Revert of [x64] Improve instruction selection for TruncateInt64ToInt32. (patchset...

Reason for revert:
Breaks SQLite

Original issue's description:
> [x64] Improve instruction selection for TruncateInt64ToInt32.
>
> R=svenpanne@chromium.org
>
> Committed: https://crrev.com/64a2717529e2197f3a789adabf86ca36f5eb764c
> Cr-Commit-Position: refs/heads/master@{#26739}

TBR=svenpanne@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/928723003

Cr-Commit-Position: refs/heads/master@{#26791}

diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index 48c6d80664b546842d31ff0340c4b855c015ed29..c1328b3ee30683f9c1324e5eec8abe3d59c3d646 100644 (file)
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -812,22 +812,12 @@ void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
   Node* value = node->InputAt(0);
   if (CanCover(node, value)) {
     switch (value->opcode()) {
-      case IrOpcode::kWord64Sar: {
+      case IrOpcode::kWord64Sar:
+      case IrOpcode::kWord64Shr: {
         Int64BinopMatcher m(value);
-        if (m.right().IsInRange(1, 32)) {
+        if (m.right().Is(32)) {
           Emit(kX64Shr, g.DefineSameAsFirst(node),
-               g.UseRegister(m.left().node()),
-               g.UseImmediate(m.right().node()));
-          return;
-        }
-        break;
-      }
-      case IrOpcode::kWord64Shl: {
-        Int64BinopMatcher m(value);
-        if (m.right().IsInRange(1, 31)) {
-          Emit(kX64Shl32, g.DefineSameAsFirst(node),
-               g.UseRegister(m.left().node()),
-               g.UseImmediate(m.right().node()));
+               g.UseRegister(m.left().node()), g.TempImmediate(32));
           return;
         }
         break;
@@ -836,9 +826,7 @@ void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
         break;
     }
   }
-  // Otherwise truncation from 64-bit to 32-bit is a no-nop, as 32-bit
-  // operations just ignore the upper 64-bit.
-  Emit(kArchNop, g.DefineAsRegister(node), g.Use(value));
+  Emit(kX64Movl, g.DefineAsRegister(node), g.Use(value));
 }
 
 

diff --git a/test/unittests/compiler/x64/instruction-selector-x64-unittest.cc b/test/unittests/compiler/x64/instruction-selector-x64-unittest.cc
index e524764f828626c4d1459e2857c3b450d1987f7f..1f374c0f856d7662cbcda5812bf556a10696ab73 100644 (file)
--- a/test/unittests/compiler/x64/instruction-selector-x64-unittest.cc
+++ b/test/unittests/compiler/x64/instruction-selector-x64-unittest.cc
@@ -63,6 +63,15 @@ TEST_F(InstructionSelectorTest, TruncateFloat64ToFloat32WithParameter) {
 }
 
 
+TEST_F(InstructionSelectorTest, TruncateInt64ToInt32WithParameter) {
+  StreamBuilder m(this, kMachInt32, kMachInt64);
+  m.Return(m.TruncateInt64ToInt32(m.Parameter(0)));
+  Stream s = m.Build();
+  ASSERT_EQ(1U, s.size());
+  EXPECT_EQ(kX64Movl, s[0]->arch_opcode());
+}
+
+
 // -----------------------------------------------------------------------------
 // Loads and stores
 
@@ -197,49 +206,37 @@ INSTANTIATE_TEST_CASE_P(InstructionSelectorTest,
 // TruncateInt64ToInt32.
 
 
-TEST_F(InstructionSelectorTest, TruncateInt64ToInt32WithParameter) {
+TEST_F(InstructionSelectorTest, TruncateInt64ToInt32WithWord64Sar) {
   StreamBuilder m(this, kMachInt32, kMachInt64);
-  m.Return(m.TruncateInt64ToInt32(m.Parameter(0)));
+  Node* const p = m.Parameter(0);
+  Node* const t = m.TruncateInt64ToInt32(m.Word64Sar(p, m.Int64Constant(32)));
+  m.Return(t);
   Stream s = m.Build();
-  ASSERT_EQ(0U, s.size());
-}
-
-
-TEST_F(InstructionSelectorTest, TruncateInt64ToInt32WithWord64Sar) {
-  TRACED_FORRANGE(int32_t, k, 1, 32) {
-    StreamBuilder m(this, kMachInt32, kMachInt64);
-    Node* const p = m.Parameter(0);
-    Node* const t = m.TruncateInt64ToInt32(m.Word64Sar(p, m.Int64Constant(k)));
-    m.Return(t);
-    Stream s = m.Build();
-    ASSERT_EQ(1U, s.size());
-    EXPECT_EQ(kX64Shr, s[0]->arch_opcode());
-    ASSERT_EQ(2U, s[0]->InputCount());
-    EXPECT_EQ(s.ToVreg(p), s.ToVreg(s[0]->InputAt(0)));
-    EXPECT_EQ(k, s.ToInt32(s[0]->InputAt(1)));
-    ASSERT_EQ(1U, s[0]->OutputCount());
-    EXPECT_TRUE(s.IsSameAsFirst(s[0]->OutputAt(0)));
-    EXPECT_EQ(s.ToVreg(t), s.ToVreg(s[0]->OutputAt(0)));
-  }
+  ASSERT_EQ(1U, s.size());
+  EXPECT_EQ(kX64Shr, s[0]->arch_opcode());
+  ASSERT_EQ(2U, s[0]->InputCount());
+  EXPECT_EQ(s.ToVreg(p), s.ToVreg(s[0]->InputAt(0)));
+  EXPECT_EQ(32, s.ToInt32(s[0]->InputAt(1)));
+  ASSERT_EQ(1U, s[0]->OutputCount());
+  EXPECT_TRUE(s.IsSameAsFirst(s[0]->OutputAt(0)));
+  EXPECT_EQ(s.ToVreg(t), s.ToVreg(s[0]->OutputAt(0)));
 }
 
 
-TEST_F(InstructionSelectorTest, TruncateInt64ToInt32WithWord64Shl) {
-  TRACED_FORRANGE(int32_t, k, 1, 31) {
-    StreamBuilder m(this, kMachInt32, kMachInt64);
-    Node* const p = m.Parameter(0);
-    Node* const t = m.TruncateInt64ToInt32(m.Word64Shl(p, m.Int64Constant(k)));
-    m.Return(t);
-    Stream s = m.Build();
-    ASSERT_EQ(1U, s.size());
-    EXPECT_EQ(kX64Shl32, s[0]->arch_opcode());
-    ASSERT_EQ(2U, s[0]->InputCount());
-    EXPECT_EQ(s.ToVreg(p), s.ToVreg(s[0]->InputAt(0)));
-    EXPECT_EQ(k, s.ToInt32(s[0]->InputAt(1)));
-    ASSERT_EQ(1U, s[0]->OutputCount());
-    EXPECT_TRUE(s.IsSameAsFirst(s[0]->OutputAt(0)));
-    EXPECT_EQ(s.ToVreg(t), s.ToVreg(s[0]->OutputAt(0)));
-  }
+TEST_F(InstructionSelectorTest, TruncateInt64ToInt32WithWord64Shr) {
+  StreamBuilder m(this, kMachInt32, kMachInt64);
+  Node* const p = m.Parameter(0);
+  Node* const t = m.TruncateInt64ToInt32(m.Word64Shr(p, m.Int64Constant(32)));
+  m.Return(t);
+  Stream s = m.Build();
+  ASSERT_EQ(1U, s.size());
+  EXPECT_EQ(kX64Shr, s[0]->arch_opcode());
+  ASSERT_EQ(2U, s[0]->InputCount());
+  EXPECT_EQ(s.ToVreg(p), s.ToVreg(s[0]->InputAt(0)));
+  EXPECT_EQ(32, s.ToInt32(s[0]->InputAt(1)));
+  ASSERT_EQ(1U, s[0]->OutputCount());
+  EXPECT_TRUE(s.IsSameAsFirst(s[0]->OutputAt(0)));
+  EXPECT_EQ(s.ToVreg(t), s.ToVreg(s[0]->OutputAt(0)));
 }