[llvm] r253254 - Add isInteger() to APFloat.

[Stephen Canon via llvm-commits]

Author: scanon
Date: Mon Nov 16 15:52:48 2015
New Revision: 253254

URL: http://llvm.org/viewvc/llvm-project?rev=253254&view=rev
Log:
Add isInteger() to APFloat.

Useful utility function; this wasn't too hard to do before, but also wasn't
obviously discoverable.  Make it explicit.  Reviewed offline by Michael
Gottesman.


Modified:
    llvm/trunk/include/llvm/ADT/APFloat.h
    llvm/trunk/lib/Support/APFloat.cpp
    llvm/trunk/unittests/ADT/APFloatTest.cpp

Modified: llvm/trunk/include/llvm/ADT/APFloat.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APFloat.h?rev=253254&r1=253253&r2=253254&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APFloat.h (original)
+++ llvm/trunk/include/llvm/ADT/APFloat.h Mon Nov 16 15:52:48 2015
@@ -448,6 +448,9 @@ public:
   /// Returns true if and only if the number has the largest possible finite
   /// magnitude in the current semantics.
   bool isLargest() const;
+  
+  /// Returns true if and only if the number is an exact integer.
+  bool isInteger() const;
 
   /// @}
 

Modified: llvm/trunk/lib/Support/APFloat.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APFloat.cpp?rev=253254&r1=253253&r2=253254&view=diff
==============================================================================
--- llvm/trunk/lib/Support/APFloat.cpp (original)
+++ llvm/trunk/lib/Support/APFloat.cpp Mon Nov 16 15:52:48 2015
@@ -768,6 +768,15 @@ APFloat::isLargest() const {
 }
 
 bool
+APFloat::isInteger() const {
+  // This could be made more efficient; I'm going for obviously correct.
+  if (!isFinite()) return false;
+  APFloat truncated = *this;
+  truncated.roundToIntegral(rmTowardZero);
+  return compare(truncated) == cmpEqual;
+}
+
+bool
 APFloat::bitwiseIsEqual(const APFloat &rhs) const {
   if (this == &rhs)
     return true;

Modified: llvm/trunk/unittests/ADT/APFloatTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/APFloatTest.cpp?rev=253254&r1=253253&r2=253254&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/APFloatTest.cpp (original)
+++ llvm/trunk/unittests/ADT/APFloatTest.cpp Mon Nov 16 15:52:48 2015
@@ -1313,7 +1313,21 @@ TEST(APFloatTest, roundToIntegral) {
   P = APFloat::getInf(APFloat::IEEEdouble, true);
   P.roundToIntegral(APFloat::rmTowardZero);
   EXPECT_TRUE(std::isinf(P.convertToDouble()) && P.convertToDouble() < 0.0);
-
+}
+  
+TEST(APFloatTest, isInteger) {
+  APFloat T(-0.0);
+  EXPECT_TRUE(T.isInteger());
+  T = APFloat(3.14159);
+  EXPECT_FALSE(T.isInteger());
+  T = APFloat::getNaN(APFloat::IEEEdouble);
+  EXPECT_FALSE(T.isInteger());
+  T = APFloat::getInf(APFloat::IEEEdouble);
+  EXPECT_FALSE(T.isInteger());
+  T = APFloat::getInf(APFloat::IEEEdouble, true);
+  EXPECT_FALSE(T.isInteger());
+  T = APFloat::getLargest(APFloat::IEEEdouble);
+  EXPECT_TRUE(T.isInteger());
 }
 
 TEST(APFloatTest, getLargest) {