[wasm] New attempt to implement the Int64Lowering of phis.

test/cctest/wasm/test-run-wasm-64.cc

 // Copyright 2015 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 <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "src/wasm/wasm-macro-gen.h"
 
@@ skipping 23 matching lines @@
 #endif
 
 #if V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_X87 || V8_TARGET_ARCH_ARM
 #define MIPS_OR_ARM_OR_X87 true
 #else
 #define MIPS_OR_ARM_OR_X87 false
 #endif
 
 #define FOREACH_I64_OPERATOR(V) \
   V(DepthFirst, true)           \
-  V(I64Phi, false)              \
+  V(I64Phi, true)               \
   V(I64Const, true)             \
   V(I64Return, true)            \
   V(I64Param, true)             \
   V(I64LoadStore, true)         \
   V(I64Add, !MIPS_OR_X87)       \
   V(I64Sub, !MIPS_OR_X87)       \
   V(I64Mul, false)              \
   V(I64DivS, true)              \
   V(I64DivU, true)              \
   V(I64RemS, true)              \
@@ skipping 1253 matching lines @@
   REQUIRE(I64Eq);
 
   WasmRunner<int32_t> r(MachineType::Int64());
   BUILD(r, WASM_I64_EQZ(WASM_GET_LOCAL(0)));
 
   FOR_INT64_INPUTS(i) {
     int32_t result = *i == 0 ? 1 : 0;
     CHECK_EQ(result, r.Call(*i));
   }
 }