[llvm-commits] [llvm] r164698 - in /llvm/trunk: lib/Support/APFloat.cpp unittests/ADT/APFloatTest.cpp

[Benjamin Kramer]

Author: d0k
Date: Wed Sep 26 09:06:58 2012
New Revision: 164698

URL: http://llvm.org/viewvc/llvm-project?rev=164698&view=rev
Log:
APFloat::roundToIntegral: Special values don't keep the exponent value up to date, don't rely on it.

Add a couple of unit tests for special floats. Fixes 13929, found by MemorySanitizer.

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

Modified: llvm/trunk/lib/Support/APFloat.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APFloat.cpp?rev=164698&r1=164697&r2=164698&view=diff
==============================================================================
--- llvm/trunk/lib/Support/APFloat.cpp (original)
+++ llvm/trunk/lib/Support/APFloat.cpp Wed Sep 26 09:06:58 2012
@@ -1775,7 +1775,7 @@
   // If the exponent is large enough, we know that this value is already
   // integral, and the arithmetic below would potentially cause it to saturate
   // to +/-Inf.  Bail out early instead.
-  if (exponent+1 >= (int)semanticsPrecision(*semantics))
+  if (category == fcNormal && exponent+1 >= (int)semanticsPrecision(*semantics))
     return opOK;
 
   // The algorithm here is quite simple: we add 2^(p-1), where p is the

Modified: llvm/trunk/unittests/ADT/APFloatTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/APFloatTest.cpp?rev=164698&r1=164697&r2=164698&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/APFloatTest.cpp (original)
+++ llvm/trunk/unittests/ADT/APFloatTest.cpp Wed Sep 26 09:06:58 2012
@@ -689,6 +689,23 @@
   P = R;
   P.roundToIntegral(APFloat::rmNearestTiesToEven);
   EXPECT_EQ(R.convertToDouble(), P.convertToDouble());
+
+  P = APFloat::getZero(APFloat::IEEEdouble);
+  P.roundToIntegral(APFloat::rmTowardZero);
+  EXPECT_EQ(0.0, P.convertToDouble());
+  P = APFloat::getZero(APFloat::IEEEdouble, true);
+  P.roundToIntegral(APFloat::rmTowardZero);
+  EXPECT_EQ(-0.0, P.convertToDouble());
+  P = APFloat::getNaN(APFloat::IEEEdouble);
+  P.roundToIntegral(APFloat::rmTowardZero);
+  EXPECT_TRUE(IsNAN(P.convertToDouble()));
+  P = APFloat::getInf(APFloat::IEEEdouble);
+  P.roundToIntegral(APFloat::rmTowardZero);
+  EXPECT_TRUE(IsInf(P.convertToDouble()) && P.convertToDouble() > 0.0);
+  P = APFloat::getInf(APFloat::IEEEdouble, true);
+  P.roundToIntegral(APFloat::rmTowardZero);
+  EXPECT_TRUE(IsInf(P.convertToDouble()) && P.convertToDouble() < 0.0);
+
 }
 
 TEST(APFloatTest, getLargest) {