[wasm] Do not produce code for br_if if its condition does not validate.

src/wasm/ast-decoder.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 "src/signature.h"
 
 #include "src/bit-vector.h"
 #include "src/flags.h"
 #include "src/handles.h"
 #include "src/zone-containers.h"
@@ skipping 1005 matching lines @@
             }
             len = 1 + operand.length;
             Push(kAstEnd, nullptr);
             break;
           }
           case kExprBrIf: {
             BreakDepthOperand operand(this, pc_);
             Value cond = Pop(operand.arity, kAstI32);
             Value val = {pc_, nullptr, kAstStmt};
             if (operand.arity == 1) val = Pop();
-            if (Validate(pc_, operand, control_)) {
+            if (ok() && Validate(pc_, operand, control_)) {
               SsaEnv* fenv = ssa_env_;
               SsaEnv* tenv = Split(fenv);
               fenv->SetNotMerged();
               BUILD(Branch, cond.node, &tenv->control, &fenv->control);
               ssa_env_ = tenv;
               BreakTo(operand, val);
               ssa_env_ = fenv;
             }
             len = 1 + operand.length;
             Push(kAstStmt, nullptr);
@@ skipping 1037 matching lines @@
 BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals,
                                            const byte* start, const byte* end) {
   FunctionBody body = {nullptr, nullptr, nullptr, start, end};
   WasmFullDecoder decoder(zone, nullptr, body);
   return decoder.AnalyzeLoopAssignmentForTesting(start, num_locals);
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8