From 791d0133cc0d2499a84dd94e898c18cbb58c899e Mon Sep 17 00:00:00 2001
From: Gianfranco Costamagna <costamagnagianfranco@yahoo.it>
Date: Wed, 8 May 2024 17:11:54 +0200
Subject: [PATCH] Update type_traits.h. (#402)

* Update type_traits.h.

A regression was introduced in 2b80e29803d60f01701a67bc57ef06dacfe8af8b. In case of THRUST_DEVICE_SYSTEM_OMP build, the invoke_result_t is undefined due to missing #else branch.
See e.g. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1064730

* fix(detail/nv_target.h): include missing target macros when targetting a non-hip backend (i.e. openmp)

This change causes the HIP system target.h to be included when targetting a device system that is not HIP or CUDA.

---------

Co-authored-by: Nara Prasetya <nara@streamhpc.com>
---
 thrust/detail/nv_target.h   | 4 ++++
 thrust/detail/type_traits.h | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/thrust/detail/nv_target.h b/thrust/detail/nv_target.h
index 1f93a096b..131ca720a 100644
--- a/thrust/detail/nv_target.h
+++ b/thrust/detail/nv_target.h
@@ -27,4 +27,8 @@
 #  include <thrust/system/hip/detail/nv/target.h>
 #elif THRUST_DEVICE_SYSTEM == THRUST_DEVICE_SYSTEM_CUDA
 #  include <nv/target>
+#else
+// When using a different backend, e.g. OpenMP, we still need to define the target.
+// We can simply reuse the HIP targets for this.
+#  include <thrust/system/hip/detail/nv/target.h>
 #endif
diff --git a/thrust/detail/type_traits.h b/thrust/detail/type_traits.h
index 31493c80b..60410cb5d 100644
--- a/thrust/detail/type_traits.h
+++ b/thrust/detail/type_traits.h
@@ -731,6 +731,8 @@ using invoke_result_t =
 #else // 2017+
   ::cuda::std::invoke_result_t<Invokable, Args...>;
 #endif
+#else
+  std::invoke_result_t<Invokable, Args...>;
 #endif
 
 template <class F, class... Us>