From 8bfb353bb33cd2bcd2ef28e36eb8b90123b153c4 Mon Sep 17 00:00:00 2001
From: Erik Pilkington <erik.pilkington@gmail.com>
Date: Mon, 18 Nov 2019 10:56:05 -0800
Subject: [Sema] Fix a -Wobjc-signed-char-bool false-positive

Unsigned bit-field flags can only have boolean values, so handle that case in
Expr::isKnownToHaveBooleanValue.

rdar://56256999
---
 clang/lib/AST/Expr.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'clang/lib/AST/Expr.cpp')

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 3438c3aadc6..4fd5fed5bee 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -191,6 +191,12 @@ bool Expr::isKnownToHaveBooleanValue() const {
   if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
     return OVE->getSourceExpr()->isKnownToHaveBooleanValue();
 
+  if (const FieldDecl *FD = E->getSourceBitField())
+    if (FD->getType()->isUnsignedIntegerType() &&
+        !FD->getBitWidth()->isValueDependent() &&
+        FD->getBitWidthValue(FD->getASTContext()) == 1)
+      return true;
+
   return false;
 }
 
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