_MODE (op1);
-  if (mode == VOIDmode)
-    abort ();
+  gcc_assert (mode != VOIDmode);
 
   if (GET_CODE (op1) == CONST_INT
       && GET_MODE_CLASS (mode) != MODE_CC
@@ -1677,20 +1663,23 @@ simplify_using_condition (rtx cond, rtx *expr, regset altered)
 static void
 eliminate_implied_condition (enum rtx_code op, rtx a, rtx *b)
 {
-  if (op == AND)
+  switch (op)
     {
+    case AND:
       /* If A implies *B, we may replace *B by true.  */
       if (implies_p (a, *b))
 	*b = const_true_rtx;
-    }
-  else if (op == IOR)
-    {
+      break;
+
+    case IOR:
       /* If *B implies A, we may replace *B by false.  */
       if (implies_p (*b, a))
 	*b = const0_rtx;
+      break;
+
+    default:
+      gcc_unreachable ();
     }
-  else
-    abort ();
 }
 
 /* Eliminates the conditions in TAIL that are implied by HEAD.  OP is the
@@ -1731,19 +1720,22 @@ simplify_using_initial_values (struct loop *loop, enum rtx_code op, rtx *expr)
 
       eliminate_implied_conditions (op, &head, tail);
 
-      if (op == AND)
+      switch (op)
 	{
+	case AND:
 	  neutral = const_true_rtx;
 	  aggr = const0_rtx;
-	}
-      else if (op == IOR)
-	{
+	  break;
+
+	case IOR:
 	  neutral = const0_rtx;
 	  aggr = const_true_rtx;
-	}
-      else
-	abort ();
+	  break;
 
+	default:
+	  gcc_unreachable ();
+	}
+      
       simplify_using_initial_values (loop, UNKNOWN, &head);
       if (head == aggr)
 	{
@@ -1770,8 +1762,7 @@ simplify_using_initial_values (struct loop *loop, enum rtx_code op, rtx *expr)
       return;
     }
 
-  if (op != UNKNOWN)
-    abort ();
+  gcc_assert (op == UNKNOWN);
 
   e = loop_preheader_edge (loop);
   if (e->src == ENTRY_BLOCK_PTR)
@@ -1873,7 +1864,7 @@ shorten_into_mode (struct rtx_iv *iv, enum machine_mode mode,
 	break;
 
       default:
-	abort ();
+	gcc_unreachable ();
     }
 
   iv->mode = mode;
@@ -1931,7 +1922,7 @@ canonicalize_iv_subregs (struct rtx_iv *iv0, struct rtx_iv *iv1,
 	break;
 
       default:
-	abort ();
+	gcc_unreachable ();
     }
 
   /* Values of both variables should be computed in the same mode.  These
@@ -2031,15 +2022,13 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
   desc->niter_max = 0;
 
   cond = GET_CODE (condition);
-  if (!COMPARISON_P (condition))
-    abort ();
+  gcc_assert (COMPARISON_P (condition));
 
   mode = GET_MODE (XEXP (condition, 0));
   if (mode == VOIDmode)
     mode = GET_MODE (XEXP (condition, 1));
   /* The constant comparisons should be folded.  */
-  if (mode == VOIDmode)
-    abort ();
+  gcc_assert (mode != VOIDmode);
 
   /* We only handle integers or pointers.  */
   if (GET_MODE_CLASS (mode) != MODE_INT
diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c
index 0112961ce53..e44dae69383 100644
--- a/gcc/loop-unroll.c
+++ b/gcc/loop-unroll.c
@@ -1891,8 +1891,7 @@ expand_var_during_unrolling (struct var_to_expand *ve, rtx insn)
   bool really_new_expansion = false;
   
   set = single_set (insn);
-  if (!set)
-    abort ();
+  gcc_assert (set);
   
   /* Generate a new register only if the expansion limit has not been
      reached.  Else reuse an already existing expansion.  */
diff --git a/gcc/loop-unswitch.c b/gcc/loop-unswitch.c
index bb014bde465..96d80c39477 100644
--- a/gcc/loop-unswitch.c
+++ b/gcc/loop-unswitch.c
@@ -104,13 +104,11 @@ compare_and_jump_seq (rtx op0, rtx op1, enum rtx_code comp, rtx label, int prob,
     {
       /* A hack -- there seems to be no easy generic way how to make a
 	 conditional jump from a ccmode comparison.  */
-      if (!cinsn)
-	abort ();
+      gcc_assert (cinsn);
       cond = XEXP (SET_SRC (pc_set (cinsn)), 0);
-      if (GET_CODE (cond) != comp
-	  || !rtx_equal_p (op0, XEXP (cond, 0))
-	  || !rtx_equal_p (op1, XEXP (cond, 1)))
-	abort ();
+      gcc_assert (GET_CODE (cond) == comp);
+      gcc_assert (rtx_equal_p (op0, XEXP (cond, 0)));
+      gcc_assert (rtx_equal_p (op1, XEXP (cond, 1)));
       emit_jump_insn (copy_insn (PATTERN (cinsn)));
       jump = get_last_insn ();
       JUMP_LABEL (jump) = JUMP_LABEL (cinsn);
@@ -119,8 +117,7 @@ compare_and_jump_seq (rtx op0, rtx op1, enum rtx_code comp, rtx label, int prob,
     }
   else
     {
-      if (cinsn)
-	abort ();
+      gcc_assert (!cinsn);
 
       op0 = force_operand (op0, NULL_RTX);
       op1 = force_operand (op1, NULL_RTX);
@@ -380,8 +377,7 @@ unswitch_single_loop (struct loops *loops, struct loop *loop,
 
   /* Unswitch the loop on this condition.  */
   nloop = unswitch_loop (loops, loop, bbs[i], cond, cinsn);
-  if (!nloop)
-  abort ();
+  gcc_assert (nloop);
 
   /* Invoke itself on modified loops.  */
   unswitch_single_loop (loops, nloop, rconds, num + 1);
@@ -413,18 +409,12 @@ unswitch_loop (struct loops *loops, struct loop *loop, basic_block unswitch_on,
   rtx seq;
 
   /* Some sanity checking.  */
-  if (!flow_bb_inside_loop_p (loop, unswitch_on))
-    abort ();
-  if (EDGE_COUNT (unswitch_on->succs) != 2)
-    abort ();
-  if (!just_once_each_iteration_p (loop, unswitch_on))
-    abort ();
-  if (loop->inner)
-    abort ();
-  if (!flow_bb_inside_loop_p (loop, EDGE_SUCC (unswitch_on, 0)->dest))
-    abort ();
-  if (!flow_bb_inside_loop_p (loop, EDGE_SUCC (unswitch_on, 1)->dest))
-    abort ();
+  gcc_assert (flow_bb_inside_loop_p (loop, unswitch_on));
+  gcc_assert (EDGE_COUNT (unswitch_on->succs) == 2);
+  gcc_assert (just_once_each_iteration_p (loop, unswitch_on));
+  gcc_assert (!loop->inner);
+  gcc_assert (flow_bb_inside_loop_p (loop, EDGE_SUCC (unswitch_on, 0)->dest));
+  gcc_assert (flow_bb_inside_loop_p (loop, EDGE_SUCC (unswitch_on, 1)->dest));
 
   entry = loop_preheader_edge (loop);
 
diff --git a/gcc/loop.c b/gcc/loop.c
index 8a32d2f99b0..6a99e97d38f 100644
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -83,8 +83,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
    of an insn added during loop, since these don't have LUIDs.  */
 
 #define INSN_LUID(INSN)			\
-  (INSN_UID (INSN) < max_uid_for_loop ? uid_luid[INSN_UID (INSN)] \
-   : (abort (), -1))
+  (gcc_assert (INSN_UID (INSN) < max_uid_for_loop), uid_luid[INSN_UID (INSN)])
 
 #define REGNO_FIRST_LUID(REGNO)			\
   (REGNO_FIRST_UID (REGNO) < max_uid_for_loop	\
@@ -869,8 +868,7 @@ loop_optimize (rtx f, FILE *dumpfile, int flags)
 
   /* See if we went too far.  Note that get_max_uid already returns
      one more that the maximum uid of all insn.  */
-  if (get_max_uid () > max_uid_for_loop)
-    abort ();
+  gcc_assert (get_max_uid () <= max_uid_for_loop);
   /* Now reset it to the actual size we need.  See above.  */
   max_uid_for_loop = get_max_uid ();
 
@@ -2117,7 +2115,7 @@ rtx_equal_for_loop_p (rtx x, rtx y, struct loop_movables *movables,
 	     contain anything but integers and other rtx's,
 	     except for within LABEL_REFs and SYMBOL_REFs.  */
 	default:
-	  abort ();
+	  gcc_unreachable ();
 	}
     }
   return 1;
@@ -2310,21 +2308,26 @@ move_movables (struct loop *loop, struct loop_movables *movables,
 
 		  for (count = m->consec; count >= 0; count--)
 		    {
-		      /* If this is the first insn of a library call sequence,
-			 something is very wrong.  */
-		      if (!NOTE_P (p)
-			  && (temp = find_reg_note (p, REG_LIBCALL, NULL_RTX)))
-			abort ();
-
-		      /* If this is the last insn of a libcall sequence, then
-			 delete every insn in the sequence except the last.
-			 The last insn is handled in the normal manner.  */
-		      if (!NOTE_P (p)
-			  && (temp = find_reg_note (p, REG_RETVAL, NULL_RTX)))
+		      if (!NOTE_P (p))
 			{
-			  temp = XEXP (temp, 0);
-			  while (temp != p)
-			    temp = delete_insn (temp);
+			  /* If this is the first insn of a library
+			     call sequence, something is very
+			     wrong.  */
+			  gcc_assert (!find_reg_note
+				      (p, REG_LIBCALL, NULL_RTX));
+
+			  /* If this is the last insn of a libcall
+			     sequence, then delete every insn in the
+			     sequence except the last.  The last insn
+			     is handled in the normal manner.  */
+			  temp = find_reg_note (p, REG_RETVAL, NULL_RTX);
+			  
+			  if (temp)
+			    {
+			      temp = XEXP (temp, 0);
+			      while (temp != p)
+				temp = delete_insn (temp);
+			    }
 			}
 
 		      temp = p;
@@ -2488,8 +2491,7 @@ move_movables (struct loop *loop, struct loop_movables *movables,
 					<< GET_MODE_BITSIZE (m->savemode)))
 				      - 1),
 			     reg, 1, OPTAB_LIB_WIDEN);
-			  if (tem == 0)
-			    abort ();
+			  gcc_assert (tem);
 			  if (tem != reg)
 			    emit_move_insn (reg, tem);
 			  sequence = get_insns ();
@@ -2777,8 +2779,7 @@ replace_call_address (rtx x, rtx reg, rtx addr)
     case MEM:
       /* If this MEM uses a reg other than the one we expected,
 	 something is wrong.  */
-      if (XEXP (x, 0) != reg)
-	abort ();
+      gcc_assert (XEXP (x, 0) == reg);
       XEXP (x, 0) = addr;
       return;
 
@@ -3091,8 +3092,7 @@ find_and_verify_loops (rtx f, struct loops *loops)
 	    break;
 
 	  case NOTE_INSN_LOOP_END:
-	    if (! current_loop)
-	      abort ();
+	    gcc_assert (current_loop);
 
 	    current_loop->end = insn;
 	    current_loop = current_loop->outer;
@@ -3340,8 +3340,7 @@ find_and_verify_loops (rtx f, struct loops *loops)
 
 			    /* If we didn't find it, then something is
 			       wrong.  */
-			    if (! r)
-			      abort ();
+			    gcc_assert (r);
 			  }
 
 			/* P is now a jump outside the loop, so it must be put
@@ -4038,7 +4037,7 @@ rtx_equal_for_prefetch_p (rtx x, rtx y)
 	     contain anything but integers and other rtx's,
 	     except for within LABEL_REFs and SYMBOL_REFs.  */
 	default:
-	  abort ();
+	  gcc_unreachable ();
 	}
     }
   return 1;
@@ -4964,10 +4963,9 @@ fold_rtx_mult_add (rtx mult1, rtx mult2, rtx add1, enum machine_mode mode)
 
   /* The modes must all be the same.  This should always be true.  For now,
      check to make sure.  */
-  if ((GET_MODE (mult1) != mode && GET_MODE (mult1) != VOIDmode)
-      || (GET_MODE (mult2) != mode && GET_MODE (mult2) != VOIDmode)
-      || (GET_MODE (add1) != mode && GET_MODE (add1) != VOIDmode))
-    abort ();
+  gcc_assert (GET_MODE (mult1) == mode || GET_MODE (mult1) == VOIDmode);
+  gcc_assert (GET_MODE (mult2) == mode || GET_MODE (mult2) == VOIDmode);
+  gcc_assert (GET_MODE (add1) == mode || GET_MODE (add1) == VOIDmode);
 
   /* Ensure that if at least one of mult1/mult2 are constant, then mult2
      will be a constant.  */
@@ -5802,9 +5800,8 @@ loop_iterations (struct loop *loop)
      will propagate a new pseudo into the old iteration register but
      this will be marked by having the REG_USERVAR_P bit set.  */
 
-  if ((unsigned) REGNO (iteration_var) >= ivs->n_regs
-      && ! REG_USERVAR_P (iteration_var))
-    abort ();
+  gcc_assert ((unsigned) REGNO (iteration_var) < ivs->n_regs
+	      || REG_USERVAR_P (iteration_var));
 
   /* Determine the initial value of the iteration variable, and the amount
      that it is incremented each loop.  Use the tables constructed by
@@ -5861,8 +5858,7 @@ loop_iterations (struct loop *loop)
 
   if (REG_IV_TYPE (ivs, REGNO (iteration_var)) == BASIC_INDUCT)
     {
-      if (REGNO (iteration_var) >= ivs->n_regs)
-	abort ();
+      gcc_assert (REGNO (iteration_var) < ivs->n_regs);
 
       /* Grab initial value, only useful if it is a constant.  */
       bl = REG_IV_CLASS (ivs, REGNO (iteration_var));
@@ -5883,8 +5879,7 @@ loop_iterations (struct loop *loop)
       struct induction *v = REG_IV_INFO (ivs, REGNO (iteration_var));
       rtx biv_initial_value;
 
-      if (REGNO (v->src_reg) >= ivs->n_regs)
-	abort ();
+      gcc_assert (REGNO (v->src_reg) < ivs->n_regs);
 
       if (!v->always_executed || v->maybe_multiple)
 	{
@@ -5991,7 +5986,7 @@ loop_iterations (struct loop *loop)
       compare_dir = 0;
       break;
     default:
-      abort ();
+      gcc_unreachable ();
     }
 
   /* If the comparison value is an invariant register, then try to find
@@ -6243,18 +6238,17 @@ loop_iterations (struct loop *loop)
      unsigned, because they can be as large as 2^n - 1.  */
 
   inc = INTVAL (increment);
+  gcc_assert (inc);
   if (inc > 0)
     {
       abs_diff = INTVAL (final_value) - INTVAL (initial_value);
       abs_inc = inc;
     }
-  else if (inc < 0)
+  else
     {
       abs_diff = INTVAL (initial_value) - INTVAL (final_value);
       abs_inc = -inc;
     }
-  else
-    abort ();
 
   /* Given that iteration_var is going to iterate over its own mode,
      not HOST_WIDE_INT, disregard higher bits that might have come
@@ -6964,19 +6958,15 @@ record_giv (const struct loop *loop, struct induction *v, rtx insn,
   /* Add the giv to the class of givs computed from one biv.  */
 
   bl = REG_IV_CLASS (ivs, REGNO (src_reg));
-  if (bl)
-    {
-      v->next_iv = bl->giv;
-      bl->giv = v;
-      /* Don't count DEST_ADDR.  This is supposed to count the number of
-	 insns that calculate givs.  */
-      if (type == DEST_REG)
-	bl->giv_count++;
-      bl->total_benefit += benefit;
-    }
-  else
-    /* Fatal error, biv missing for this giv?  */
-    abort ();
+  gcc_assert (bl);
+  v->next_iv = bl->giv;
+  bl->giv = v;
+  
+  /* Don't count DEST_ADDR.  This is supposed to count the number of
+     insns that calculate givs.  */
+  if (type == DEST_REG)
+    bl->giv_count++;
+  bl->total_benefit += benefit;
 
   if (type == DEST_ADDR)
     {
@@ -7191,8 +7181,7 @@ final_giv_value (const struct loop *loop, struct induction *v)
     }
 
   /* Replaceable giv's should never reach here.  */
-  if (v->replaceable)
-    abort ();
+  gcc_assert (!v->replaceable);
 
   /* Check to see if the biv is dead at all loop exits.  */
   if (reg_dead_after_loop (loop, v->dest_reg))
@@ -7756,7 +7745,7 @@ general_induction_var (const struct loop *loop, rtx x, rtx *src_reg,
       break;
 
     default:
-      abort ();
+      gcc_unreachable ();
     }
 
   /* Remove any enclosing USE from ADD_VAL and MULT_VAL (there will be
@@ -7875,7 +7864,7 @@ simplify_giv_expr (const struct loop *loop, rtx x, rtx *ext_val, int *benefit)
 				 ext_val, benefit);
 
 	  default:
-	    abort ();
+	    gcc_unreachable ();
 	  }
 
       /* Each argument must be either REG, PLUS, or MULT.  Convert REG to
@@ -8016,7 +8005,7 @@ simplify_giv_expr (const struct loop *loop, rtx x, rtx *ext_val, int *benefit)
 				    ext_val, benefit);
 
 	default:
-	  abort ();
+	  gcc_unreachable ();
 	}
 
     case ASHIFT:
@@ -8775,7 +8764,7 @@ extension_within_bounds_p (const struct loop *loop, struct iv_class *bl,
       break;
 
     default:
-      abort ();
+      gcc_unreachable ();
     }
 
   return ((!signedp || biv_fits_mode_p (loop, bl, incr, mode, false))
@@ -11112,8 +11101,7 @@ try_copy_prop (const struct loop *loop, rtx replacement, unsigned int regno)
 	  && REG_P (SET_DEST (set))
 	  && REGNO (SET_DEST (set)) == regno)
 	{
-	  if (init_insn)
-	    abort ();
+	  gcc_assert (!init_insn);
 
 	  init_insn = insn;
 	  if (REGNO_FIRST_UID (regno) == INSN_UID (insn))
@@ -11146,8 +11134,7 @@ try_copy_prop (const struct loop *loop, rtx replacement, unsigned int regno)
 	    }
 	}
     }
-  if (! init_insn)
-    abort ();
+  gcc_assert (init_insn);
   if (apply_change_group ())
     {
       if (loop_dump_stream)
@@ -11648,7 +11635,7 @@ loop_giv_dump (const struct induction *v, FILE *file, int verbose)
 	  fprintf (file, " ext tr");
 	  break;
 	default:
-	  abort ();
+	  gcc_unreachable ();
 	}
     }