test/cctest/compiler/test-representation-change.cc - fp2-dev/platform/external/v8 - Gitiles

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include <limits>

 #include "src/v8.h"
 #include "test/cctest/cctest.h"
 #include "test/cctest/compiler/graph-builder-tester.h"

 #include "src/compiler/node-matchers.h"
 #include "src/compiler/representation-change.h"
 #include "src/compiler/typer.h"

 using namespace v8::internal;
 using namespace v8::internal::compiler;

 namespace v8 {  // for friendiness.
 namespace internal {
 namespace compiler {

 class RepresentationChangerTester : public HandleAndZoneScope,
                                     public GraphAndBuilders {
  public:
   explicit RepresentationChangerTester(int num_parameters = 0)
       : GraphAndBuilders(main_zone()),
         typer_(main_zone()),
         javascript_(main_zone()),
         jsgraph_(main_graph_, &main_common_, &javascript_, &typer_,
                  &main_machine_),
         changer_(&jsgraph_, &main_simplified_, main_isolate()) {
     Node* s = graph()->NewNode(common()->Start(num_parameters));
     graph()->SetStart(s);
   }

   Typer typer_;
   JSOperatorBuilder javascript_;
   JSGraph jsgraph_;
   RepresentationChanger changer_;

   Isolate* isolate() { return main_isolate(); }
   Graph* graph() { return main_graph_; }
   CommonOperatorBuilder* common() { return &main_common_; }
   JSGraph* jsgraph() { return &jsgraph_; }
   RepresentationChanger* changer() { return &changer_; }

   // TODO(titzer): use ValueChecker / ValueUtil
   void CheckInt32Constant(Node* n, int32_t expected) {
     Int32Matcher m(n);
     CHECK(m.HasValue());
     CHECK_EQ(expected, m.Value());
   }

   void CheckHeapConstant(Node* n, HeapObject* expected) {
     HeapObjectMatcher<HeapObject> m(n);
     CHECK(m.HasValue());
     CHECK_EQ(expected, *m.Value().handle());
   }

   void CheckNumberConstant(Node* n, double expected) {
     NumberMatcher m(n);
     CHECK_EQ(IrOpcode::kNumberConstant, n->opcode());
     CHECK(m.HasValue());
     CHECK_EQ(expected, m.Value());
   }

   Node* Parameter(int index = 0) {
     return graph()->NewNode(common()->Parameter(index), graph()->start());
   }

   void CheckTypeError(MachineTypeUnion from, MachineTypeUnion to) {
     changer()->testing_type_errors_ = true;
     changer()->type_error_ = false;
     Node* n = Parameter(0);
     Node* c = changer()->GetRepresentationFor(n, from, to);
     CHECK(changer()->type_error_);
     CHECK_EQ(n, c);
   }

   void CheckNop(MachineTypeUnion from, MachineTypeUnion to) {
     Node* n = Parameter(0);
     Node* c = changer()->GetRepresentationFor(n, from, to);
     CHECK_EQ(n, c);
   }
 };
 }
 }
 }  // namespace v8::internal::compiler


 // TODO(titzer): add kRepFloat32 when fully supported.
 static const MachineType all_reps[] = {kRepBit, kRepWord32, kRepWord64,
                                        kRepFloat64, kRepTagged};


 // TODO(titzer): lift this to ValueHelper
 static const double double_inputs[] = {
     0.0,   -0.0,    1.0,    -1.0,        0.1,         1.4,    -1.7,
     2,     5,       6,      982983,      888,         -999.8, 3.1e7,
     -2e66, 2.3e124, -12e73, V8_INFINITY, -V8_INFINITY};


 static const int32_t int32_inputs[] = {
     0,      1,                                -1,
     2,      5,                                6,
     982983, 888,                              -999,
     65535,  static_cast<int32_t>(0xFFFFFFFF), static_cast<int32_t>(0x80000000)};


 static const uint32_t uint32_inputs[] = {
     0,      1,   static_cast<uint32_t>(-1),   2,     5,          6,
     982983, 888, static_cast<uint32_t>(-999), 65535, 0xFFFFFFFF, 0x80000000};


 TEST(BoolToBit_constant) {
   RepresentationChangerTester r;

   Node* true_node = r.jsgraph()->TrueConstant();
   Node* true_bit =
       r.changer()->GetRepresentationFor(true_node, kRepTagged, kRepBit);
   r.CheckInt32Constant(true_bit, 1);

   Node* false_node = r.jsgraph()->FalseConstant();
   Node* false_bit =
       r.changer()->GetRepresentationFor(false_node, kRepTagged, kRepBit);
   r.CheckInt32Constant(false_bit, 0);
 }


 TEST(BitToBool_constant) {
   RepresentationChangerTester r;

   for (int i = -5; i < 5; i++) {
     Node* node = r.jsgraph()->Int32Constant(i);
     Node* val = r.changer()->GetRepresentationFor(node, kRepBit, kRepTagged);
     r.CheckHeapConstant(val, i == 0 ? r.isolate()->heap()->false_value()
                                     : r.isolate()->heap()->true_value());
   }
 }


 TEST(ToTagged_constant) {
   RepresentationChangerTester r;

   for (size_t i = 0; i < arraysize(double_inputs); i++) {
     Node* n = r.jsgraph()->Float64Constant(double_inputs[i]);
     Node* c = r.changer()->GetRepresentationFor(n, kRepFloat64, kRepTagged);
     r.CheckNumberConstant(c, double_inputs[i]);
   }

   for (size_t i = 0; i < arraysize(int32_inputs); i++) {
     Node* n = r.jsgraph()->Int32Constant(int32_inputs[i]);
     Node* c = r.changer()->GetRepresentationFor(n, kRepWord32 | kTypeInt32,
                                                 kRepTagged);
     r.CheckNumberConstant(c, static_cast<double>(int32_inputs[i]));
   }

   for (size_t i = 0; i < arraysize(uint32_inputs); i++) {
     Node* n = r.jsgraph()->Int32Constant(uint32_inputs[i]);
     Node* c = r.changer()->GetRepresentationFor(n, kRepWord32 | kTypeUint32,
                                                 kRepTagged);
     r.CheckNumberConstant(c, static_cast<double>(uint32_inputs[i]));
   }
 }


 static void CheckChange(IrOpcode::Value expected, MachineTypeUnion from,
                         MachineTypeUnion to) {
   RepresentationChangerTester r;

   Node* n = r.Parameter();
   Node* c = r.changer()->GetRepresentationFor(n, from, to);

   CHECK_NE(c, n);
   CHECK_EQ(expected, c->opcode());
   CHECK_EQ(n, c->InputAt(0));
 }


 TEST(SingleChanges) {
   CheckChange(IrOpcode::kChangeBoolToBit, kRepTagged, kRepBit);
   CheckChange(IrOpcode::kChangeBitToBool, kRepBit, kRepTagged);

   CheckChange(IrOpcode::kChangeInt32ToTagged, kRepWord32 | kTypeInt32,
               kRepTagged);
   CheckChange(IrOpcode::kChangeUint32ToTagged, kRepWord32 | kTypeUint32,
               kRepTagged);
   CheckChange(IrOpcode::kChangeFloat64ToTagged, kRepFloat64, kRepTagged);

   CheckChange(IrOpcode::kChangeTaggedToInt32, kRepTagged | kTypeInt32,
               kRepWord32);
   CheckChange(IrOpcode::kChangeTaggedToUint32, kRepTagged | kTypeUint32,
               kRepWord32);
   CheckChange(IrOpcode::kChangeTaggedToFloat64, kRepTagged, kRepFloat64);

   // Int32,Uint32 <-> Float64 are actually machine conversions.
   CheckChange(IrOpcode::kChangeInt32ToFloat64, kRepWord32 | kTypeInt32,
               kRepFloat64);
   CheckChange(IrOpcode::kChangeUint32ToFloat64, kRepWord32 | kTypeUint32,
               kRepFloat64);
   CheckChange(IrOpcode::kChangeFloat64ToInt32, kRepFloat64 | kTypeInt32,
               kRepWord32);
   CheckChange(IrOpcode::kChangeFloat64ToUint32, kRepFloat64 | kTypeUint32,
               kRepWord32);
 }


 TEST(SignednessInWord32) {
   RepresentationChangerTester r;

   // TODO(titzer): assume that uses of a word32 without a sign mean kTypeInt32.
   CheckChange(IrOpcode::kChangeTaggedToInt32, kRepTagged,
               kRepWord32 | kTypeInt32);
   CheckChange(IrOpcode::kChangeTaggedToUint32, kRepTagged,
               kRepWord32 | kTypeUint32);
   CheckChange(IrOpcode::kChangeInt32ToFloat64, kRepWord32, kRepFloat64);
   CheckChange(IrOpcode::kChangeFloat64ToInt32, kRepFloat64, kRepWord32);
 }


 TEST(Nops) {
   RepresentationChangerTester r;

   // X -> X is always a nop for any single representation X.
   for (size_t i = 0; i < arraysize(all_reps); i++) {
     r.CheckNop(all_reps[i], all_reps[i]);
   }

   // 32-bit floats.
   r.CheckNop(kRepFloat32, kRepFloat32);
   r.CheckNop(kRepFloat32 | kTypeNumber, kRepFloat32);
   r.CheckNop(kRepFloat32, kRepFloat32 | kTypeNumber);

   // 32-bit or 64-bit words can be used as branch conditions (kRepBit).
   r.CheckNop(kRepWord32, kRepBit);
   r.CheckNop(kRepWord32, kRepBit | kTypeBool);
   r.CheckNop(kRepWord64, kRepBit);
   r.CheckNop(kRepWord64, kRepBit | kTypeBool);

   // 32-bit words can be used as smaller word sizes and vice versa, because
   // loads from memory implicitly sign or zero extend the value to the
   // full machine word size, and stores implicitly truncate.
   r.CheckNop(kRepWord32, kRepWord8);
   r.CheckNop(kRepWord32, kRepWord16);
   r.CheckNop(kRepWord32, kRepWord32);
   r.CheckNop(kRepWord8, kRepWord32);
   r.CheckNop(kRepWord16, kRepWord32);

   // kRepBit (result of comparison) is implicitly a wordish thing.
   r.CheckNop(kRepBit, kRepWord8);
   r.CheckNop(kRepBit | kTypeBool, kRepWord8);
   r.CheckNop(kRepBit, kRepWord16);
   r.CheckNop(kRepBit | kTypeBool, kRepWord16);
   r.CheckNop(kRepBit, kRepWord32);
   r.CheckNop(kRepBit | kTypeBool, kRepWord32);
   r.CheckNop(kRepBit, kRepWord64);
   r.CheckNop(kRepBit | kTypeBool, kRepWord64);
 }


 TEST(TypeErrors) {
   RepresentationChangerTester r;

   // Floats cannot be implicitly converted to/from comparison conditions.
   r.CheckTypeError(kRepFloat64, kRepBit);
   r.CheckTypeError(kRepFloat64, kRepBit | kTypeBool);
   r.CheckTypeError(kRepBit, kRepFloat64);
   r.CheckTypeError(kRepBit | kTypeBool, kRepFloat64);

   // Floats cannot be implicitly converted to/from comparison conditions.
   r.CheckTypeError(kRepFloat32, kRepBit);
   r.CheckTypeError(kRepFloat32, kRepBit | kTypeBool);
   r.CheckTypeError(kRepBit, kRepFloat32);
   r.CheckTypeError(kRepBit | kTypeBool, kRepFloat32);

   // Word64 is internal and shouldn't be implicitly converted.
   r.CheckTypeError(kRepWord64, kRepTagged | kTypeBool);
   r.CheckTypeError(kRepWord64, kRepTagged);
   r.CheckTypeError(kRepWord64, kRepTagged | kTypeBool);
   r.CheckTypeError(kRepTagged, kRepWord64);
   r.CheckTypeError(kRepTagged | kTypeBool, kRepWord64);

   // Word64 / Word32 shouldn't be implicitly converted.
   r.CheckTypeError(kRepWord64, kRepWord32);
   r.CheckTypeError(kRepWord32, kRepWord64);
   r.CheckTypeError(kRepWord64, kRepWord32 | kTypeInt32);
   r.CheckTypeError(kRepWord32 | kTypeInt32, kRepWord64);
   r.CheckTypeError(kRepWord64, kRepWord32 | kTypeUint32);
   r.CheckTypeError(kRepWord32 | kTypeUint32, kRepWord64);

   for (size_t i = 0; i < arraysize(all_reps); i++) {
     for (size_t j = 0; j < arraysize(all_reps); j++) {
       if (i == j) continue;
       // Only a single from representation is allowed.
       r.CheckTypeError(all_reps[i] | all_reps[j], kRepTagged);
     }
   }

   // TODO(titzer): Float32 representation changes trigger type errors now.
   // Enforce current behavior to test all paths through representation changer.
   for (size_t i = 0; i < arraysize(all_reps); i++) {
     r.CheckTypeError(all_reps[i], kRepFloat32);
     r.CheckTypeError(kRepFloat32, all_reps[i]);
   }
 }
	// Copyright 2014 the V8 project authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include <limits>

	#include "src/v8.h"
	#include "test/cctest/cctest.h"
	#include "test/cctest/compiler/graph-builder-tester.h"

	#include "src/compiler/node-matchers.h"
	#include "src/compiler/representation-change.h"
	#include "src/compiler/typer.h"

	using namespace v8::internal;
	using namespace v8::internal::compiler;

	namespace v8 { // for friendiness.
	namespace internal {
	namespace compiler {

	class RepresentationChangerTester : public HandleAndZoneScope,
	public GraphAndBuilders {
	public:
	explicit RepresentationChangerTester(int num_parameters = 0)
	: GraphAndBuilders(main_zone()),
	typer_(main_zone()),
	javascript_(main_zone()),
	jsgraph_(main_graph_, &main_common_, &javascript_, &typer_,
	&main_machine_),
	changer_(&jsgraph_, &main_simplified_, main_isolate()) {
	Node* s = graph()->NewNode(common()->Start(num_parameters));
	graph()->SetStart(s);
	}

	Typer typer_;
	JSOperatorBuilder javascript_;
	JSGraph jsgraph_;
	RepresentationChanger changer_;

	Isolate* isolate() { return main_isolate(); }
	Graph* graph() { return main_graph_; }
	CommonOperatorBuilder* common() { return &main_common_; }
	JSGraph* jsgraph() { return &jsgraph_; }
	RepresentationChanger* changer() { return &changer_; }

	// TODO(titzer): use ValueChecker / ValueUtil
	void CheckInt32Constant(Node* n, int32_t expected) {
	Int32Matcher m(n);
	CHECK(m.HasValue());
	CHECK_EQ(expected, m.Value());
	}

	void CheckHeapConstant(Node* n, HeapObject* expected) {
	HeapObjectMatcher<HeapObject> m(n);
	CHECK(m.HasValue());
	CHECK_EQ(expected, *m.Value().handle());
	}

	void CheckNumberConstant(Node* n, double expected) {
	NumberMatcher m(n);
	CHECK_EQ(IrOpcode::kNumberConstant, n->opcode());
	CHECK(m.HasValue());
	CHECK_EQ(expected, m.Value());
	}

	Node* Parameter(int index = 0) {
	return graph()->NewNode(common()->Parameter(index), graph()->start());
	}

	void CheckTypeError(MachineTypeUnion from, MachineTypeUnion to) {
	changer()->testing_type_errors_ = true;
	changer()->type_error_ = false;
	Node* n = Parameter(0);
	Node* c = changer()->GetRepresentationFor(n, from, to);
	CHECK(changer()->type_error_);
	CHECK_EQ(n, c);
	}

	void CheckNop(MachineTypeUnion from, MachineTypeUnion to) {
	Node* n = Parameter(0);
	Node* c = changer()->GetRepresentationFor(n, from, to);
	CHECK_EQ(n, c);
	}
	};
	}
	}
	} // namespace v8::internal::compiler


	// TODO(titzer): add kRepFloat32 when fully supported.
	static const MachineType all_reps[] = {kRepBit, kRepWord32, kRepWord64,
	kRepFloat64, kRepTagged};


	// TODO(titzer): lift this to ValueHelper
	static const double double_inputs[] = {
	0.0, -0.0, 1.0, -1.0, 0.1, 1.4, -1.7,
	2, 5, 6, 982983, 888, -999.8, 3.1e7,
	-2e66, 2.3e124, -12e73, V8_INFINITY, -V8_INFINITY};


	static const int32_t int32_inputs[] = {
	0, 1, -1,
	2, 5, 6,
	982983, 888, -999,
	65535, static_cast<int32_t>(0xFFFFFFFF), static_cast<int32_t>(0x80000000)};


	static const uint32_t uint32_inputs[] = {
	0, 1, static_cast<uint32_t>(-1), 2, 5, 6,
	982983, 888, static_cast<uint32_t>(-999), 65535, 0xFFFFFFFF, 0x80000000};


	TEST(BoolToBit_constant) {
	RepresentationChangerTester r;

	Node* true_node = r.jsgraph()->TrueConstant();
	Node* true_bit =
	r.changer()->GetRepresentationFor(true_node, kRepTagged, kRepBit);
	r.CheckInt32Constant(true_bit, 1);

	Node* false_node = r.jsgraph()->FalseConstant();
	Node* false_bit =
	r.changer()->GetRepresentationFor(false_node, kRepTagged, kRepBit);
	r.CheckInt32Constant(false_bit, 0);
	}


	TEST(BitToBool_constant) {
	RepresentationChangerTester r;

	for (int i = -5; i < 5; i++) {
	Node* node = r.jsgraph()->Int32Constant(i);
	Node* val = r.changer()->GetRepresentationFor(node, kRepBit, kRepTagged);
	r.CheckHeapConstant(val, i == 0 ? r.isolate()->heap()->false_value()
	: r.isolate()->heap()->true_value());
	}
	}


	TEST(ToTagged_constant) {
	RepresentationChangerTester r;

	for (size_t i = 0; i < arraysize(double_inputs); i++) {
	Node* n = r.jsgraph()->Float64Constant(double_inputs[i]);
	Node* c = r.changer()->GetRepresentationFor(n, kRepFloat64, kRepTagged);
	r.CheckNumberConstant(c, double_inputs[i]);
	}

	for (size_t i = 0; i < arraysize(int32_inputs); i++) {
	Node* n = r.jsgraph()->Int32Constant(int32_inputs[i]);
	Node* c = r.changer()->GetRepresentationFor(n, kRepWord32 \| kTypeInt32,
	kRepTagged);
	r.CheckNumberConstant(c, static_cast<double>(int32_inputs[i]));
	}

	for (size_t i = 0; i < arraysize(uint32_inputs); i++) {
	Node* n = r.jsgraph()->Int32Constant(uint32_inputs[i]);
	Node* c = r.changer()->GetRepresentationFor(n, kRepWord32 \| kTypeUint32,
	kRepTagged);
	r.CheckNumberConstant(c, static_cast<double>(uint32_inputs[i]));
	}
	}


	static void CheckChange(IrOpcode::Value expected, MachineTypeUnion from,
	MachineTypeUnion to) {
	RepresentationChangerTester r;

	Node* n = r.Parameter();
	Node* c = r.changer()->GetRepresentationFor(n, from, to);

	CHECK_NE(c, n);
	CHECK_EQ(expected, c->opcode());
	CHECK_EQ(n, c->InputAt(0));
	}


	TEST(SingleChanges) {
	CheckChange(IrOpcode::kChangeBoolToBit, kRepTagged, kRepBit);
	CheckChange(IrOpcode::kChangeBitToBool, kRepBit, kRepTagged);

	CheckChange(IrOpcode::kChangeInt32ToTagged, kRepWord32 \| kTypeInt32,
	kRepTagged);
	CheckChange(IrOpcode::kChangeUint32ToTagged, kRepWord32 \| kTypeUint32,
	kRepTagged);
	CheckChange(IrOpcode::kChangeFloat64ToTagged, kRepFloat64, kRepTagged);

	CheckChange(IrOpcode::kChangeTaggedToInt32, kRepTagged \| kTypeInt32,
	kRepWord32);
	CheckChange(IrOpcode::kChangeTaggedToUint32, kRepTagged \| kTypeUint32,
	kRepWord32);
	CheckChange(IrOpcode::kChangeTaggedToFloat64, kRepTagged, kRepFloat64);

	// Int32,Uint32 <-> Float64 are actually machine conversions.
	CheckChange(IrOpcode::kChangeInt32ToFloat64, kRepWord32 \| kTypeInt32,
	kRepFloat64);
	CheckChange(IrOpcode::kChangeUint32ToFloat64, kRepWord32 \| kTypeUint32,
	kRepFloat64);
	CheckChange(IrOpcode::kChangeFloat64ToInt32, kRepFloat64 \| kTypeInt32,
	kRepWord32);
	CheckChange(IrOpcode::kChangeFloat64ToUint32, kRepFloat64 \| kTypeUint32,
	kRepWord32);
	}


	TEST(SignednessInWord32) {
	RepresentationChangerTester r;

	// TODO(titzer): assume that uses of a word32 without a sign mean kTypeInt32.
	CheckChange(IrOpcode::kChangeTaggedToInt32, kRepTagged,
	kRepWord32 \| kTypeInt32);
	CheckChange(IrOpcode::kChangeTaggedToUint32, kRepTagged,
	kRepWord32 \| kTypeUint32);
	CheckChange(IrOpcode::kChangeInt32ToFloat64, kRepWord32, kRepFloat64);
	CheckChange(IrOpcode::kChangeFloat64ToInt32, kRepFloat64, kRepWord32);
	}


	TEST(Nops) {
	RepresentationChangerTester r;

	// X -> X is always a nop for any single representation X.
	for (size_t i = 0; i < arraysize(all_reps); i++) {
	r.CheckNop(all_reps[i], all_reps[i]);
	}

	// 32-bit floats.
	r.CheckNop(kRepFloat32, kRepFloat32);
	r.CheckNop(kRepFloat32 \| kTypeNumber, kRepFloat32);
	r.CheckNop(kRepFloat32, kRepFloat32 \| kTypeNumber);

	// 32-bit or 64-bit words can be used as branch conditions (kRepBit).
	r.CheckNop(kRepWord32, kRepBit);
	r.CheckNop(kRepWord32, kRepBit \| kTypeBool);
	r.CheckNop(kRepWord64, kRepBit);
	r.CheckNop(kRepWord64, kRepBit \| kTypeBool);

	// 32-bit words can be used as smaller word sizes and vice versa, because
	// loads from memory implicitly sign or zero extend the value to the
	// full machine word size, and stores implicitly truncate.
	r.CheckNop(kRepWord32, kRepWord8);
	r.CheckNop(kRepWord32, kRepWord16);
	r.CheckNop(kRepWord32, kRepWord32);
	r.CheckNop(kRepWord8, kRepWord32);
	r.CheckNop(kRepWord16, kRepWord32);

	// kRepBit (result of comparison) is implicitly a wordish thing.
	r.CheckNop(kRepBit, kRepWord8);
	r.CheckNop(kRepBit \| kTypeBool, kRepWord8);
	r.CheckNop(kRepBit, kRepWord16);
	r.CheckNop(kRepBit \| kTypeBool, kRepWord16);
	r.CheckNop(kRepBit, kRepWord32);
	r.CheckNop(kRepBit \| kTypeBool, kRepWord32);
	r.CheckNop(kRepBit, kRepWord64);
	r.CheckNop(kRepBit \| kTypeBool, kRepWord64);
	}


	TEST(TypeErrors) {
	RepresentationChangerTester r;

	// Floats cannot be implicitly converted to/from comparison conditions.
	r.CheckTypeError(kRepFloat64, kRepBit);
	r.CheckTypeError(kRepFloat64, kRepBit \| kTypeBool);
	r.CheckTypeError(kRepBit, kRepFloat64);
	r.CheckTypeError(kRepBit \| kTypeBool, kRepFloat64);

	// Floats cannot be implicitly converted to/from comparison conditions.
	r.CheckTypeError(kRepFloat32, kRepBit);
	r.CheckTypeError(kRepFloat32, kRepBit \| kTypeBool);
	r.CheckTypeError(kRepBit, kRepFloat32);
	r.CheckTypeError(kRepBit \| kTypeBool, kRepFloat32);

	// Word64 is internal and shouldn't be implicitly converted.
	r.CheckTypeError(kRepWord64, kRepTagged \| kTypeBool);
	r.CheckTypeError(kRepWord64, kRepTagged);
	r.CheckTypeError(kRepWord64, kRepTagged \| kTypeBool);
	r.CheckTypeError(kRepTagged, kRepWord64);
	r.CheckTypeError(kRepTagged \| kTypeBool, kRepWord64);

	// Word64 / Word32 shouldn't be implicitly converted.
	r.CheckTypeError(kRepWord64, kRepWord32);
	r.CheckTypeError(kRepWord32, kRepWord64);
	r.CheckTypeError(kRepWord64, kRepWord32 \| kTypeInt32);
	r.CheckTypeError(kRepWord32 \| kTypeInt32, kRepWord64);
	r.CheckTypeError(kRepWord64, kRepWord32 \| kTypeUint32);
	r.CheckTypeError(kRepWord32 \| kTypeUint32, kRepWord64);

	for (size_t i = 0; i < arraysize(all_reps); i++) {
	for (size_t j = 0; j < arraysize(all_reps); j++) {
	if (i == j) continue;
	// Only a single from representation is allowed.
	r.CheckTypeError(all_reps[i] \| all_reps[j], kRepTagged);
	}
	}

	// TODO(titzer): Float32 representation changes trigger type errors now.
	// Enforce current behavior to test all paths through representation changer.
	for (size_t i = 0; i < arraysize(all_reps); i++) {
	r.CheckTypeError(all_reps[i], kRepFloat32);
	r.CheckTypeError(kRepFloat32, all_reps[i]);
	}
	}