[wasm] Int64 lowering for I64SExtend operations

Change-Id: I488b47a51ef79c97545576fcc7d58e9147deb664
Reviewed-on: https://chromium-review.googlesource.com/1067677Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53285}

src/compiler/int64-lowering.cc

@@ -591,6 +591,7 @@ void Int64Lowering::LowerNode(Node* node) {
                       machine()->Uint32LessThanOrEqual());
       break;
     }
+    case IrOpcode::kSignExtendWord32ToInt64:
     case IrOpcode::kChangeInt32ToInt64: {
       DCHECK_EQ(1, node->InputCount());
       Node* input = node->InputAt(0);
@@ -860,6 +861,40 @@ void Int64Lowering::LowerNode(Node* node) {
                                    GetReplacementLow(input)));
       break;
     }
+    case IrOpcode::kSignExtendWord8ToInt64: {
+      DCHECK_EQ(1, node->InputCount());
+      Node* input = node->InputAt(0);
+      if (HasReplacementLow(input)) {
+        input = GetReplacementLow(input);
+      }
+      // Sign extend low node to Int32
+      input = graph()->NewNode(machine()->SignExtendWord8ToInt32(), input);
+
+      // We use SAR to preserve the sign in the high word.
+      ReplaceNode(
+          node, input,
+          graph()->NewNode(machine()->Word32Sar(), input,
+                           graph()->NewNode(common()->Int32Constant(31))));
+      node->NullAllInputs();
+      break;
+    }
+    case IrOpcode::kSignExtendWord16ToInt64: {
+      DCHECK_EQ(1, node->InputCount());
+      Node* input = node->InputAt(0);
+      if (HasReplacementLow(input)) {
+        input = GetReplacementLow(input);
+      }
+      // Sign extend low node to Int32
+      input = graph()->NewNode(machine()->SignExtendWord16ToInt32(), input);
+
+      // We use SAR to preserve the sign in the high word.
+      ReplaceNode(
+          node, input,
+          graph()->NewNode(machine()->Word32Sar(), input,
+                           graph()->NewNode(common()->Int32Constant(31))));
+      node->NullAllInputs();
+      break;
+    }
 
     default: { DefaultLowering(node); }
   }

test/cctest/wasm/test-run-wasm-sign-extension.cc

@@ -10,6 +10,7 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
+// TODO(gdeepti): Enable tests to run in the interpreter.
 WASM_COMPILED_EXEC_TEST(I32SExtendI8) {
   EXPERIMENTAL_FLAG_SCOPE(se);
   WasmRunner<int32_t, int32_t> r(execution_mode);
@@ -31,10 +32,7 @@ WASM_COMPILED_EXEC_TEST(I32SExtendI16) {
   CHECK_EQ(0x7afa, r.Call(0x7afa));
   CHECK_EQ(-0x8000, r.Call(0x8000));
 }
-// TODO(gdeepti): Enable tests to run in the interpreter, and on 32 bit
-// platforms after int64 lowering support. Add JS tests once all ops can be run
-// on 32 bit platforms.
-#if V8_TARGET_ARCH_64_BIT
+
 WASM_COMPILED_EXEC_TEST(I64SExtendI8) {
   EXPERIMENTAL_FLAG_SCOPE(se);
   WasmRunner<int64_t, int64_t> r(execution_mode);
@@ -67,7 +65,6 @@ WASM_COMPILED_EXEC_TEST(I64SExtendI32) {
   CHECK_EQ(0x7fffffff, r.Call(0x7fffffff));
   CHECK_EQ(-0x80000000LL, r.Call(0x80000000));
 }
-#endif  // V8_TARGET_ARCH_64_BIT
 
 }  // namespace wasm
 }  // namespace internal