[wasm] Fix codegen issue for i64.add and i64.sub on ia32

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/base/bits.h"
 #include "src/wasm/wasm-macro-gen.h"
@@ skipping 118 matching lines @@
 
 WASM_EXEC_TEST(I64Add) {
   REQUIRE(I64Add);
   WasmRunner<int64_t, int64_t, int64_t> r(execution_mode);
   BUILD(r, WASM_I64_ADD(WASM_GET_LOCAL(0), WASM_GET_LOCAL(1)));
   FOR_INT64_INPUTS(i) {
     FOR_INT64_INPUTS(j) { CHECK_EQ(*i + *j, r.Call(*i, *j)); }
   }
 }
 
+WASM_EXEC_TEST(I64AddRegress5800) {

[Mircea Trofin, 2017/01/18 21:01:56]

Elsewhere in cctest, we appear to have the naming pattern
"Regressxyz_somethingelse". 
Example (albeit this uses lower case rather than "Regress" like everywhere else)

./test-assembler-arm.cc:TEST(regress4292_b)

[Eric Holk, 2017/01/18 21:20:50]

Done.

+  REQUIRE(I64Add);
+  WasmRunner<int32_t> r(execution_mode);
+  BUILD(r, WASM_BLOCK(WASM_BR_IF(0, WASM_I64_EQZ(WASM_I64_ADD(
+                                        WASM_I64V(0), WASM_I64V(0x100000000)))),

[Mircea Trofin, 2017/01/18 21:01:56]

add comment explaining why you picked 0x100000000

maybe add a constant like kHasBit33On, and reuse in both tests.

[Eric Holk, 2017/01/18 21:20:50]

Done.

+                      WASM_RETURN1(WASM_I32V(0))),
+        WASM_I32V(0));
+  CHECK_EQ(0, r.Call());
+}
+
 WASM_EXEC_TEST(I64Sub) {
   REQUIRE(I64Sub);
   WasmRunner<int64_t, int64_t, int64_t> r(execution_mode);
   BUILD(r, WASM_I64_SUB(WASM_GET_LOCAL(0), WASM_GET_LOCAL(1)));
   FOR_INT64_INPUTS(i) {
     FOR_INT64_INPUTS(j) { CHECK_EQ(*i - *j, r.Call(*i, *j)); }
   }
 }
 
+WASM_EXEC_TEST(I64SubRegress5800) {
+  REQUIRE(I64Add);
+  WasmRunner<int32_t> r(execution_mode);
+  BUILD(r, WASM_BLOCK(WASM_BR_IF(0, WASM_I64_EQZ(WASM_I64_SUB(
+                                        WASM_I64V(0), WASM_I64V(0x100000000)))),
+                      WASM_RETURN1(WASM_I32V(0))),
+        WASM_I32V(0));
+  CHECK_EQ(0, r.Call());
+}
+
 WASM_EXEC_TEST(I64AddUseOnlyLowWord) {
   REQUIRE(I64Add);
   REQUIRE(I32ConvertI64);
   WasmRunner<int32_t, int64_t, int64_t> r(execution_mode);
   BUILD(r, WASM_I32_CONVERT_I64(
                WASM_I64_ADD(WASM_GET_LOCAL(0), WASM_GET_LOCAL(1))));
   FOR_INT64_INPUTS(i) {
     FOR_INT64_INPUTS(j) {
       CHECK_EQ(static_cast<int32_t>(*i + *j), r.Call(*i, *j));
     }
@@ skipping 1432 matching lines @@
         CHECK_EQ(expected, result);
       }
     }
   }
 }
 
 WASM_EXEC_TEST(MixedCall_i64_0) { Run_WasmMixedCall_N(execution_mode, 0); }
 WASM_EXEC_TEST(MixedCall_i64_1) { Run_WasmMixedCall_N(execution_mode, 1); }
 WASM_EXEC_TEST(MixedCall_i64_2) { Run_WasmMixedCall_N(execution_mode, 2); }
 WASM_EXEC_TEST(MixedCall_i64_3) { Run_WasmMixedCall_N(execution_mode, 3); }