commit 7aa1c321f00d29fdc84e9a03080853aa25dd06fc
author Shuxin Yang <shuxin.llvm@gmail.com> Mon Jan 07 18:59:35 2013 +0000
committer Shuxin Yang <shuxin.llvm@gmail.com> Mon Jan 07 18:59:35 2013 +0000
tree 013045c273e9f818563d36147da2af4326e82721
parent 637582eaf77e6892094cea0bf6b9483f50b5d94e

Implement APFloat::isDenormal()

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171764 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/APFloat.h

diff --git a/include/llvm/ADT/APFloat.h b/include/llvm/ADT/APFloat.h
index 31c6e6a..93d343a 100644
--- a/include/llvm/ADT/APFloat.h
+++ b/include/llvm/ADT/APFloat.h
@@ -327,6 +327,7 @@
     bool isNegative() const { return sign; }
     bool isPosZero() const { return isZero() && !isNegative(); }
     bool isNegZero() const { return isZero() && isNegative(); }
+    bool isDenormal() const;
 
     APFloat& operator=(const APFloat &);
 

lib/Support/APFloat.cpp

diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 17f3891..0e3c619 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -697,6 +697,13 @@
 }
 
 bool
+APFloat::isDenormal() const {
+  return isNormal() && (exponent == semantics->minExponent) &&
+         (APInt::tcExtractBit(significandParts(), 
+                              semantics->precision - 1) == 0);
+}
+
+bool
 APFloat::bitwiseIsEqual(const APFloat &rhs) const {
   if (this == &rhs)
     return true;

unittests/ADT/APFloatTest.cpp

diff --git a/unittests/ADT/APFloatTest.cpp b/unittests/ADT/APFloatTest.cpp
index ff350a7..7345e12 100644
--- a/unittests/ADT/APFloatTest.cpp
+++ b/unittests/ADT/APFloatTest.cpp
@@ -33,6 +33,58 @@
 
 namespace {
 
+TEST(APFloatTest, Denormal) {
+  APFloat::roundingMode rdmd = APFloat::rmNearestTiesToEven;
+
+  // Test single precision
+  {
+    const char *MinNormalStr = "1.17549435082228750797e-38";
+    EXPECT_FALSE(APFloat(APFloat::IEEEsingle, MinNormalStr).isDenormal());
+    EXPECT_FALSE(APFloat(APFloat::IEEEsingle, 0.0).isDenormal());
+
+    APFloat Val2(APFloat::IEEEsingle, 2.0e0);
+    APFloat T(APFloat::IEEEsingle, MinNormalStr);
+    T.divide(Val2, rdmd);
+    EXPECT_TRUE(T.isDenormal());
+  }
+
+  // Test double precision
+  {
+    const char *MinNormalStr = "2.22507385850720138309e-308";
+    EXPECT_FALSE(APFloat(APFloat::IEEEdouble, MinNormalStr).isDenormal());
+    EXPECT_FALSE(APFloat(APFloat::IEEEdouble, 0.0).isDenormal());
+
+    APFloat Val2(APFloat::IEEEdouble, 2.0e0);
+    APFloat T(APFloat::IEEEdouble, MinNormalStr);
+    T.divide(Val2, rdmd);
+    EXPECT_TRUE(T.isDenormal());
+  }
+
+  // Test Intel double-ext
+  {
+    const char *MinNormalStr = "3.36210314311209350626e-4932";
+    EXPECT_FALSE(APFloat(APFloat::x87DoubleExtended, MinNormalStr).isDenormal());
+    EXPECT_FALSE(APFloat(APFloat::x87DoubleExtended, 0.0).isDenormal());
+
+    APFloat Val2(APFloat::x87DoubleExtended, 2.0e0);
+    APFloat T(APFloat::x87DoubleExtended, MinNormalStr);
+    T.divide(Val2, rdmd);
+    EXPECT_TRUE(T.isDenormal());
+  }
+
+  // Test quadruple precision
+  {
+    const char *MinNormalStr = "3.36210314311209350626267781732175260e-4932";
+    EXPECT_FALSE(APFloat(APFloat::IEEEquad, MinNormalStr).isDenormal());
+    EXPECT_FALSE(APFloat(APFloat::IEEEquad, 0.0).isDenormal());
+
+    APFloat Val2(APFloat::IEEEquad, 2.0e0);
+    APFloat T(APFloat::IEEEquad, MinNormalStr);
+    T.divide(Val2, rdmd);
+    EXPECT_TRUE(T.isDenormal());
+  }
+}
+
 TEST(APFloatTest, Zero) {
   EXPECT_EQ(0.0f,  APFloat(0.0f).convertToFloat());
   EXPECT_EQ(-0.0f, APFloat(-0.0f).convertToFloat());