1 files changed, 299 insertions, 0 deletions
diff --git a/js/src/jsapi-tests/testJitGVN.cpp b/js/src/jsapi-tests/testJitGVN.cpp
new file mode 100644
index 0000000000..4dd8d64fde
--- /dev/null
+++ b/js/src/jsapi-tests/testJitGVN.cpp
@@ -0,0 +1,299 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "jit/IonAnalysis.h"
+#include "jit/MIRGenerator.h"
+#include "jit/MIRGraph.h"
+#include "jit/RangeAnalysis.h"
+#include "jit/ValueNumbering.h"
+
+#include "jsapi-tests/testJitMinimalFunc.h"
+#include "jsapi-tests/tests.h"
+
+using namespace js;
+using namespace js::jit;
+
+static MBasicBlock* FollowTrivialGotos(MBasicBlock* block) {
+  while (block->phisEmpty() && *block->begin() == block->lastIns() &&
+         block->lastIns()->isGoto()) {
+    block = block->lastIns()->toGoto()->getSuccessor(0);
+  }
+  return block;
+}
+
+BEGIN_TEST(testJitGVN_FixupOSROnlyLoop) {
+  // This is a testcase which constructs the very rare circumstances that
+  // require the FixupOSROnlyLoop logic.
+
+  MinimalFunc func;
+
+  MBasicBlock* entry = func.createEntryBlock();
+  MBasicBlock* osrEntry = func.createOsrEntryBlock();
+  MBasicBlock* outerHeader = func.createBlock(entry);
+  MBasicBlock* merge = func.createBlock(outerHeader);
+  MBasicBlock* innerHeader = func.createBlock(merge);
+  MBasicBlock* innerBackedge = func.createBlock(innerHeader);
+  MBasicBlock* outerBackedge = func.createBlock(innerHeader);
+  MBasicBlock* exit = func.createBlock(outerHeader);
+
+  MConstant* c = MConstant::New(func.alloc, BooleanValue(false));
+  entry->add(c);
+  entry->end(MTest::New(func.alloc, c, outerHeader, exit));
+  osrEntry->end(MGoto::New(func.alloc, merge));
+
+  merge->end(MGoto::New(func.alloc, innerHeader));
+
+  // Use Beta nodes to hide the constants and suppress folding.
+  MConstant* x = MConstant::New(func.alloc, BooleanValue(false));
+  outerHeader->add(x);
+  MBeta* xBeta =
+      MBeta::New(func.alloc, x, Range::NewInt32Range(func.alloc, 0, 1));
+  outerHeader->add(xBeta);
+  outerHeader->end(MTest::New(func.alloc, xBeta, merge, exit));
+
+  MConstant* y = MConstant::New(func.alloc, BooleanValue(false));
+  innerHeader->add(y);
+  MBeta* yBeta =
+      MBeta::New(func.alloc, y, Range::NewInt32Range(func.alloc, 0, 1));
+  innerHeader->add(yBeta);
+  innerHeader->end(MTest::New(func.alloc, yBeta, innerBackedge, outerBackedge));
+
+  innerBackedge->end(MGoto::New(func.alloc, innerHeader));
+  outerBackedge->end(MGoto::New(func.alloc, outerHeader));
+
+  MConstant* u = MConstant::New(func.alloc, UndefinedValue());
+  exit->add(u);
+  exit->end(MReturn::New(func.alloc, u));
+
+  MOZ_ALWAYS_TRUE(innerHeader->addPredecessorWithoutPhis(innerBackedge));
+  MOZ_ALWAYS_TRUE(outerHeader->addPredecessorWithoutPhis(outerBackedge));
+  MOZ_ALWAYS_TRUE(exit->addPredecessorWithoutPhis(entry));
+  MOZ_ALWAYS_TRUE(merge->addPredecessorWithoutPhis(osrEntry));
+
+  outerHeader->setLoopHeader(outerBackedge);
+  innerHeader->setLoopHeader(innerBackedge);
+
+  if (!func.runGVN()) {
+    return false;
+  }
+
+  // The loops are no longer reachable from the normal entry. They are
+  // doinated by the osrEntry.
+  MOZ_RELEASE_ASSERT(func.graph.osrBlock() == osrEntry);
+  MBasicBlock* newInner =
+      FollowTrivialGotos(osrEntry->lastIns()->toGoto()->target());
+  MBasicBlock* newOuter =
+      FollowTrivialGotos(newInner->lastIns()->toTest()->ifFalse());
+  MBasicBlock* newExit = FollowTrivialGotos(entry);
+  MOZ_RELEASE_ASSERT(newInner->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newOuter->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newExit->lastIns()->isReturn());
+
+  // One more time.
+  ClearDominatorTree(func.graph);
+  if (!func.runGVN()) {
+    return false;
+  }
+
+  // The loops are no longer reachable from the normal entry. They are
+  // doinated by the osrEntry.
+  MOZ_RELEASE_ASSERT(func.graph.osrBlock() == osrEntry);
+  newInner = FollowTrivialGotos(osrEntry->lastIns()->toGoto()->target());
+  newOuter = FollowTrivialGotos(newInner->lastIns()->toTest()->ifFalse());
+  newExit = FollowTrivialGotos(entry);
+  MOZ_RELEASE_ASSERT(newInner->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newOuter->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newExit->lastIns()->isReturn());
+
+  return true;
+}
+END_TEST(testJitGVN_FixupOSROnlyLoop)
+
+BEGIN_TEST(testJitGVN_FixupOSROnlyLoopNested) {
+  // Same as testJitGVN_FixupOSROnlyLoop but adds another level of loop
+  // nesting for added excitement.
+
+  MinimalFunc func;
+
+  MBasicBlock* entry = func.createEntryBlock();
+  MBasicBlock* osrEntry = func.createOsrEntryBlock();
+  MBasicBlock* outerHeader = func.createBlock(entry);
+  MBasicBlock* middleHeader = func.createBlock(outerHeader);
+  MBasicBlock* merge = func.createBlock(middleHeader);
+  MBasicBlock* innerHeader = func.createBlock(merge);
+  MBasicBlock* innerBackedge = func.createBlock(innerHeader);
+  MBasicBlock* middleBackedge = func.createBlock(innerHeader);
+  MBasicBlock* outerBackedge = func.createBlock(middleHeader);
+  MBasicBlock* exit = func.createBlock(outerHeader);
+
+  MConstant* c = MConstant::New(func.alloc, BooleanValue(false));
+  entry->add(c);
+  entry->end(MTest::New(func.alloc, c, outerHeader, exit));
+  osrEntry->end(MGoto::New(func.alloc, merge));
+
+  merge->end(MGoto::New(func.alloc, innerHeader));
+
+  // Use Beta nodes to hide the constants and suppress folding.
+  MConstant* x = MConstant::New(func.alloc, BooleanValue(false));
+  outerHeader->add(x);
+  MBeta* xBeta =
+      MBeta::New(func.alloc, x, Range::NewInt32Range(func.alloc, 0, 1));
+  outerHeader->add(xBeta);
+  outerHeader->end(MTest::New(func.alloc, xBeta, middleHeader, exit));
+
+  MConstant* y = MConstant::New(func.alloc, BooleanValue(false));
+  middleHeader->add(y);
+  MBeta* yBeta =
+      MBeta::New(func.alloc, y, Range::NewInt32Range(func.alloc, 0, 1));
+  middleHeader->add(yBeta);
+  middleHeader->end(MTest::New(func.alloc, yBeta, merge, outerBackedge));
+
+  MConstant* w = MConstant::New(func.alloc, BooleanValue(false));
+  innerHeader->add(w);
+  MBeta* wBeta =
+      MBeta::New(func.alloc, w, Range::NewInt32Range(func.alloc, 0, 1));
+  innerHeader->add(wBeta);
+  innerHeader->end(
+      MTest::New(func.alloc, wBeta, innerBackedge, middleBackedge));
+
+  innerBackedge->end(MGoto::New(func.alloc, innerHeader));
+  middleBackedge->end(MGoto::New(func.alloc, middleHeader));
+  outerBackedge->end(MGoto::New(func.alloc, outerHeader));
+
+  MConstant* u = MConstant::New(func.alloc, UndefinedValue());
+  exit->add(u);
+  exit->end(MReturn::New(func.alloc, u));
+
+  MOZ_ALWAYS_TRUE(innerHeader->addPredecessorWithoutPhis(innerBackedge));
+  MOZ_ALWAYS_TRUE(middleHeader->addPredecessorWithoutPhis(middleBackedge));
+  MOZ_ALWAYS_TRUE(outerHeader->addPredecessorWithoutPhis(outerBackedge));
+  MOZ_ALWAYS_TRUE(exit->addPredecessorWithoutPhis(entry));
+  MOZ_ALWAYS_TRUE(merge->addPredecessorWithoutPhis(osrEntry));
+
+  outerHeader->setLoopHeader(outerBackedge);
+  middleHeader->setLoopHeader(middleBackedge);
+  innerHeader->setLoopHeader(innerBackedge);
+
+  if (!func.runGVN()) {
+    return false;
+  }
+
+  // The loops are no longer reachable from the normal entry. They are
+  // doinated by the osrEntry.
+  MOZ_RELEASE_ASSERT(func.graph.osrBlock() == osrEntry);
+  MBasicBlock* newInner =
+      FollowTrivialGotos(osrEntry->lastIns()->toGoto()->target());
+  MBasicBlock* newMiddle =
+      FollowTrivialGotos(newInner->lastIns()->toTest()->ifFalse());
+  MBasicBlock* newOuter =
+      FollowTrivialGotos(newMiddle->lastIns()->toTest()->ifFalse());
+  MBasicBlock* newExit = FollowTrivialGotos(entry);
+  MOZ_RELEASE_ASSERT(newInner->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newMiddle->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newOuter->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newExit->lastIns()->isReturn());
+
+  // One more time.
+  ClearDominatorTree(func.graph);
+  if (!func.runGVN()) {
+    return false;
+  }
+
+  // The loops are no longer reachable from the normal entry. They are
+  // doinated by the osrEntry.
+  MOZ_RELEASE_ASSERT(func.graph.osrBlock() == osrEntry);
+  newInner = FollowTrivialGotos(osrEntry->lastIns()->toGoto()->target());
+  newMiddle = FollowTrivialGotos(newInner->lastIns()->toTest()->ifFalse());
+  newOuter = FollowTrivialGotos(newMiddle->lastIns()->toTest()->ifFalse());
+  newExit = FollowTrivialGotos(entry);
+  MOZ_RELEASE_ASSERT(newInner->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newMiddle->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newOuter->isLoopHeader());
+  MOZ_RELEASE_ASSERT(newExit->lastIns()->isReturn());
+
+  return true;
+}
+END_TEST(testJitGVN_FixupOSROnlyLoopNested)
+
+BEGIN_TEST(testJitGVN_PinnedPhis) {
+  // Set up a loop which gets optimized away, with phis which must be
+  // cleaned up, permitting more phis to be cleaned up.
+
+  MinimalFunc func;
+
+  MBasicBlock* entry = func.createEntryBlock();
+  MBasicBlock* outerHeader = func.createBlock(entry);
+  MBasicBlock* outerBlock = func.createBlock(outerHeader);
+  MBasicBlock* innerHeader = func.createBlock(outerBlock);
+  MBasicBlock* innerBackedge = func.createBlock(innerHeader);
+  MBasicBlock* exit = func.createBlock(innerHeader);
+
+  MPhi* phi0 = MPhi::New(func.alloc);
+  MPhi* phi1 = MPhi::New(func.alloc);
+  MPhi* phi2 = MPhi::New(func.alloc);
+  MPhi* phi3 = MPhi::New(func.alloc);
+
+  MParameter* p = func.createParameter();
+  entry->add(p);
+  MConstant* z0 = MConstant::New(func.alloc, Int32Value(0));
+  MConstant* z1 = MConstant::New(func.alloc, Int32Value(1));
+  MConstant* z2 = MConstant::New(func.alloc, Int32Value(2));
+  MConstant* z3 = MConstant::New(func.alloc, Int32Value(2));
+  MOZ_RELEASE_ASSERT(phi0->addInputSlow(z0));
+  MOZ_RELEASE_ASSERT(phi1->addInputSlow(z1));
+  MOZ_RELEASE_ASSERT(phi2->addInputSlow(z2));
+  MOZ_RELEASE_ASSERT(phi3->addInputSlow(z3));
+  entry->add(z0);
+  entry->add(z1);
+  entry->add(z2);
+  entry->add(z3);
+  entry->end(MGoto::New(func.alloc, outerHeader));
+
+  outerHeader->addPhi(phi0);
+  outerHeader->addPhi(phi1);
+  outerHeader->addPhi(phi2);
+  outerHeader->addPhi(phi3);
+  outerHeader->end(MGoto::New(func.alloc, outerBlock));
+
+  outerBlock->end(MGoto::New(func.alloc, innerHeader));
+
+  MConstant* true_ = MConstant::New(func.alloc, BooleanValue(true));
+  innerHeader->add(true_);
+  innerHeader->end(MTest::New(func.alloc, true_, innerBackedge, exit));
+
+  innerBackedge->end(MGoto::New(func.alloc, innerHeader));
+
+  MInstruction* z4 = MAdd::New(func.alloc, phi0, phi1, MIRType::Int32);
+  MConstant* z5 = MConstant::New(func.alloc, Int32Value(4));
+  MInstruction* z6 = MAdd::New(func.alloc, phi2, phi3, MIRType::Int32);
+  MConstant* z7 = MConstant::New(func.alloc, Int32Value(6));
+  MOZ_RELEASE_ASSERT(phi0->addInputSlow(z4));
+  MOZ_RELEASE_ASSERT(phi1->addInputSlow(z5));
+  MOZ_RELEASE_ASSERT(phi2->addInputSlow(z6));
+  MOZ_RELEASE_ASSERT(phi3->addInputSlow(z7));
+  exit->add(z4);
+  exit->add(z5);
+  exit->add(z6);
+  exit->add(z7);
+  exit->end(MGoto::New(func.alloc, outerHeader));
+
+  MOZ_ALWAYS_TRUE(innerHeader->addPredecessorWithoutPhis(innerBackedge));
+  MOZ_ALWAYS_TRUE(outerHeader->addPredecessorWithoutPhis(exit));
+
+  outerHeader->setLoopHeader(exit);
+  innerHeader->setLoopHeader(innerBackedge);
+
+  if (!func.runGVN()) {
+    return false;
+  }
+
+  MOZ_RELEASE_ASSERT(innerHeader->phisEmpty());
+  MOZ_RELEASE_ASSERT(exit->isDead());
+
+  return true;
+}
+END_TEST(testJitGVN_PinnedPhis)