sha512

commit 669c4ffd1cc7826876af2d67661738c2081ea6a9
parent ba7757cf61132cf3c3d79960f51ddaf4801f7aec
Author: Jared Tobin <jared@jtobin.io>
Date:   Mon, 22 Dec 2025 17:33:46 -0330

meta: add llvm flag

Diffstat:
M
README.md
 | 
28
+++++++---------------------
M
flake.nix
 | 
3
+++
M
ppad-sha512.cabal
 | 
7
+++++++

3 files changed, 17 insertions(+), 21 deletions(-)
diff --git a/README.md b/README.md
@@ -63,33 +63,19 @@ Current benchmark figures on an M4 Silicon MacBook Air look like (use
 
 ```
   benchmarking ppad-sha512/SHA512 (32B input)/hash
-  time                 957.1 ns   (956.3 ns .. 957.7 ns)
+  time                 419.3 ns   (419.1 ns .. 419.7 ns)
                        1.000 R²   (1.000 R² .. 1.000 R²)
-  mean                 956.1 ns   (955.6 ns .. 956.6 ns)
-  std dev              1.714 ns   (1.436 ns .. 2.174 ns)
+  mean                 420.4 ns   (420.1 ns .. 421.1 ns)
+  std dev              1.507 ns   (843.5 ps .. 2.705 ns)
 
   benchmarking ppad-sha512/HMAC-SHA512 (32B input)/hmac
-  time                 3.460 μs   (3.448 μs .. 3.475 μs)
+  time                 1.340 μs   (1.339 μs .. 1.341 μs)
                        1.000 R²   (1.000 R² .. 1.000 R²)
-  mean                 3.474 μs   (3.468 μs .. 3.478 μs)
-  std dev              16.60 ns   (11.71 ns .. 24.66 ns)
+  mean                 1.343 μs   (1.342 μs .. 1.347 μs)
+  std dev              8.443 ns   (3.955 ns .. 14.85 ns)
 ```
 
-Compare this to Hackage's venerable SHA package:
-
-```
-  benchmarking ppad-sha512/SHA512 (32B input)/SHA.sha512
-  time                 1.437 μs   (1.436 μs .. 1.437 μs)
-                       1.000 R²   (1.000 R² .. 1.000 R²)
-  mean                 1.440 μs   (1.435 μs .. 1.452 μs)
-  std dev              23.57 ns   (11.13 ns .. 43.08 ns)
-
-  benchmarking ppad-sha512/HMAC-SHA512 (32B input)/SHA.hmacSha512
-  time                 5.164 μs   (5.162 μs .. 5.166 μs)
-                       1.000 R²   (1.000 R² .. 1.000 R²)
-  mean                 5.159 μs   (5.157 μs .. 5.161 μs)
-  std dev              6.522 ns   (5.534 ns .. 7.662 ns)
-```
+You should compile with the 'llvm' flag for maximum performance.
 
 ## Security
 
diff --git a/flake.nix b/flake.nix
@@ -25,6 +25,7 @@
 
         pkgs = import nixpkgs { inherit system; };
         hlib = pkgs.haskell.lib;
+        llvm = pkgs.llvmPackages_15.llvm;
 
         base16 = ppad-base16.packages.${system}.default;
 
@@ -50,6 +51,7 @@
             buildInputs = [
               cabal
               cc
+              llvm
             ];
 
             inputsFrom = builtins.attrValues self.packages.${system};
@@ -62,6 +64,7 @@
               echo "cc:    $(${cc}/bin/cc --version)"
               echo "ghc:   $(${ghc}/bin/ghc --version)"
               echo "cabal: $(${cabal}/bin/cabal --version)"
+              echo "llc:   $(${llvm}/bin/llc --version | head -2 | tail -1)"
             '';
           };
         }
diff --git a/ppad-sha512.cabal b/ppad-sha512.cabal
@@ -14,6 +14,11 @@ description:
   A pure implementation of SHA-512 and HMAC-SHA512 on strict and lazy
   ByteStrings, as specified by RFC's 6234 and 2104.
 
+flag llvm
+  description: Use GHC's LLVM backend.
+  default:     False
+  manual:      True
+
 source-repository head
   type:     git
   location: git.ppad.tech/sha512.git
@@ -23,6 +28,8 @@ library
   hs-source-dirs:   lib
   ghc-options:
       -Wall
+  if flag(llvm)
+    ghc-options: -fllvm -O2
   exposed-modules:
       Crypto.Hash.SHA512
   build-depends: