tree-vrp.c (compare_values_warnv): Simplify handling of symbolic ranges by calling get_single_symbol and tidy up.

* tree-vrp.c (compare_values_warnv): Simplify handling of symbolic
	ranges by calling get_single_symbol and tidy up.  Look more closely
	into NAME + CST1 vs CST2 comparisons if type overflow is undefined.
ada/
	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Signed_Integer_Subtype>:
	Make same-sized subtypes of signed base types signed.
	* gcc-interface/utils.c (make_type_from_size): Adjust to above change.
	(unchecked_convert): Likewise.

From-SVN: r236548

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2016-05-20  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* tree-vrp.c (compare_values_warnv): Simplify handling of symbolic
+	ranges by calling get_single_symbol and tidy up.  Look more closely
+	into NAME + CST1 vs CST2 comparisons if type overflow is undefined.
+
 2016-05-20  Jeff Law  <law@redhat.com>
 
 	* bitmap.c (bitmap_find_bit): Remove useless test.

gcc/ada/ChangeLog

@@ -1,3 +1,10 @@
+2016-05-20  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Signed_Integer_Subtype>:
+	Make same-sized subtypes of signed base types signed.
+	* gcc-interface/utils.c (make_type_from_size): Adjust to above change.
+	(unchecked_convert): Likewise.
+
 2016-05-16  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Variable>: Do not build

gcc/ada/gcc-interface/decl.c

@@ -1814,7 +1814,12 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
       /* First subtypes of Character are treated as Character; otherwise
 	 this should be an unsigned type if the base type is unsigned or
 	 if the lower bound is constant and non-negative or if the type
-	 is biased.  */
+	 is biased.  However, even if the lower bound is constant and
+	 non-negative, we use a signed type for a subtype with the same
+	 size as its signed base type, because this eliminates useless
+	 conversions to it and gives more leeway to the optimizer; but
+	 this means that we will need to explicitly test for this case
+	 when we change the representation based on the RM size.  */
       if (kind == E_Enumeration_Subtype
 	  && No (First_Literal (Etype (gnat_entity)))
 	  && Esize (gnat_entity) == RM_Size (gnat_entity)
@@ -1822,7 +1827,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
 	  && flag_signed_char)
 	gnu_type = make_signed_type (CHAR_TYPE_SIZE);
       else if (Is_Unsigned_Type (Etype (gnat_entity))
-	       || Is_Unsigned_Type (gnat_entity)
+	       || (Esize (Etype (gnat_entity)) != Esize (gnat_entity)
+		   && Is_Unsigned_Type (gnat_entity))
 	       || Has_Biased_Representation (gnat_entity))
 	gnu_type = make_unsigned_type (esize);
       else

gcc/ada/gcc-interface/utils.c

@@ -1116,7 +1116,14 @@ make_type_from_size (tree type, tree size_tree, bool for_biased)
 	break;
 
       biased_p |= for_biased;
-      if (TYPE_UNSIGNED (type) || biased_p)
+
+      /* The type should be an unsigned type if the original type is unsigned
+	 or if the lower bound is constant and non-negative or if the type is
+	 biased, see E_Signed_Integer_Subtype case of gnat_to_gnu_entity.  */
+      if (TYPE_UNSIGNED (type)
+	  || (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
+	      && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
+	  || biased_p)
 	new_type = make_unsigned_type (size);
       else
 	new_type = make_signed_type (size);
@@ -5111,7 +5118,9 @@ unchecked_convert (tree type, tree expr, bool notrunc_p)
   /* If the result is an integral type whose precision is not equal to its
      size, sign- or zero-extend the result.  We need not do this if the input
      is an integral type of the same precision and signedness or if the output
-     is a biased type or if both the input and output are unsigned.  */
+     is a biased type or if both the input and output are unsigned, or if the
+     lower bound is constant and non-negative, see E_Signed_Integer_Subtype
+     case of gnat_to_gnu_entity.  */
   if (!notrunc_p
       && INTEGRAL_TYPE_P (type)
       && TYPE_RM_SIZE (type)
@@ -5123,7 +5132,10 @@ unchecked_convert (tree type, tree expr, bool notrunc_p)
 				    ? TYPE_RM_SIZE (etype)
 				    : TYPE_SIZE (etype)) == 0)
       && !(code == INTEGER_TYPE && TYPE_BIASED_REPRESENTATION_P (type))
-      && !(TYPE_UNSIGNED (type) && TYPE_UNSIGNED (etype)))
+      && !((TYPE_UNSIGNED (type)
+	    || (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
+		&& tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0))
+	   && TYPE_UNSIGNED (etype)))
     {
       tree base_type
 	= gnat_type_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2016-05-20  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gnat.dg/opt53.adb: New test.
+	* gnat.dg/opt54.adb: Likewise.
+
 2016-05-20  Martin Jambor  <mjambor@suse.cz>
 
 	PR tree-optimization/70884

gcc/testsuite/gnat.dg/opt53.adb

@@ -0,0 +1,12 @@
+-- { dg-do compile }
+-- { dg-options "-O2 -fdump-tree-optimized" }
+
+function Opt53 (Val, Max : Positive) return Positive is
+begin
+   if Val >= Max then
+      return Max;
+   end if;
+   return Val + 1;
+end;
+
+-- { dg-final { scan-tree-dump-not "gnat_rcheck" "optimized" } }

gcc/testsuite/gnat.dg/opt54.adb

@@ -0,0 +1,12 @@
+-- { dg-do compile }
+-- { dg-options "-O2 -fdump-tree-optimized" }
+
+function Opt54 (Val, Max : Integer) return Integer is
+begin
+   if Val >= Max then
+      return Max;
+   end if;
+   return Val + 1;
+end;
+
+-- { dg-final { scan-tree-dump-not "gnat_rcheck" "optimized" } }

gcc/tree-vrp.c

@@ -1187,129 +1187,77 @@ compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
   val2 = fold_convert (TREE_TYPE (val1), val2);
   STRIP_USELESS_TYPE_CONVERSION (val2);
 
-  if ((TREE_CODE (val1) == SSA_NAME
-       || (TREE_CODE (val1) == NEGATE_EXPR
-	   && TREE_CODE (TREE_OPERAND (val1, 0)) == SSA_NAME)
-       || TREE_CODE (val1) == PLUS_EXPR
-       || TREE_CODE (val1) == MINUS_EXPR)
-      && (TREE_CODE (val2) == SSA_NAME
-	  || (TREE_CODE (val2) == NEGATE_EXPR
-	      && TREE_CODE (TREE_OPERAND (val2, 0)) == SSA_NAME)
-	  || TREE_CODE (val2) == PLUS_EXPR
-	  || TREE_CODE (val2) == MINUS_EXPR))
+  const bool overflow_undefined
+    = INTEGRAL_TYPE_P (TREE_TYPE (val1))
+      && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1));
+  tree inv1, inv2;
+  bool neg1, neg2;
+  tree sym1 = get_single_symbol (val1, &neg1, &inv1);
+  tree sym2 = get_single_symbol (val2, &neg2, &inv2);
+
+  /* If VAL1 and VAL2 are of the form '[-]NAME [+ CST]', return -1 or +1
+     accordingly.  If VAL1 and VAL2 don't use the same name, return -2.  */
+  if (sym1 && sym2)
     {
-      tree n1, c1, n2, c2;
-      enum tree_code code1, code2;
-
-      /* If VAL1 and VAL2 are of the form '[-]NAME [+-] CST' or 'NAME',
-	 return -1 or +1 accordingly.  If VAL1 and VAL2 don't use the
-	 same name, return -2.  */
-      if (TREE_CODE (val1) == SSA_NAME || TREE_CODE (val1) == NEGATE_EXPR)
-	{
-	  code1 = SSA_NAME;
-	  n1 = val1;
-	  c1 = NULL_TREE;
-	}
-      else
-	{
-	  code1 = TREE_CODE (val1);
-	  n1 = TREE_OPERAND (val1, 0);
-	  c1 = TREE_OPERAND (val1, 1);
-	  if (tree_int_cst_sgn (c1) == -1)
-	    {
-	      if (is_negative_overflow_infinity (c1))
-		return -2;
-	      c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
-	      if (!c1)
-		return -2;
-	      code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
-	    }
-	}
-
-      if (TREE_CODE (val2) == SSA_NAME || TREE_CODE (val2) == NEGATE_EXPR)
-	{
-	  code2 = SSA_NAME;
-	  n2 = val2;
-	  c2 = NULL_TREE;
-	}
-      else
-	{
-	  code2 = TREE_CODE (val2);
-	  n2 = TREE_OPERAND (val2, 0);
-	  c2 = TREE_OPERAND (val2, 1);
-	  if (tree_int_cst_sgn (c2) == -1)
-	    {
-	      if (is_negative_overflow_infinity (c2))
-		return -2;
-	      c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
-	      if (!c2)
-		return -2;
-	      code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
-	    }
-	}
-
-      /* Both values must use the same name.  */
-      if (TREE_CODE (n1) == NEGATE_EXPR && TREE_CODE (n2) == NEGATE_EXPR)
-	{
-	  n1 = TREE_OPERAND (n1, 0);
-	  n2 = TREE_OPERAND (n2, 0);
-	}
-      if (n1 != n2)
+      /* Both values must use the same name with the same sign.  */
+      if (sym1 != sym2 || neg1 != neg2)
 	return -2;
 
-      if (code1 == SSA_NAME && code2 == SSA_NAME)
-	/* NAME == NAME  */
+      /* [-]NAME + CST == [-]NAME + CST.  */
+      if (inv1 == inv2)
 	return 0;
 
       /* If overflow is defined we cannot simplify more.  */
-      if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
+      if (!overflow_undefined)
 	return -2;
 
       if (strict_overflow_p != NULL
-	  && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
-	  && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
+	  && (!inv1 || !TREE_NO_WARNING (val1))
+	  && (!inv2 || !TREE_NO_WARNING (val2)))
 	*strict_overflow_p = true;
 
-      if (code1 == SSA_NAME)
-	{
-	  if (code2 == PLUS_EXPR)
-	    /* NAME < NAME + CST  */
-	    return -1;
-	  else if (code2 == MINUS_EXPR)
-	    /* NAME > NAME - CST  */
-	    return 1;
-	}
-      else if (code1 == PLUS_EXPR)
-	{
-	  if (code2 == SSA_NAME)
-	    /* NAME + CST > NAME  */
-	    return 1;
-	  else if (code2 == PLUS_EXPR)
-	    /* NAME + CST1 > NAME + CST2, if CST1 > CST2  */
-	    return compare_values_warnv (c1, c2, strict_overflow_p);
-	  else if (code2 == MINUS_EXPR)
-	    /* NAME + CST1 > NAME - CST2  */
-	    return 1;
-	}
-      else if (code1 == MINUS_EXPR)
-	{
-	  if (code2 == SSA_NAME)
-	    /* NAME - CST < NAME  */
-	    return -1;
-	  else if (code2 == PLUS_EXPR)
-	    /* NAME - CST1 < NAME + CST2  */
-	    return -1;
-	  else if (code2 == MINUS_EXPR)
-	    /* NAME - CST1 > NAME - CST2, if CST1 < CST2.  Notice that
-	       C1 and C2 are swapped in the call to compare_values.  */
-	    return compare_values_warnv (c2, c1, strict_overflow_p);
-	}
+      if (!inv1)
+	inv1 = build_int_cst (TREE_TYPE (val1), 0);
+      if (!inv2)
+	inv2 = build_int_cst (TREE_TYPE (val2), 0);
 
-      gcc_unreachable ();
+      return compare_values_warnv (inv1, inv2, strict_overflow_p);
     }
 
-  /* We cannot compare non-constants.  */
-  if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
+  const bool cst1 = is_gimple_min_invariant (val1);
+  const bool cst2 = is_gimple_min_invariant (val2);
+
+  /* If one is of the form '[-]NAME + CST' and the other is constant, then
+     it might be possible to say something depending on the constants.  */
+  if ((sym1 && inv1 && cst2) || (sym2 && inv2 && cst1))
+    {
+      if (!overflow_undefined)
+	return -2;
+
+      if (strict_overflow_p != NULL
+	  && (!sym1 || !TREE_NO_WARNING (val1))
+	  && (!sym2 || !TREE_NO_WARNING (val2)))
+	*strict_overflow_p = true;
+
+      const signop sgn = TYPE_SIGN (TREE_TYPE (val1));
+      tree cst = cst1 ? val1 : val2;
+      tree inv = cst1 ? inv2 : inv1;
+
+      /* Compute the difference between the constants.  If it overflows or
+	 underflows, this means that we can trivially compare the NAME with
+	 it and, consequently, the two values with each other.  */
+      wide_int diff = wi::sub (cst, inv);
+      if (wi::cmp (0, inv, sgn) != wi::cmp (diff, cst, sgn))
+	{
+	  const int res = wi::cmp (cst, inv, sgn);
+	  return cst1 ? res : -res;
+	}
+
+      return -2;
+    }
+
+  /* We cannot say anything more for non-constants.  */
+  if (!cst1 || !cst2)
     return -2;
 
   if (!POINTER_TYPE_P (TREE_TYPE (val1)))