Emit -Wformat properly for bit-field promotions.

Only explicitly look through integer and floating-point promotion where the result type is actually a promotion, which is not always the case for bit-fields in C.

Patch by Bevin Hansson.

llvm-svn: 349497

1 files changed, 21 insertions, 0 deletions

diff --git a/clang/test/Sema/format-strings-bitfield-promotion.cxx b/clang/test/Sema/format-strings-bitfield-promotion.cxx
new file mode 100644
index 00000000000..2309e98066c
--- /dev/null
+++ b/clang/test/Sema/format-strings-bitfield-promotion.cxx
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -fsyntax-only -verify %s
+
+// In C++, the bitfield promotion from long to int does not occur, unlike C.
+// expected-no-diagnostics
+
+int printf(const char *restrict, ...);
+
+struct bitfields {
+  long a : 2;
+  unsigned long b : 2;
+  long c : 32;          // assumes that int is 32 bits
+  unsigned long d : 32; // assumes that int is 32 bits
+} bf;
+
+void bitfield_promotion() {
+  printf("%ld", bf.a);
+  printf("%lu", bf.b);
+  printf("%ld", bf.c);
+  printf("%lu", bf.d);
+}