Enhance the -Wsign-compare handling to suppress the -Wsign-compare warning in the case of a shifted bitfield. PR11572.

llvm-svn: 146634

2 files changed, 7 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 5de124de4de..ebdc8321f70 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -3257,7 +3257,7 @@ IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
   // user has an explicit widening cast, we should treat the value as
   // being of the new, wider type.
   if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
-    if (CE->getCastKind() == CK_NoOp)
+    if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
       return GetExprRange(C, CE->getSubExpr(), MaxWidth);
 
     IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType());
diff --git a/clang/test/Sema/compare.c b/clang/test/Sema/compare.c
index cd973d4885c..03aebb3a046 100644
--- a/clang/test/Sema/compare.c
+++ b/clang/test/Sema/compare.c
@@ -327,3 +327,9 @@ void test10(void) {
   b = (si == (ui = sl)); // expected-warning {{comparison of integers of different signs: 'int' and 'unsigned int'}}
   b = (si == (ui = sl&15));
 }
+
+// PR11572
+struct test11S { unsigned x : 30; };
+int test11(unsigned y, struct test11S *p) {
+  return y > (p->x >> 24); // no-warning
+}