PR debug/7055

[pf3gnuchains/gcc-fork.git] / gcc / tree-chrec.c

diff --git a/gcc/tree-chrec.c b/gcc/tree-chrec.c
index 89e96fd..7a065b6 100644 (file)
--- a/gcc/tree-chrec.c
+++ b/gcc/tree-chrec.c
@@ -579,8 +579,7 @@ chrec_apply (unsigned var,
       /* "{a, +, b} (x)"  ->  "a + b*x".  */
       x = chrec_convert_rhs (type, x, NULL);
       res = chrec_fold_multiply (TREE_TYPE (x), CHREC_RIGHT (chrec), x);
-      if (!integer_zerop (CHREC_LEFT (chrec)))
-       res = chrec_fold_plus (type, CHREC_LEFT (chrec), res);
+      res = chrec_fold_plus (type, CHREC_LEFT (chrec), res);
     }
   
   else if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
@@ -1408,3 +1407,87 @@ scev_direction (const_tree chrec)
   else
     return EV_DIR_GROWS;
 }
+
+/* Iterates over all the components of SCEV, and calls CBCK.  */
+
+void
+for_each_scev_op (tree *scev, bool (*cbck) (tree *, void *), void *data)
+{
+  switch (TREE_CODE_LENGTH (TREE_CODE (*scev)))
+    {
+    case 3:
+      for_each_scev_op (&TREE_OPERAND (*scev, 2), cbck, data);
+
+    case 2:
+      for_each_scev_op (&TREE_OPERAND (*scev, 1), cbck, data);
+      
+    case 1:
+      for_each_scev_op (&TREE_OPERAND (*scev, 0), cbck, data);
+
+    default:
+      cbck (scev, data);
+      break;
+    }
+}
+
+/* Returns true when the operation can be part of a linear
+   expression.  */
+
+static inline bool
+operator_is_linear (tree scev)
+{
+  switch (TREE_CODE (scev))
+    {
+    case INTEGER_CST:
+    case POLYNOMIAL_CHREC:
+    case PLUS_EXPR:
+    case POINTER_PLUS_EXPR:
+    case MULT_EXPR:
+    case MINUS_EXPR:
+    case NEGATE_EXPR:
+    case SSA_NAME:
+    case NON_LVALUE_EXPR:
+    CASE_CONVERT:
+      return true;
+
+    default:
+      return false;
+    }
+}
+
+/* Return true when SCEV is a linear expression.  Linear expressions
+   can contain additions, substractions and multiplications.
+   Multiplications are restricted to constant scaling: "cst * x".  */
+
+bool
+scev_is_linear_expression (tree scev)
+{
+  if (scev == NULL
+      || !operator_is_linear (scev))
+    return false;
+
+  if (TREE_CODE (scev) == MULT_EXPR)
+    return !(tree_contains_chrecs (TREE_OPERAND (scev, 0), NULL)
+            && tree_contains_chrecs (TREE_OPERAND (scev, 1), NULL));
+
+  switch (TREE_CODE_LENGTH (TREE_CODE (scev)))
+    {
+    case 3:
+      return scev_is_linear_expression (TREE_OPERAND (scev, 0))
+       && scev_is_linear_expression (TREE_OPERAND (scev, 1))
+       && scev_is_linear_expression (TREE_OPERAND (scev, 2));
+
+    case 2:
+      return scev_is_linear_expression (TREE_OPERAND (scev, 0))
+       && scev_is_linear_expression (TREE_OPERAND (scev, 1));
+      
+    case 1:
+      return scev_is_linear_expression (TREE_OPERAND (scev, 0));
+
+    case 0:
+      return true;
+
+    default:
+      return false;
+    }
+}