From 6907fbe758d23e1aec4c0a67e7b633d1d855feb4 Mon Sep 17 00:00:00 2001
From: John McCall <rjmccall@apple.com>
Date: Sat, 12 Jun 2010 01:56:02 +0000
Subject: [PATCH] When deciding whether an expression has the boolean nature,
 don't look through explicit casts.  Fixes PR7359.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@105871 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/AST/Expr.cpp      |  4 +++-
 lib/Sema/SemaStmt.cpp |  4 +---
 test/Sema/switch.c    | 11 +++++++++++
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index c38cec32c3..68fcb35c79 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -52,7 +52,9 @@ bool Expr::isKnownToHaveBooleanValue() const {
     }
   }
   
-  if (const CastExpr *CE = dyn_cast<CastExpr>(this))
+  // Only look through implicit casts.  If the user writes
+  // '(int) (a && b)' treat it as an arbitrary int.
+  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(this))
     return CE->getSubExpr()->isKnownToHaveBooleanValue();
   
   if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(this)) {
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 875b160d71..0c510fb1dd 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -400,9 +400,7 @@ static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
 /// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
 /// potentially integral-promoted expression @p expr.
 static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) {
-  const ImplicitCastExpr *ImplicitCast =
-      dyn_cast_or_null<ImplicitCastExpr>(expr);
-  if (ImplicitCast != NULL) {
+  if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) {
     const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr();
     QualType TypeBeforePromotion = ExprBeforePromotion->getType();
     if (TypeBeforePromotion->isIntegralType()) {
diff --git a/test/Sema/switch.c b/test/Sema/switch.c
index 27ad06657e..bb4822916c 100644
--- a/test/Sema/switch.c
+++ b/test/Sema/switch.c
@@ -277,3 +277,14 @@ void test16() {
   case '6': return;
   }
 }
+
+// PR7359
+void test17(int x) {
+  switch (x >= 17) { // expected-warning {{switch condition has boolean value}}
+  case 0: return;
+  }
+
+  switch ((int) (x <= 17)) {
+  case 0: return;
+  }
+}
-- 
2.50.1