[arm64] The ubfx instruction can be used with a mask-width=64

The code-generator used i.InputInt6 to get the mask-width from the
instruction. However, thereby 64 got wrapped to 0, which is an invalid
mask width. I changed the i.InputInt6 to an i.InputInt32, which should
be okay because the mask-width comes from base::bits::CountPopulation64.

BUG=v8:6122
R=bmeurer@chromium.org, v8-arm-ports@googlegroups.com

Review-Url: https://codereview.chromium.org/2755373002
Cr-Commit-Position: refs/heads/master@{#43927}

src/compiler/arm64/code-generator-arm64.cc

@@ -1191,11 +1191,11 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       break;
     case kArm64Ubfx:
       __ Ubfx(i.OutputRegister(), i.InputRegister(0), i.InputInt6(1),
-              i.InputInt6(2));
+              i.InputInt32(2));
       break;
     case kArm64Ubfx32:
       __ Ubfx(i.OutputRegister32(), i.InputRegister32(0), i.InputInt5(1),
-              i.InputInt5(2));
+              i.InputInt32(2));
       break;
     case kArm64Ubfiz32:
       __ Ubfiz(i.OutputRegister32(), i.InputRegister32(0), i.InputInt5(1),

test/cctest/compiler/test-run-machops.cc

@@ -6746,6 +6746,15 @@ TEST(Regression6046a) {
   CHECK_EQ(0, m.Call());
 }
 
+TEST(Regression6122) {
+  BufferedRawMachineAssemblerTester<int64_t> m;
+  m.Return(m.Word64Shr(m.Word64And(m.Int64Constant(59), m.Int64Constant(-1)),
+                       m.Int64Constant(0)));
+  CHECK_EQ(59, m.Call());
+}
+
+#endif  // V8_TARGET_ARCH_64_BIT
+
 TEST(Regression6046b) {
   BufferedRawMachineAssemblerTester<int32_t> m;
   m.Return(m.Word32Shr(m.Word32And(m.Int32Constant(0), m.Int32Constant(0)),
@@ -6753,7 +6762,12 @@ TEST(Regression6046b) {
   CHECK_EQ(0, m.Call());
 }
 
-#endif  // V8_TARGET_ARCH_64_BIT
+TEST(Regression6122b) {
+  BufferedRawMachineAssemblerTester<int32_t> m;
+  m.Return(m.Word32Shr(m.Word32And(m.Int32Constant(59), m.Int32Constant(-1)),
+                       m.Int32Constant(0)));
+  CHECK_EQ(59, m.Call());
+}
 
 TEST(Regression6028) {
   BufferedRawMachineAssemblerTester<int32_t> m;