NOINLINE string8 and stringUtf8

If they inline too early, our RULEs may be ineffective.  Better
performance was observed with `INLINE [0]` than `INLINE [1]`,
but `NOINLINE` works at least as well.

Author: hs-viktor

Data/ByteString/Builder.hs

@@ -442,7 +442,7 @@ char8 :: Char -> Builder
 char8 = P.primFixed P.char8
 
 -- | Char8 encode a 'String'.
-{-# INLINE [1] string8 #-} -- phased to allow literal cstring rewrites
+{-# NOINLINE string8 #-}
 string8 :: String -> Builder
 string8 = P.primMapListFixed P.char8
 
@@ -471,7 +471,7 @@ charUtf8 = P.primBounded P.charUtf8
 --
 -- Note that 'stringUtf8' performs no codepoint validation and consequently may
 -- emit invalid UTF-8 if asked (e.g. single surrogates).
-{-# INLINE [1] stringUtf8 #-} -- phased to allow literal cstring rewrites
+{-# NOINLINE stringUtf8 #-}
 stringUtf8 :: String -> Builder
 stringUtf8 = P.primMapListBounded P.charUtf8
 

bench/BenchAll.hs

@@ -259,6 +259,10 @@ asclit, utflit :: Ptr Word8 -> Builder
 asclit str@(Ptr addr) = BI.ascLiteralCopy str (byteCountLiteral addr)
 utflit str@(Ptr addr) = BI.modUtf8LitCopy str (byteCountLiteral addr)
 
+ascStr, utfStr :: String
+ascStr = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+utfStr = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\0xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+
 main :: IO ()
 main = do
   defaultMain
@@ -273,6 +277,10 @@ main = do
         , benchB' "String"        () $ \() -> asclit (Ptr "hello world!"#)
         , benchB' "AsciiLit"      () $ \() -> asclit ascBuf
         , benchB' "Utf8Lit"       () $ \() -> utflit utfBuf
+        , benchB' "strLit"        () $ \() -> string8 ascStr
+        , benchB' "utfLit"        () $ \() -> stringUtf8 utfStr
+        , benchB' "strLitInline"  () $ \() -> string8 "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
+        , benchB' "utfLitInline"  () $ \() -> stringUtf8 "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\0XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
         ]
 
       , bgroup "Encoding wrappers"