USE_ARCH flag work for Heterogenous Galois too

[ddn0]

Not a blocker, but we should make the USE_ARCH flag work everywhere. Even for Heterogeneous Galois, we can still set the architecture flag for all the CPU code generated.

Originally posted by @insertinterestingnamehere in #88

[roshandathathri]

I did not understand this. Why do we need this?

[ddn0]

It is a little unexpected that USE_ARCH is completely ignored if ENABLE_HETERO_GALOIS=ON since those two options are not related to each other for CPU code.

https://github.com/IntelligentSoftwareSystems/Galois/blob/master/CMakeLists.txt#L69

[insertinterestingnamehere]

Yah, it's an unexpected behavior issue. I'm not aware of anything that makes this urgent. The current behavior is just weird.

[roshandathathri]

What is USE_ARCH expected to do?

I will be renaming ENABLE_HETERO_GALOIS to GALOIS_ENABLE_GPU (and merging it with USE_GPU). That flag will enable single/distributed GPU code for lonestar (analytics/mining/scientific).

[insertinterestingnamehere]

USE_ARCH sets the appropriate -march=... flag for the CPU code.

[roshandathathri]

I don't see USE_ARCH being used anywhere currently. It was being used for KNL if I remember right. But where is that code in our cmake files?

https://github.com/IntelligentSoftwareSystems/Galois/blob/master/CMakeLists.txt#L69

I will drop those lines. They are not related/required.

[insertinterestingnamehere]

It's in https://github.com/IntelligentSoftwareSystems/Galois/blob/master/cmake/Modules/CheckArchFlags.cmake which defined variables that then get pulled in here: https://github.com/IntelligentSoftwareSystems/Galois/blob/master/CMakeLists.txt#L132.

[insertinterestingnamehere]

My best guess is that the if statement at https://github.com/IntelligentSoftwareSystems/Galois/blob/master/CMakeLists.txt#L69 was added to work around some kind of compiler error for the heterogeneous case. @ddn0, you added that, do you remember why it's there?

[roshandathathri]

Thanks, Ian. This is not related to GALOIS_ENABLE_GPU flag, so waiting for Donald's reply to see if he added those lines.

[ddn0]

I added that line to follow the original logic:
68df52e#diff-af3b638bc2a3e6c650974192a53c7291L139

which was added in this commit:
bc691fe

That's where my context ends :D

Unrelated to this issue, I noticed there are still quite a few warnings when compiling gluon (unused parameters) and with gcc 8.4/clang 9, I actually get an internal compiler error:

[ 77%] Building CUDA object lonestar/analytics/gpu/pta/CMakeFiles/pta_gpu.dir/pta.cu.o
...
/home/ddn/w/katana/lonestar/analytics/gpu/pta/andersen.cu(1379): internal error: assertion failed: conv_glvalue_expr_to_prvalue: bad expr (/dvs/p4/build/sw/rel/gpu_drv/r418/TRD418_98/drivers/compiler/edg/EDG_5.0/src/exprutil.c, line 20215)


1 catastrophic error detected in the compilation of "/tmp/tmpxft_00004683_00000000-4_pta.cpp4.ii".

ddn@spork:katana-build$ nvcc --version
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2019 NVIDIA Corporation
Built on Wed_Apr_24_19:10:27_PDT_2019
Cuda compilation tools, release 10.1, V10.1.168

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 13a2e9376..91ed1a9e8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -66,9 +66,9 @@ if(NUM_TEST_THREADS LESS_EQUAL 0)
   set(NUM_TEST_THREADS 1)
 endif()
 
-if(ENABLE_HETERO_GALOIS)
-  set(USE_ARCH none)
-endif()
+# if(ENABLE_HETERO_GALOIS)
+#   set(USE_ARCH none)
+# endif()
 
 ###### Configure (users don't need to go beyond here) ######
 
@@ -93,7 +93,7 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     message(FATAL_ERROR "gcc must be version 7 or higher. Found ${CMAKE_CXX_COMPILER_VERSION}.")
   endif()
 
-  add_compile_options("$<$<COMPILE_LANGUAGE:CXX>:-Wall;-Wextra;-Werror>")
+  add_compile_options("$<$<COMPILE_LANGUAGE:CXX>:-Wall;-Wextra;-Werror;-w>")
 
   if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 9)
     # Avoid warnings from openmpi

[roshandathathri]

which was added in this commit:
bc691fe

Thanks, Donald. This was my commit but those lines were there from a commit before that. It's pretty old. I don't think it's needed.

[roshandathathri]

Unrelated to this issue, I noticed there are still quite a few warnings when compiling gluon (unused parameters) and with gcc 8.4/clang 9, I actually get an internal compiler error:

Are these errors related to commenting out those lines?
"analytics/gpu" is not gluon code. Please raise an issue and assign it to Vishwesh.
If there are still warning on analytics/distributed related to GPU code, please raise an issue for that and assign it to Vishwesh and me.

[ddn0]

Are these errors related to commenting out those lines?
"analytics/gpu" is not gluon code. Please raise an issue and assign it to Vishwesh.
If there are still warning on analytics/distributed related to GPU code, please raise an issue for that and assign it to Vishwesh and me.

There are two issues:

1. warnings in gluon
2. ICE in analytics/gpu

I'll file issues for both.

[roshandathathri]

Thanks!

[roshandathathri]

I made those flags independent in PR 199.