Ensure toupper and tolower follow the expected pattern.

If the parameter is not compatible with the LHS, assume this is not really a
builtin function to avoid a trap.

	gcc/
	PR tree-optimization/101741
	* gimple-range-fold.cc (fold_using_range::range_of_builtin_call): Check
	type of parameter for toupper/tolower.

	gcc/testsuite/
	* gcc.dg/pr101741.c: New.

2 files changed, 22 insertions, 0 deletions

diff --git a/gcc/gimple-range-fold.cc b/gcc/gimple-range-fold.cc
index 410bc4d..d3e3e14 100644
--- a/gcc/gimple-range-fold.cc
+++ b/gcc/gimple-range-fold.cc
@@ -894,6 +894,9 @@ fold_using_range::range_of_builtin_call (irange &r, gcall *call,
     case CFN_BUILT_IN_TOUPPER:
       {
 	arg = gimple_call_arg (call, 0);
+	// If the argument isn't compatible with the LHS, do nothing.
+	if (!range_compatible_p (type, TREE_TYPE (arg)))
+	  return false;
 	if (!src.get_operand (r, arg))
 	  return false;
 
@@ -913,6 +916,9 @@ fold_using_range::range_of_builtin_call (irange &r, gcall *call,
      case CFN_BUILT_IN_TOLOWER:
       {
 	arg = gimple_call_arg (call, 0);
+	// If the argument isn't compatible with the LHS, do nothing.
+	if (!range_compatible_p (type, TREE_TYPE (arg)))
+	  return false;
 	if (!src.get_operand (r, arg))
 	  return false;
 
diff --git a/gcc/testsuite/gcc.dg/pr101741.c b/gcc/testsuite/gcc.dg/pr101741.c
new file mode 100644
index 0000000..6587dca
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101741.c
@@ -0,0 +1,16 @@
+/* PR tree-optimization/101741 */
+/* { dg-do compile } */
+/* { dg-options "-O2 " } */
+
+int
+foo (void);
+
+unsigned int
+toupper (int c)
+{
+  c = foo ();
+  while (c)
+    c = toupper (c);
+
+  return c;
+}