[compiler] Fix turbofan string allocation

src/code-stub-assembler.cc

Index: src/code-stub-assembler.cc
diff --git a/src/code-stub-assembler.cc b/src/code-stub-assembler.cc
index 34b480705c0fe2633d5c5fc5457b650ec4986e5d..5bb1e3d001756133b2e85d117e52613bf80e7a43 100644
--- a/src/code-stub-assembler.cc
+++ b/src/code-stub-assembler.cc
@@ -695,7 +695,8 @@ Node* CodeStubAssembler::AllocateSeqOneByteString(int length) {
   StoreObjectFieldNoWriteBarrier(result, SeqOneByteString::kLengthOffset,
                                  SmiConstant(Smi::FromInt(length)));
   StoreObjectFieldNoWriteBarrier(result, SeqOneByteString::kHashFieldOffset,
-                                 IntPtrConstant(String::kEmptyHashField));
+                                 IntPtrConstant(String::kEmptyHashField),
+                                 MachineRepresentation::kWord32);
   return result;
 }
 
@@ -722,7 +723,8 @@ Node* CodeStubAssembler::AllocateSeqOneByteString(Node* context, Node* length) {
     StoreObjectFieldNoWriteBarrier(result, SeqOneByteString::kLengthOffset,
                                    SmiFromWord(length));
     StoreObjectFieldNoWriteBarrier(result, SeqOneByteString::kHashFieldOffset,
-                                   IntPtrConstant(String::kEmptyHashField));
+                                   IntPtrConstant(String::kEmptyHashField),
+                                   MachineRepresentation::kWord32);
     var_result.Bind(result);
     Goto(&if_join);
   }
@@ -746,7 +748,8 @@ Node* CodeStubAssembler::AllocateSeqTwoByteString(int length) {
   StoreObjectFieldNoWriteBarrier(result, SeqTwoByteString::kLengthOffset,
                                  SmiConstant(Smi::FromInt(length)));
   StoreObjectFieldNoWriteBarrier(result, SeqTwoByteString::kHashFieldOffset,
-                                 IntPtrConstant(String::kEmptyHashField));
+                                 IntPtrConstant(String::kEmptyHashField),
+                                 MachineRepresentation::kWord32);
   return result;
 }
 
@@ -773,7 +776,8 @@ Node* CodeStubAssembler::AllocateSeqTwoByteString(Node* context, Node* length) {
     StoreObjectFieldNoWriteBarrier(result, SeqTwoByteString::kLengthOffset,
                                    SmiFromWord(length));
     StoreObjectFieldNoWriteBarrier(result, SeqTwoByteString::kHashFieldOffset,
-                                   IntPtrConstant(String::kEmptyHashField));
+                                   IntPtrConstant(String::kEmptyHashField),
+                                   MachineRepresentation::kWord32);
     var_result.Bind(result);
     Goto(&if_join);
   }