[wasm] Fix I32ReinterpretF32 and I64ReinterpretF64 on ia32.

src/wasm/wasm-interpreter.cc

 // Copyright 2016 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 "src/wasm/wasm-interpreter.h"
 
 #include "src/utils.h"
 #include "src/wasm/decoder.h"
 #include "src/wasm/function-body-decoder.h"
 #include "src/wasm/wasm-external-refs.h"
@@ skipping 141 matching lines @@
   V(F32SConvertI64, int64_t)     \
   V(F32UConvertI64, uint64_t)    \
   V(F32ConvertF64, double)       \
   V(F32ReinterpretI32, int32_t)  \
   V(F64SConvertI32, int32_t)     \
   V(F64UConvertI32, uint32_t)    \
   V(F64SConvertI64, int64_t)     \
   V(F64UConvertI64, uint64_t)    \
   V(F64ConvertF32, float)        \
   V(F64ReinterpretI64, int64_t)  \
-  V(I32ReinterpretF32, float)    \
-  V(I64ReinterpretF64, double)   \
   V(I32AsmjsSConvertF32, float)  \
   V(I32AsmjsUConvertF32, float)  \
   V(I32AsmjsSConvertF64, double) \
   V(I32AsmjsUConvertF64, double)
 
 #define FOREACH_OTHER_UNOP_NAN(V) \
   V(F32Sqrt, float)               \
   V(F64Sqrt, double)
 
 static inline int32_t ExecuteI32DivS(int32_t a, int32_t b, TrapReason* trap) {
@@ skipping 425 matching lines @@
 }
 
 static inline double ExecuteF64ConvertF32(float a, TrapReason* trap) {
   return static_cast<double>(a);
 }
 
 static inline double ExecuteF64ReinterpretI64(int64_t a, TrapReason* trap) {
   return bit_cast<double>(a);
 }
 
-static inline int32_t ExecuteI32ReinterpretF32(float a, TrapReason* trap) {
-  return bit_cast<int32_t>(a);
+static inline int32_t ExecuteI32ReinterpretF32(WasmVal a) {
+  return a.to_unchecked<int32_t>();
 }
 
-static inline int64_t ExecuteI64ReinterpretF64(double a, TrapReason* trap) {
-  return bit_cast<int64_t>(a);
+static inline int64_t ExecuteI64ReinterpretF64(WasmVal a) {
+  return a.to_unchecked<int64_t>();
 }
 
 static inline int32_t ExecuteGrowMemory(uint32_t delta_pages,
                                         WasmInstance* instance) {
   // TODO(ahaas): Move memory allocation to wasm-module.cc for better
   // encapsulation.
   if (delta_pages > wasm::kV8MaxWasmMemoryPages ||
       delta_pages > instance->module->max_mem_pages) {
     return -1;
   }
@@ skipping 922 matching lines @@
           len = 1 + operand.length;
           break;
         }
         case kExprMemorySize: {
           MemoryIndexOperand operand(&decoder, code->at(pc));
           Push(pc, WasmVal(static_cast<uint32_t>(instance()->mem_size /
                                                  WasmModule::kPageSize)));
           len = 1 + operand.length;
           break;
         }
+        // We handle kExprI32ReinterpretF32 and kExprI64ReinterpretF64 specially
+        // because on ia32 we may loose the signalling bit of NaNs otherwise.

[Clemens Hammacher, 2017/01/18 18:03:49]

lose, not loose. I would also write signaling instead of signalling (there are
more occurences).

[ahaas, 2017/01/18 18:13:49]

I rewrote the comment.

+        case kExprI32ReinterpretF32: {
+          WasmVal result(ExecuteI32ReinterpretF32(Pop()));
+          Push(pc, result);
+          break;
+        }
+        case kExprI64ReinterpretF64: {
+          WasmVal result(ExecuteI64ReinterpretF64(Pop()));
+          Push(pc, result);
+          break;
+        }
 #define EXECUTE_SIMPLE_BINOP(name, ctype, op)             \
   case kExpr##name: {                                     \
     WasmVal rval = Pop();                                 \
     WasmVal lval = Pop();                                 \
     WasmVal result(lval.to<ctype>() op rval.to<ctype>()); \
     Push(pc, result);                                     \
     break;                                                \
   }
           FOREACH_SIMPLE_BINOP(EXECUTE_SIMPLE_BINOP)
 #undef EXECUTE_SIMPLE_BINOP
@@ skipping 272 matching lines @@
 
 ControlTransferMap WasmInterpreter::ComputeControlTransfersForTesting(
     Zone* zone, const byte* start, const byte* end) {
   ControlTransfers targets(zone, nullptr, start, end);
   return targets.map_;
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8