From cab9bc8fba8f48be0e469a7097cd4914a4f617d9 Mon Sep 17 00:00:00 2001
From: Glen Mabey <Glen.Mabey@swri.org>
Date: Thu, 4 May 2017 01:33:12 +0000
Subject: Eliminate ambiguous casts involving qfloat16

The operator double() and operator long double() members of qfloat16
are causing cast ambiguities.  This removes them, leaving only
operator float() which seems to be adequate.

Also, additional arithmetic operator tests were added which without
this removal fail to compile.

Change-Id: Id52a101b318fd754969b3de13c1e528d0aac2387
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/global/qfloat16.h                      | 12 -----
 .../auto/corelib/global/qfloat16/tst_qfloat16.cpp  | 59 +++++++++++++++++++++-
 2 files changed, 57 insertions(+), 14 deletions(-)

diff --git a/src/corelib/global/qfloat16.h b/src/corelib/global/qfloat16.h
index b0272c51c3..054d503249 100644
--- a/src/corelib/global/qfloat16.h
+++ b/src/corelib/global/qfloat16.h
@@ -62,8 +62,6 @@ public:
     Q_DECL_CONSTEXPR inline qfloat16() Q_DECL_NOTHROW : b16(0) { }
     inline qfloat16(float f) Q_DECL_NOTHROW;
     inline operator float() const Q_DECL_NOTHROW;
-    inline operator double() const Q_DECL_NOTHROW;
-    inline operator long double() const Q_DECL_NOTHROW;
 #endif
 
 private:
@@ -153,16 +151,6 @@ inline qfloat16::operator float() const Q_DECL_NOTHROW
 #endif
 }
 
-inline qfloat16::operator double() const Q_DECL_NOTHROW
-{
-    return static_cast<double>(float(*this));
-}
-
-inline qfloat16::operator long double() const Q_DECL_NOTHROW
-{
-    return static_cast<long double>(float(*this));
-}
-
 inline qfloat16 operator-(qfloat16 a) Q_DECL_NOTHROW
 {
     qfloat16 f;
diff --git a/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp b/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
index 3ec863302e..9bd87e3f21 100644
--- a/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
+++ b/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
@@ -44,6 +44,8 @@ private slots:
     void float_cast();
     void float_cast_data();
     void promotionTests();
+    void arithOps_data();
+    void arithOps();
 };
 
 void tst_qfloat16::fuzzyCompare_data()
@@ -198,8 +200,12 @@ void tst_qfloat16::float_cast()
 {
     QFETCH(float, val);
 
-    QVERIFY(qFuzzyCompare(float(qfloat16(val)),val));
-    QVERIFY(qFuzzyCompare(float(qfloat16(-val)),-val));
+    QVERIFY(qFuzzyCompare((float)(qfloat16(val)),val));
+    QVERIFY(qFuzzyCompare((float)(qfloat16(-val)),-val));
+    QVERIFY(qFuzzyCompare((double)(qfloat16(val)),(double)(val)));
+    QVERIFY(qFuzzyCompare((double)(qfloat16(-val)),(double)(-val)));
+    //QVERIFY(qFuzzyCompare((long double)(qfloat16(val)),(long double)(val)));
+    //QVERIFY(qFuzzyCompare((long double)(qfloat16(-val)),(long double)(-val)));
 }
 
 void tst_qfloat16::promotionTests()
@@ -248,6 +254,55 @@ void tst_qfloat16::promotionTests()
     QCOMPARE(sizeof(double),sizeof(qfloat16(1.f)-1));
     QCOMPARE(sizeof(double),sizeof(qfloat16(1.f)*1));
     QCOMPARE(sizeof(double),sizeof(qfloat16(1.f)/1));
+
+    QCOMPARE(QString::number(1.f),QString::number(qfloat16(1.f)));
+}
+
+void tst_qfloat16::arithOps_data()
+{
+    QTest::addColumn<float>("val1");
+    QTest::addColumn<float>("val2");
+
+    QTest::newRow("zero")  << 0.0f << 2.0f;
+    QTest::newRow("one")   << 1.0f << 4.0f;
+    QTest::newRow("ten")   << 10.0f << 20.0f;
+}
+
+void tst_qfloat16::arithOps()
+{
+    QFETCH(float, val1);
+    QFETCH(float, val2);
+
+    QVERIFY(qFuzzyCompare(float(qfloat16(val1) + qfloat16(val2)), val1 + val2));
+    QVERIFY(qFuzzyCompare(float(qfloat16(val1) - qfloat16(val2)), val1 - val2));
+    QVERIFY(qFuzzyCompare(float(qfloat16(val1) * qfloat16(val2)), val1 * val2));
+    QVERIFY(qFuzzyCompare(float(qfloat16(val1) / qfloat16(val2)), val1 / val2));
+
+    QVERIFY(qFuzzyCompare(qfloat16(val1) + val2, val1 + val2));
+    QVERIFY(qFuzzyCompare(qfloat16(val1) - val2, val1 - val2));
+    QVERIFY(qFuzzyCompare(qfloat16(val1) * val2, val1 * val2));
+    QVERIFY(qFuzzyCompare(qfloat16(val1) / val2, val1 / val2));
+
+    QVERIFY(qFuzzyCompare(val1 + qfloat16(val2), val1 + val2));
+    QVERIFY(qFuzzyCompare(val1 - qfloat16(val2), val1 - val2));
+    QVERIFY(qFuzzyCompare(val1 * qfloat16(val2), val1 * val2));
+    QVERIFY(qFuzzyCompare(val1 / qfloat16(val2), val1 / val2));
+
+    float r1 = 0.f;
+    r1 += qfloat16(val2);
+    QVERIFY(qFuzzyCompare(r1,val2));
+
+    float r2 = 0.f;
+    r2 -= qfloat16(val2);
+    QVERIFY(qFuzzyCompare(r2,-val2));
+
+    float r3 = 1.f;
+    r3 *= qfloat16(val2);
+    QVERIFY(qFuzzyCompare(r3,val2));
+
+    float r4 = 1.f;
+    r4 /= qfloat16(val2);
+    QVERIFY(qFuzzyCompare(r4,1.f/val2));
 }
 
 QTEST_APPLESS_MAIN(tst_qfloat16)
-- 
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