[cleanup] Minor cleanup in boxed-float.h

The Float32(uint32_t) constructor should not be public, use
Float32::FromBits explicitly if needed.

R=ahaas@chromium.org

Change-Id: I414e621deebde8cdb474f17e08fcc489dbc083cd
Reviewed-on: https://chromium-review.googlesource.com/738173Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48934}

src/boxed-float.h

@@ -18,12 +18,7 @@ namespace internal {
 // the exact bit pattern during deoptimization when passing this value.
 class Float32 {
  public:
-  Float32() : bit_pattern_(0) {}
-
-  Float32(const Float32&) = default;
-
-  explicit constexpr Float32(uint32_t bit_pattern)
-      : bit_pattern_(bit_pattern) {}
+  Float32() = default;
 
   // This constructor does not guarantee that bit pattern of the input value
   // is preserved if the input is a NaN.
@@ -50,7 +45,10 @@ class Float32 {
   static constexpr Float32 FromBits(uint32_t bits) { return Float32(bits); }
 
  private:
-  uint32_t bit_pattern_;
+  uint32_t bit_pattern_ = 0;
+
+  explicit constexpr Float32(uint32_t bit_pattern)
+      : bit_pattern_(bit_pattern) {}
 };
 
 static_assert(IS_TRIVIALLY_COPYABLE(Float32),
@@ -62,9 +60,7 @@ static_assert(IS_TRIVIALLY_COPYABLE(Float32),
 // TODO(ahaas): Unify this class with Double in double.h
 class Float64 {
  public:
-  Float64() : bit_pattern_(0) {}
-
-  Float64(const Float64&) = default;
+  Float64() = default;
 
   // This constructor does not guarantee that bit pattern of the input value
   // is preserved if the input is a NaN.
@@ -90,9 +86,10 @@ class Float64 {
   static constexpr Float64 FromBits(uint64_t bits) { return Float64(bits); }
 
  private:
+  uint64_t bit_pattern_ = 0;
+
   explicit constexpr Float64(uint64_t bit_pattern)
       : bit_pattern_(bit_pattern) {}
-  uint64_t bit_pattern_;
 };
 
 static_assert(IS_TRIVIALLY_COPYABLE(Float64),

src/compiler/arm/code-generator-arm.cc

@@ -2426,7 +2426,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
         // Ensure byte indices are in [0, 31] so masks are never NaNs.
         four_lanes &= 0x1F1F1F1F;
         __ vmov(SwVfpRegister::from_code(scratch_s_base + j),
-                Float32(four_lanes));
+                Float32::FromBits(four_lanes));
       }
       NeonListOperand table(table_base, table_size);
       if (dst != src0 && dst != src1) {
@@ -3025,7 +3025,7 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
         __ str(temp, dst);
       } else {
         SwVfpRegister dst = g.ToFloatRegister(destination);
-        __ vmov(dst, Float32(src.ToFloat32AsInt()));
+        __ vmov(dst, Float32::FromBits(src.ToFloat32AsInt()));
       }
     } else {
       DCHECK_EQ(Constant::kFloat64, src.type());