[turbofan] Remove Float32 truncation.

src/compiler/representation-change.h

Index: src/compiler/representation-change.h
diff --git a/src/compiler/representation-change.h b/src/compiler/representation-change.h
index fc2cc15affda74459137c55e36254c62f34a2439..8950b53f685179a3fb3aeec18617a772f82a392b 100644
--- a/src/compiler/representation-change.h
+++ b/src/compiler/representation-change.h
@@ -19,7 +19,6 @@ class Truncation final {
   static Truncation Bool() { return Truncation(TruncationKind::kBool); }
   static Truncation Word32() { return Truncation(TruncationKind::kWord32); }
   static Truncation Word64() { return Truncation(TruncationKind::kWord64); }
-  static Truncation Float32() { return Truncation(TruncationKind::kFloat32); }
   static Truncation Float64() { return Truncation(TruncationKind::kFloat64); }
   static Truncation Any() { return Truncation(TruncationKind::kAny); }
 
@@ -63,7 +62,6 @@ class Truncation final {
     kBool,
     kWord32,
     kWord64,
-    kFloat32,
     kFloat64,
     kAny
   };
@@ -134,8 +132,8 @@ class UseInfo {
   static UseInfo Bool() {
     return UseInfo(MachineRepresentation::kBit, Truncation::Bool());
   }
-  static UseInfo TruncatingFloat32() {
-    return UseInfo(MachineRepresentation::kFloat32, Truncation::Float32());
+  static UseInfo Float32() {
+    return UseInfo(MachineRepresentation::kFloat32, Truncation::Any());

[Jarin, 2016/10/12 18:04:01]

It might be better to say kFloat64; otherwise float32 use from of
float64-or-undefined value (such as read from a double or float typed array)
will force tagged representation.

[mvstanton, 2016/10/13 13:25:48]

Per our offline discussion, I'll go ahead and land it like this. Looks like
asm.js depends on this behavior.

   }
   static UseInfo TruncatingFloat64() {
     return UseInfo(MachineRepresentation::kFloat64, Truncation::Float64());