From 71f1ea2c15bbc5b604e20d71191a16d57d106dc0 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault@amd.com>
Date: Thu, 2 Mar 2023 05:44:05 -0400
Subject: [PATCH] APFloat: Add classify

---
 llvm/include/llvm/ADT/APFloat.h    |  3 +++
 llvm/lib/Support/APFloat.cpp       | 13 +++++++++++++
 llvm/unittests/ADT/APFloatTest.cpp | 31 +++++++++++++++++++++++++++++--
 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/llvm/include/llvm/ADT/APFloat.h b/llvm/include/llvm/ADT/APFloat.h
index 3823850..c306465 100644
--- a/llvm/include/llvm/ADT/APFloat.h
+++ b/llvm/include/llvm/ADT/APFloat.h
@@ -1280,6 +1280,9 @@ public:
     APFLOAT_DISPATCH_ON_SEMANTICS(isSmallestNormalized());
   }
 
+  /// Return the FPClassTest which will return true for the value.
+  FPClassTest classify() const;
+
   APFloat &operator=(const APFloat &RHS) = default;
   APFloat &operator=(APFloat &&RHS) = default;
 
diff --git a/llvm/lib/Support/APFloat.cpp b/llvm/lib/Support/APFloat.cpp
index fdf16f6..0505382 100644
--- a/llvm/lib/Support/APFloat.cpp
+++ b/llvm/lib/Support/APFloat.cpp
@@ -5361,6 +5361,19 @@ APFloat::APFloat(const fltSemantics &Semantics, StringRef S)
   consumeError(StatusOrErr.takeError());
 }
 
+FPClassTest APFloat::classify() const {
+  if (isZero())
+    return isNegative() ? fcNegZero : fcPosZero;
+  if (isNormal())
+    return isNegative() ? fcNegNormal : fcPosNormal;
+  if (isDenormal())
+    return isNegative() ? fcNegSubnormal : fcPosSubnormal;
+  if (isInfinity())
+    return isNegative() ? fcNegInf : fcPosInf;
+  assert(isNaN() && "Other class of FP constant");
+  return isSignaling() ? fcSNan : fcQNan;
+}
+
 APFloat::opStatus APFloat::convert(const fltSemantics &ToSemantics,
                                    roundingMode RM, bool *losesInfo) {
   if (&getSemantics() == &ToSemantics) {
diff --git a/llvm/unittests/ADT/APFloatTest.cpp b/llvm/unittests/ADT/APFloatTest.cpp
index 2ec8ebf..79c6a3f 100644
--- a/llvm/unittests/ADT/APFloatTest.cpp
+++ b/llvm/unittests/ADT/APFloatTest.cpp
@@ -53,11 +53,18 @@ TEST(APFloatTest, isSignaling) {
   // positive/negative distinction is included only since the getQNaN/getSNaN
   // API provides the option.
   APInt payload = APInt::getOneBitSet(4, 2);
-  EXPECT_FALSE(APFloat::getQNaN(APFloat::IEEEsingle(), false).isSignaling());
+  APFloat QNan = APFloat::getQNaN(APFloat::IEEEsingle(), false);
+  EXPECT_FALSE(QNan.isSignaling());
+  EXPECT_EQ(fcQNan, QNan.classify());
+
   EXPECT_FALSE(APFloat::getQNaN(APFloat::IEEEsingle(), true).isSignaling());
   EXPECT_FALSE(APFloat::getQNaN(APFloat::IEEEsingle(), false, &payload).isSignaling());
   EXPECT_FALSE(APFloat::getQNaN(APFloat::IEEEsingle(), true, &payload).isSignaling());
-  EXPECT_TRUE(APFloat::getSNaN(APFloat::IEEEsingle(), false).isSignaling());
+
+  APFloat SNan = APFloat::getSNaN(APFloat::IEEEsingle(), false);
+  EXPECT_TRUE(SNan.isSignaling());
+  EXPECT_EQ(fcSNan, SNan.classify());
+
   EXPECT_TRUE(APFloat::getSNaN(APFloat::IEEEsingle(), true).isSignaling());
   EXPECT_TRUE(APFloat::getSNaN(APFloat::IEEEsingle(), false, &payload).isSignaling());
   EXPECT_TRUE(APFloat::getSNaN(APFloat::IEEEsingle(), true, &payload).isSignaling());
@@ -626,6 +633,15 @@ TEST(APFloatTest, Denormal) {
     APFloat T(APFloat::IEEEsingle(), MinNormalStr);
     T.divide(Val2, rdmd);
     EXPECT_TRUE(T.isDenormal());
+    EXPECT_EQ(fcPosSubnormal, T.classify());
+
+
+    const char *NegMinNormalStr = "-1.17549435082228750797e-38";
+    EXPECT_FALSE(APFloat(APFloat::IEEEsingle(), NegMinNormalStr).isDenormal());
+    APFloat NegT(APFloat::IEEEsingle(), NegMinNormalStr);
+    NegT.divide(Val2, rdmd);
+    EXPECT_TRUE(NegT.isDenormal());
+    EXPECT_EQ(fcNegSubnormal, NegT.classify());
   }
 
   // Test double precision
@@ -638,6 +654,7 @@ TEST(APFloatTest, Denormal) {
     APFloat T(APFloat::IEEEdouble(), MinNormalStr);
     T.divide(Val2, rdmd);
     EXPECT_TRUE(T.isDenormal());
+    EXPECT_EQ(fcPosSubnormal, T.classify());
   }
 
   // Test Intel double-ext
@@ -650,6 +667,7 @@ TEST(APFloatTest, Denormal) {
     APFloat T(APFloat::x87DoubleExtended(), MinNormalStr);
     T.divide(Val2, rdmd);
     EXPECT_TRUE(T.isDenormal());
+    EXPECT_EQ(fcPosSubnormal, T.classify());
   }
 
   // Test quadruple precision
@@ -662,6 +680,7 @@ TEST(APFloatTest, Denormal) {
     APFloat T(APFloat::IEEEquad(), MinNormalStr);
     T.divide(Val2, rdmd);
     EXPECT_TRUE(T.isDenormal());
+    EXPECT_EQ(fcPosSubnormal, T.classify());
   }
 }
 
@@ -693,6 +712,8 @@ TEST(APFloatTest, IsSmallestNormalized) {
         APFloat::getSmallestNormalized(Semantics, true);
     EXPECT_TRUE(PosSmallestNormalized.isSmallestNormalized());
     EXPECT_TRUE(NegSmallestNormalized.isSmallestNormalized());
+    EXPECT_EQ(fcPosNormal, PosSmallestNormalized.classify());
+    EXPECT_EQ(fcNegNormal, NegSmallestNormalized.classify());
 
     for (APFloat *Val : {&PosSmallestNormalized, &NegSmallestNormalized}) {
       bool OldSign = Val->isNegative();
@@ -724,6 +745,9 @@ TEST(APFloatTest, Zero) {
   EXPECT_EQ(0.0,  APFloat(0.0).convertToDouble());
   EXPECT_EQ(-0.0, APFloat(-0.0).convertToDouble());
   EXPECT_TRUE(APFloat(-0.0).isNegative());
+
+  EXPECT_EQ(fcPosZero, APFloat(0.0).classify());
+  EXPECT_EQ(fcNegZero, APFloat(-0.0).classify());
 }
 
 TEST(APFloatTest, DecimalStringsWithoutNullTerminators) {
@@ -2195,9 +2219,12 @@ TEST(APFloatTest, isInfinity) {
   EXPECT_TRUE(PosInf.isInfinity());
   EXPECT_TRUE(PosInf.isPosInfinity());
   EXPECT_FALSE(PosInf.isNegInfinity());
+  EXPECT_EQ(fcPosInf, PosInf.classify());
+
   EXPECT_TRUE(NegInf.isInfinity());
   EXPECT_FALSE(NegInf.isPosInfinity());
   EXPECT_TRUE(NegInf.isNegInfinity());
+  EXPECT_EQ(fcNegInf, NegInf.classify());
 
   EXPECT_FALSE(APFloat::getZero(APFloat::IEEEsingle(), false).isInfinity());
   EXPECT_FALSE(APFloat::getNaN(APFloat::IEEEsingle(), false).isInfinity());
-- 
2.7.4