Warn when performing 'usual' conversions that require a sign change. This
implements test/Preprocessor/expr_usual_conversions.c, which produces this
output:
expr_usual_conversions.c:5:10: warning: left side of operator converted from negative value to unsigned: -42 to 18446744073709551574
#if (-42 + 0U) / -2
^
expr_usual_conversions.c:5:16: warning: right side of operator converted from negative value to unsigned: -2 to 18446744073709551614
#if (-42 + 0U) / -2
^
llvm-svn: 39406
diff --git a/clang/test/Preprocessor/expr_usual_conversions.c b/clang/test/Preprocessor/expr_usual_conversions.c
new file mode 100644
index 0000000..b2ccc40
--- /dev/null
+++ b/clang/test/Preprocessor/expr_usual_conversions.c
@@ -0,0 +1,8 @@
+// RUN: clang %s -E 2>&1 | grep warning | wc -l | grep 2
+
+#define INTMAX_MIN (-9223372036854775807LL -1)
+
+#if (-42 + 0U) / -2
+foo
+#endif
+