Fix ICE with cast of division by zero (PR c/93348).

Bug 93348 reports an ICE on certain cases of casts of expressions that
may appear only in unevaluated parts of integer constant expressions,
arising from the generation of nested C_MAYBE_CONST_EXPRs.  This patch
fixes it by adding a call to remove_c_maybe_const_expr in the
integer-operands case, as is done in other similar cases.

Bootstrapped with no regressions for x86_64-pc-linux-gnu.

	PR c/93348
gcc/c:
	* c-typeck.c (build_c_cast): Call remove_c_maybe_const_expr on
	argument with integer operands.

gcc/testsuite:
	* gcc.c-torture/compile/pr93348-1.c: New test.

gcc/c/ChangeLog

+2020-01-22  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/93348
+	* c-typeck.c (build_c_cast): Call remove_c_maybe_const_expr on
+	argument with integer operands.
+
 2020-01-16  Kerem Kat  <keremkat@gmail.com>
 
 	PR c/92833

gcc/c/c-typeck.c

@@ -5715,6 +5715,8 @@ build_c_cast (location_t loc, tree type, tree expr)
     expr = TREE_OPERAND (expr, 0);
 
   value = expr;
+  if (int_operands)
+    value = remove_c_maybe_const_expr (value);
 
   if (type == error_mark_node || expr == error_mark_node)
     return error_mark_node;

gcc/testsuite/ChangeLog

+2020-01-22  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/93348
+	* gcc.c-torture/compile/pr93348-1.c: New test.
+
 2020-01-21  David Malcolm  <dmalcolm@redhat.com>
 
 	PR analyzer/93352

gcc/testsuite/gcc.c-torture/compile/pr93348-1.c

+int
+ya (void)
+{
+  return (long int) (1 / 0);
+}