[wasm] Remove x / -1 = -x constant folding for wasm

test/mjsunit/wasm/float-constant-folding.js

 // Copyright 2017 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.
 
 // Flags: --expose-wasm
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 (function() {
@@ skipping 166 matching lines @@
       kExprI64Const, 32,
       kExprI64ShrU,
       kExprI32ConvertI64,
             ])
             .exportFunc();
   var module = builder.instantiate();
   assertEquals(0x7ffa0000, module.exports.F64Div1());
 })();
 
 (function() {
+  print("F64: sNaN / -1 = qNaN");
+  var builder = new WasmModuleBuilder();
+  builder.addFunction("F64Div1", kSig_i_i)
+    .addBody([
+      kExprI64Const, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0xf9, 0xff, 0x00,
+      kExprF64ReinterpretI64,

[titzer, 2017/01/31 17:24:49]

Can't this just be a F64Const?

[ahaas, 2017/01/31 19:43:37]

Actually no, for two reasons:
1) Other constant folding would apply, not the one I want to test.
2) There is no way to specify a signalling NaN in JavaScript.

+      kExprF64Const, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0xbf,
+      kExprF64Div,
+      kExprI64ReinterpretF64,
+      kExprI64Const, 32,
+      kExprI64ShrU,
+      kExprI32ConvertI64,
+            ])
+            .exportFunc();
+  var module = builder.instantiate();
+  assertEquals(0x7ffa0000, module.exports.F64Div1());
+})();
+
+(function() {
   print("F64: X / sNaN = qNaN");
   var builder = new WasmModuleBuilder();
   builder.addFunction("F64XDivNaN", kSig_i_i)
     .addBody([
       kExprF64Const, 0xde, 0xbc, 0x0a, 0x89, 0x67, 0x45, 0x23, 0x01,
       kExprF64Const, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf2, 0x7f,
       kExprF64Div,
       kExprI64ReinterpretF64,
       kExprI64Const, 32,
       kExprI64ShrU,
@@ skipping 14 matching lines @@
       kExprF64Div,
       kExprI64ReinterpretF64,
       kExprI64Const, 32,
       kExprI64ShrU,
       kExprI32ConvertI64,
             ])
             .exportFunc();
   var module = builder.instantiate();
   assertEquals(0x7ffa0000, module.exports.F64NaNDivX());
 })();