Fix global optimization bug for ChaCha AVX2 under VS2017 (GH #735)

Also see https://github.com/weidai11/cryptopp/issues/649. The 649 issue is the one affecting AES. It appears to be the same problem.

2 files changed, 21 insertions, 6 deletions

diff --git a/chacha-avx.cpp b/chacha-avx.cpp
index 6c875c5f..0aba0a99 100644
--- a/chacha-avx.cpp
+++ b/chacha-avx.cpp
@@ -36,10 +36,21 @@ extern const char CHACHA_AVX_FNAME[] = __FILE__;
 # define MAYBE_CONST const

 #endif

 

-#if (CRYPTOPP_AVX2_AVAILABLE)

+// VS2017 and global optimization bug. TODO, figure out when

+// we can re-enable full optimizations for VS2017. Also see

+// https://github.com/weidai11/cryptopp/issues/649 and

+// https://github.com/weidai11/cryptopp/issues/735. The

+// 649 issue affects AES but it is the same here. The 735

+// issue is ChaCha AVX2 cut-in where it surfaced again.

+#if (_MSC_VER >= 1910) && defined(NDEBUG)

+# pragma optimize("", off)

+# pragma optimize("ts", on)

+#endif

 

 ANONYMOUS_NAMESPACE_BEGIN

 

+#if (CRYPTOPP_AVX2_AVAILABLE)

+

 template <unsigned int R>

 inline __m256i RotateLeft(const __m256i val)

 {

@@ -62,10 +73,14 @@ inline __m256i RotateLeft<16>(const __m256i val)
     return _mm256_shuffle_epi8(val, mask);

 }

 

+#endif CRYPTOPP_AVX2_AVAILABLE

+

 ANONYMOUS_NAMESPACE_END

 

 NAMESPACE_BEGIN(CryptoPP)

 

+#if (CRYPTOPP_AVX2_AVAILABLE)

+

 void ChaCha_OperateKeystream_AVX2(const word32 *state, const byte* input, byte *output, unsigned int rounds)

 {

     MAYBE_CONST __m128i* state_mm = (MAYBE_CONST __m128i*)(state);

@@ -358,6 +373,6 @@ void ChaCha_OperateKeystream_AVX2(const word32 *state, const byte* input, byte *
     }

 }

 

-NAMESPACE_END

-

 #endif  // CRYPTOPP_AVX2_AVAILABLE

+

+NAMESPACE_END

diff --git a/rijndael.cpp b/rijndael.cpp
index f00cc277..3cc0a46b 100644
--- a/rijndael.cpp
+++ b/rijndael.cpp
@@ -88,10 +88,10 @@ being unloaded from L1 cache, until that round is finished.
 #include "misc.h"

 #include "cpu.h"

 

-// MSVC bug, still don't know how to fix it. TODO, figure out

-// when we can re-enable optimizations for MSVC. Also see

+// VS2017 and global optimization bug. TODO, figure out when

+// we can re-enable full optimizations for VS2017. Also see

 // https://github.com/weidai11/cryptopp/issues/649

-#if defined(_MSC_VER) && (_MSC_VER >= 1910)

+#if (_MSC_VER >= 1910) && defined(NDEBUG)

 # pragma optimize("", off)

 # pragma optimize("ts", on)

 #endif