tree.c (tree_expr_nonnegative_p): New function.

        * tree.c (tree_expr_nonnegative_p): New function.

        * tree.h (tree_expr_nonnegative_p): Declare.

        * c-typeck.c (build_binary_op): Call `tree_expr_nonnegative_p' to
        elide some sign_compare warnings.
        (build_conditional_expr): Likewise.

cp:
        * typeck.c (build_binary_op): Call `tree_expr_nonnegative_p' to elide
        some sign_compare warnings.

From-SVN: r33019

6 files changed, 46 insertions, 13 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3ed3fff..3ff6707 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2000-04-08  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* tree.c (tree_expr_nonnegative_p): New function.
+
+	* tree.h (tree_expr_nonnegative_p): Declare.
+
+	* c-typeck.c (build_binary_op): Call `tree_expr_nonnegative_p' to
+	elide some sign_compare warnings.
+	(build_conditional_expr): Likewise.
+
 Sat Apr  8 00:21:51 EDT 2000  John Wehle  (john@feith.com)
 
 	* i386.md (ashrsi3, ashrhi3, ashrqi3): Fix typo.
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index f66d1b9..0d395a2 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -2416,11 +2416,12 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
 		  else
 		    sop = xop1, uop = xop0;
 
-		  /* Do not warn if the signed quantity is an unsuffixed
-		     integer literal (or some static constant expression
-		     involving such literals) and it is non-negative.  */
-		  if (TREE_CODE (sop) == INTEGER_CST
-		      && tree_int_cst_sgn (sop) >= 0)
+		  /* Do not warn if the signed quantity is an
+		     unsuffixed integer literal (or some static
+		     constant expression involving such literals or a
+		     conditional expression involving such literals)
+		     and it is non-negative.  */
+		  if (tree_expr_nonnegative_p (sop))
 		    /* OK */;
 		  /* Do not warn if the comparison is an equality operation,
 		     the unsigned quantity is an integral constant, and it
@@ -3383,10 +3384,8 @@ build_conditional_expr (ifexp, op1, op2)
 	      /* Do not warn if the signed quantity is an unsuffixed
 		 integer literal (or some static constant expression
 		 involving such literals) and it is non-negative.  */
-	      else if ((unsigned_op2 && TREE_CODE (op1) == INTEGER_CST
-			&& tree_int_cst_sgn (op1) >= 0)
-		       || (unsigned_op1 && TREE_CODE (op2) == INTEGER_CST
-			   && tree_int_cst_sgn (op2) >= 0))
+	      else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
+		       || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
 		/* OK */;
 	      else
 		warning ("signed and unsigned type in conditional expression");
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a23b48d..5759cb6 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2000-04-08  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* typeck.c (build_binary_op): Call `tree_expr_nonnegative_p' to elide
+	some sign_compare warnings.
+
 2000-04-07  Nathan Sidwell  <nathan@codesourcery.com>
 
 	Rename abi::__vmi_class_type_info members.
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 522bc57..74f16b7 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -3960,11 +3960,10 @@ build_binary_op (code, orig_op0, orig_op1)
 	    /* OK */;
 	  /* Do not warn if the signed quantity is an unsuffixed
 	     integer literal (or some static constant expression
+	     involving such literals or a conditional expression
 	     involving such literals) and it is non-negative.  */
-	  else if ((op0_signed && TREE_CODE (orig_op0) == INTEGER_CST
-		    && tree_int_cst_sgn (orig_op0) >= 0)
-		   || (op1_signed && TREE_CODE (orig_op1) == INTEGER_CST
-		       && tree_int_cst_sgn (orig_op1) >= 0))
+	  else if ((op0_signed && tree_expr_nonnegative_p (orig_op0))
+		   || (op1_signed && tree_expr_nonnegative_p (orig_op1)))
 	    /* OK */;
 	  /* Do not warn if the comparison is an equality operation,
 	     the unsigned quantity is an integral constant and it does
diff --git a/gcc/tree.c b/gcc/tree.c
index 53ca207..66078e5 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -4370,6 +4370,25 @@ tree_int_cst_sgn (t)
     return 1;
 }
 
+/* Return true if `t' is known to be non-negative.  */
+
+int
+tree_expr_nonnegative_p (t)
+     tree t;
+{
+  switch (TREE_CODE (t))
+    {
+    case INTEGER_CST:
+      return tree_int_cst_sgn (t) >= 0;
+    case COND_EXPR:
+      return tree_expr_nonnegative_p (TREE_OPERAND (t, 1))
+	&& tree_expr_nonnegative_p (TREE_OPERAND (t, 2));
+    default:
+      /* We don't know sign of `t', so be safe and return false.  */
+      return 0;
+    }
+}
+
 /* Compare two constructor-element-type constants.  Return 1 if the lists
    are known to be equal; otherwise return 0.  */
 
diff --git a/gcc/tree.h b/gcc/tree.h
index 0264ccc..0332102 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -1697,6 +1697,7 @@ extern int host_integerp		PARAMS ((tree, int));
 extern HOST_WIDE_INT tree_low_cst	PARAMS ((tree, int));
 extern int tree_int_cst_msb		PARAMS ((tree));
 extern int tree_int_cst_sgn		PARAMS ((tree));
+extern int tree_expr_nonnegative_p		PARAMS ((tree));
 extern int index_type_equal		PARAMS ((tree, tree));
 extern tree get_inner_array_type	PARAMS ((tree));