[asmjs] Do constant folding for I32Asmjs(Div|Rem)S to avoid checks of constant divisors

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

Index: test/cctest/wasm/test-run-wasm.cc
diff --git a/test/cctest/wasm/test-run-wasm.cc b/test/cctest/wasm/test-run-wasm.cc
index a87656f408d8ba980810870dd29afa5286fb5f27..3b491d8bf821d9cacadf5e90f9989681dbd9abf1 100644
--- a/test/cctest/wasm/test-run-wasm.cc
+++ b/test/cctest/wasm/test-run-wasm.cc
@@ -448,6 +448,42 @@ WASM_EXEC_TEST(Int32DivS_byzero_const) {
   }
 }
 
+WASM_EXEC_TEST(Int32AsmjsDivS_byzero_const) {
+  for (int8_t denom = -2; denom < 8; ++denom) {
+    TestingModule module(execution_mode);
+    module.ChangeOriginToAsmjs();
+    WasmRunner<int32_t> r(&module, MachineType::Int32());
+    BUILD(r, WASM_I32_ASMJS_DIVS(WASM_GET_LOCAL(0), WASM_I8(denom)));
+    FOR_INT32_INPUTS(i) {
+      if (denom == 0) {
+        CHECK_EQ(0, r.Call(*i));
+      } else if (denom == -1 && *i == std::numeric_limits<int32_t>::min()) {
+        CHECK_EQ(std::numeric_limits<int32_t>::min(), r.Call(*i));
+      } else {
+        CHECK_EQ(*i / denom, r.Call(*i));
+      }
+    }
+  }
+}
+
+WASM_EXEC_TEST(Int32AsmjsRemS_byzero_const) {
+  for (int8_t denom = -2; denom < 8; ++denom) {
+    TestingModule module(execution_mode);
+    module.ChangeOriginToAsmjs();
+    WasmRunner<int32_t> r(&module, MachineType::Int32());
+    BUILD(r, WASM_I32_ASMJS_REMS(WASM_GET_LOCAL(0), WASM_I8(denom)));
+    FOR_INT32_INPUTS(i) {
+      if (denom == 0) {
+        CHECK_EQ(0, r.Call(*i));
+      } else if (denom == -1 && *i == std::numeric_limits<int32_t>::min()) {
+        CHECK_EQ(0, r.Call(*i));
+      } else {
+        CHECK_EQ(*i % denom, r.Call(*i));
+      }
+    }
+  }
+}
+
 WASM_EXEC_TEST(Int32DivU_byzero_const) {
   for (uint32_t denom = 0xfffffffe; denom < 8; ++denom) {
     WasmRunner<uint32_t> r(execution_mode, MachineType::Uint32());