Convert float64 to float32 when coerced with a heapf32 assignment.

test/cctest/test-asm-validator.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/v8.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/ast-expression-visitor.h"
 #include "src/ast/scopes.h"
 #include "src/parsing/parser.h"
@@ skipping 2330 matching lines @@
       }
       // return { testFunc1: test1, testFunc2: test2 };
       CHECK_EXPR(ObjectLiteral, Bounds::Unbounded()) {
         CHECK_VAR(test1, FUNC_I_TYPE);
         CHECK_VAR(test2, FUNC_D_TYPE);
       }
     }
   }
   CHECK_TYPES_END
 }
+
+TEST(StoreFloatFromDouble) {
+  CHECK_FUNC_TYPES_BEGIN(
+      "function bar() { f32[0] = 0.0; }\n"
+      "function foo() { bar(); }") {
+    CHECK_EXPR(FunctionLiteral, FUNC_V_TYPE) {
+      CHECK_EXPR(Assignment, Bounds(cache.kAsmDouble)) {
+        CHECK_EXPR(Property, Bounds::Unbounded()) {
+          CHECK_VAR(f32, Bounds(cache.kFloat32Array));
+          CHECK_EXPR(Literal, Bounds(cache.kAsmFixnum));
+        }
+        CHECK_EXPR(Literal, Bounds(cache.kAsmDouble));
+      }
+    }
+    CHECK_SKIP();
+  }
+  CHECK_FUNC_TYPES_END
+}