diff options
| -rw-r--r-- | lib/Support/APFloat.cpp | 6 | ||||
| -rw-r--r-- | unittests/ADT/APFloatTest.cpp | 15 |
2 files changed, 20 insertions, 1 deletions
diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp index b42a168..ed261a4 100644 --- a/lib/Support/APFloat.cpp +++ b/lib/Support/APFloat.cpp @@ -1770,6 +1770,12 @@ APFloat::opStatus APFloat::roundToIntegral(roundingMode rounding_mode) { opStatus fs; assertArithmeticOK(*semantics); + // 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)) + return opOK; + // The algorithm here is quite simple: we add 2^(p-1), where p is the // precision of our format, and then subtract it back off again. The choice // of rounding modes for the addition/subtraction determines the rounding mode diff --git a/unittests/ADT/APFloatTest.cpp b/unittests/ADT/APFloatTest.cpp index caa288a..00b62fe 100644 --- a/unittests/ADT/APFloatTest.cpp +++ b/unittests/ADT/APFloatTest.cpp @@ -649,7 +649,7 @@ TEST(APFloatTest, exactInverse) { } TEST(APFloatTest, roundToIntegral) { - APFloat T(-0.5), S(3.14), P(0.0); + APFloat T(-0.5), S(3.14), R(APFloat::getLargest(APFloat::IEEEdouble)), P(0.0); P = T; P.roundToIntegral(APFloat::rmTowardZero); @@ -676,6 +676,19 @@ TEST(APFloatTest, roundToIntegral) { P = S; P.roundToIntegral(APFloat::rmNearestTiesToEven); EXPECT_EQ(3.0, P.convertToDouble()); + + P = R; + P.roundToIntegral(APFloat::rmTowardZero); + EXPECT_EQ(R.convertToDouble(), P.convertToDouble()); + P = R; + P.roundToIntegral(APFloat::rmTowardNegative); + EXPECT_EQ(R.convertToDouble(), P.convertToDouble()); + P = R; + P.roundToIntegral(APFloat::rmTowardPositive); + EXPECT_EQ(R.convertToDouble(), P.convertToDouble()); + P = R; + P.roundToIntegral(APFloat::rmNearestTiesToEven); + EXPECT_EQ(R.convertToDouble(), P.convertToDouble()); } TEST(APFloatTest, getLargest) { |