Bundled Eigen is broken for Darwin PowerPC: either update to a newer version or at least disable Altivec for Darwin

[barracuda156]

Upstream eigen has merged a fix for Darwin PowerPC quite some time ago, AFAIK it should work, at least I use devel branch for building ports and nothing so far fails. However Boom uses, apparently, quite old eigen, which breaks the build, since unsupported VSX instructions are pulled in.

A quick-n-dirty fix will be disabling Altivec/VSX like this:

--- inst/include/Eigen/Core	2023-12-18 01:53:40.000000000 +0800
+++ inst/include/Eigen/Core	2023-12-19 02:58:58.000000000 +0800
@@ -206,7 +206,7 @@
   #include "src/Core/arch/SSE/TypeCasting.h"
   #include "src/Core/arch/SSE/MathFunctions.h"
   #include "src/Core/arch/SSE/Complex.h"
-#elif defined(EIGEN_VECTORIZE_ALTIVEC) || defined(EIGEN_VECTORIZE_VSX)
+#elif (defined(EIGEN_VECTORIZE_ALTIVEC) || defined(EIGEN_VECTORIZE_VSX)) && !defined(__APPLE__)
   #include "src/Core/arch/AltiVec/PacketMath.h"
   #include "src/Core/arch/AltiVec/MathFunctions.h"
   #include "src/Core/arch/AltiVec/Complex.h"
@@ -346,7 +346,7 @@
 #include "src/Core/CoreIterators.h"
 #include "src/Core/ConditionEstimator.h"
 
-#if defined(EIGEN_VECTORIZE_ALTIVEC) || defined(EIGEN_VECTORIZE_VSX)
+#if (defined(EIGEN_VECTORIZE_ALTIVEC) || defined(EIGEN_VECTORIZE_VSX)) && !defined(__APPLE__)
   #include "src/Core/arch/AltiVec/MatrixProduct.h"
 #elif defined EIGEN_VECTORIZE_NEON
   #include "src/Core/arch/NEON/GeneralBlockPanelKernel.h"

[barracuda156]

@steve-the-bayesian I could make a PR with this, if it makes it easier. Not using a bit of supported altivec on G5 is definitely better than having the build broken :)

As I recall, backporting may not be trivial, so until eigen is updated, rather disable simd on Darwin ppc.

[barracuda156]

Or even better if there will be an option to use an external Eigen.

[steve-the-bayesian]

I tried updating Eigen to 3.4 on a recent build. No code changed? I'd be curious to see your PR.

…

On Sat, Feb 3, 2024 at 3:40 PM Sergey Fedorov ***@***.***> wrote: Or even better if there will be an option to use an external Eigen. — Reply to this email directly, view it on GitHub <#78 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABMVDVLU2RL26L6ODUP44SLYR3DFPAVCNFSM6AAAAABA2D242SVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMRVGQ4DOMBYGE> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[barracuda156]

I tried updating Eigen to 3.4 on a recent build. No code changed? I'd be curious to see your PR.

The issue was fixed in Eigen master in https://gitlab.com/libeigen/eigen/-/merge_requests/1150
So 3.4 still has the bug.