From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Thu, 8 Nov 2012 13:58:10 +0000 (+0000)
Subject: Drop the limitation to IEEE floating point types from the fdiv of pow2 -> fmul transform.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=6b370e615ca5b3ef17ed4fe4fa891fab1e2bdd9a;p=oota-llvm.git

Drop the limitation to IEEE floating point types from the fdiv of pow2 -> fmul transform.

This is safe for x87 long doubles and ppc double doubles too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167582 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 43c68f4d1d1..7e8b4a3d0d2 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -3553,11 +3553,6 @@ void APFloat::toString(SmallVectorImpl<char> &Str,
 }
 
 bool APFloat::getExactInverse(APFloat *inv) const {
-  // We can only guarantee the existence of an exact inverse for IEEE floats.
-  if (semantics != &IEEEhalf && semantics != &IEEEsingle &&
-      semantics != &IEEEdouble && semantics != &IEEEquad)
-    return false;
-
   // Special floats and denormals have no exact inverse.
   if (category != fcNormal)
     return false;
diff --git a/unittests/ADT/APFloatTest.cpp b/unittests/ADT/APFloatTest.cpp
index 48d5d830193..117b8204b9e 100644
--- a/unittests/ADT/APFloatTest.cpp
+++ b/unittests/ADT/APFloatTest.cpp
@@ -635,6 +635,12 @@ TEST(APFloatTest, exactInverse) {
   EXPECT_TRUE(inv.bitwiseIsEqual(APFloat(0.5)));
   EXPECT_TRUE(APFloat(2.0f).getExactInverse(&inv));
   EXPECT_TRUE(inv.bitwiseIsEqual(APFloat(0.5f)));
+  EXPECT_TRUE(APFloat(APFloat::IEEEquad, "2.0").getExactInverse(&inv));
+  EXPECT_TRUE(inv.bitwiseIsEqual(APFloat(APFloat::IEEEquad, "0.5")));
+  EXPECT_TRUE(APFloat(APFloat::PPCDoubleDouble, "2.0").getExactInverse(&inv));
+  EXPECT_TRUE(inv.bitwiseIsEqual(APFloat(APFloat::PPCDoubleDouble, "0.5")));
+  EXPECT_TRUE(APFloat(APFloat::x87DoubleExtended, "2.0").getExactInverse(&inv));
+  EXPECT_TRUE(inv.bitwiseIsEqual(APFloat(APFloat::x87DoubleExtended, "0.5")));
 
   // FLT_MIN
   EXPECT_TRUE(APFloat(1.17549435e-38f).getExactInverse(&inv));