IRgen: Fix a horrible bug in pointer to bool conversion, which we were treating

as a truncation not a comparison to null.

llvm-svn: 112021

2 files changed, 15 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 49deb7b365a..6901f9b924f 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1017,18 +1017,23 @@ Value *ScalarExprEmitter::EmitCastExpr(CastExpr *CE) {
 
   case CastExpr::CK_IntegralToPointer: {
     Value *Src = Visit(const_cast<Expr*>(E));
-    
+
     // First, convert to the correct width so that we control the kind of
     // extension.
     const llvm::Type *MiddleTy = CGF.IntPtrTy;
     bool InputSigned = E->getType()->isSignedIntegerType();
     llvm::Value* IntResult =
       Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
-    
+
     return Builder.CreateIntToPtr(IntResult, ConvertType(DestTy));
   }
   case CastExpr::CK_PointerToIntegral: {
     Value *Src = Visit(const_cast<Expr*>(E));
+
+    // Handle conversion to bool correctly.
+    if (DestTy->isBooleanType())
+      return EmitScalarConversion(Visit(E), E->getType(), DestTy);
+
     return Builder.CreatePtrToInt(Src, ConvertType(DestTy));
   }
   case CastExpr::CK_ToVoid: {
diff --git a/clang/test/CodeGen/_Bool-conversion.c b/clang/test/CodeGen/_Bool-conversion.c
new file mode 100644
index 00000000000..fce7ada30a5
--- /dev/null
+++ b/clang/test/CodeGen/_Bool-conversion.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -triple i386 -emit-llvm -O2 -o - %s | FileCheck %s
+
+// CHECK: define i32 @f0()
+// CHECK:  ret i32 1
+// CHECK: }
+
+static _Bool f0_0(void *a0) { return (_Bool) a0; }
+int f0() { return f0_0((void*) 0x2); }