bug #837: Always re-align the result of EIGEN_ALLOCA.
diff --git a/Eigen/src/Core/util/Memory.h b/Eigen/src/Core/util/Memory.h
index 9718ef6..dd92857 100644
--- a/Eigen/src/Core/util/Memory.h
+++ b/Eigen/src/Core/util/Memory.h
@@ -607,12 +607,9 @@
* The underlying stack allocation function can controlled with the EIGEN_ALLOCA preprocessor token.
*/
#ifdef EIGEN_ALLOCA
- // The native alloca() that comes with llvm aligns buffer on 16 bytes even when AVX is enabled.
-#if defined(__arm__) || defined(_WIN32) || EIGEN_ALIGN_BYTES > 16
- #define EIGEN_ALIGNED_ALLOCA(SIZE) reinterpret_cast<void*>((reinterpret_cast<size_t>(EIGEN_ALLOCA(SIZE+EIGEN_ALIGN_BYTES)) & ~(size_t(EIGEN_ALIGN_BYTES-1))) + EIGEN_ALIGN_BYTES)
- #else
- #define EIGEN_ALIGNED_ALLOCA EIGEN_ALLOCA
- #endif
+ // We always manually re-align the result of EIGEN_ALLOCA.
+ // If alloca is already aligned, the compiler should be smart enough to optimize away the re-alignment.
+ #define EIGEN_ALIGNED_ALLOCA(SIZE) reinterpret_cast<void*>((reinterpret_cast<size_t>(EIGEN_ALLOCA(SIZE+EIGEN_ALIGN_BYTES-1)) + EIGEN_ALIGN_BYTES-1) & ~(size_t(EIGEN_ALIGN_BYTES-1)))
#define ei_declare_aligned_stack_constructed_variable(TYPE,NAME,SIZE,BUFFER) \
Eigen::internal::check_size_for_overflow<TYPE>(SIZE); \
