[llvm] r246836 - Fix APInt value initialization to give a zero value as any sane integer type

[Richard Smith via llvm-commits]

Author: rsmith
Date: Thu Sep  3 23:08:36 2015
New Revision: 246836

URL: http://llvm.org/viewvc/llvm-project?rev=246836&view=rev
Log:
Fix APInt value initialization to give a zero value as any sane integer type
should, rather than giving a broken value that doesn't even zero/sign-extend
properly.

Modified:
    llvm/trunk/include/llvm/ADT/APInt.h
    llvm/trunk/unittests/ADT/APIntTest.cpp

Modified: llvm/trunk/include/llvm/ADT/APInt.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APInt.h?rev=246836&r1=246835&r2=246836&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Thu Sep  3 23:08:36 2015
@@ -294,11 +294,12 @@ public:
       delete[] pVal;
   }
 
-  /// \brief Default constructor that creates an uninitialized APInt.
+  /// \brief Default constructor that creates an uninteresting APInt
+  /// representing a 1-bit zero value.
   ///
   /// This is useful for object deserialization (pair this with the static
   ///  method Read).
-  explicit APInt() : BitWidth(1) {}
+  explicit APInt() : BitWidth(1), VAL(0) {}
 
   /// \brief Returns whether this instance allocated memory.
   bool needsCleanup() const { return !isSingleWord(); }

Modified: llvm/trunk/unittests/ADT/APIntTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/APIntTest.cpp?rev=246836&r1=246835&r2=246836&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/APIntTest.cpp (original)
+++ llvm/trunk/unittests/ADT/APIntTest.cpp Thu Sep  3 23:08:36 2015
@@ -17,6 +17,13 @@ using namespace llvm;
 
 namespace {
 
+TEST(APIntTest, ValueInit) {
+  APInt Zero = APInt();
+  EXPECT_TRUE(!Zero);
+  EXPECT_TRUE(!Zero.zext(64));
+  EXPECT_TRUE(!Zero.sext(64));
+}
+
 // Test that APInt shift left works when bitwidth > 64 and shiftamt == 0
 TEST(APIntTest, ShiftLeftByZero) {
   APInt One = APInt::getNullValue(65) + 1;