message: Switch to GCC 6 and CUDA 9.1 container because building with optimizations on CUDA 9.0 with GCC 5.5 fails due to some weird CUDA/GCC interaction.
  See also: this[1] Tensorflow issue and many other.
  [1]:
diff: @@ -189,9 +189,9 @@ build/nocuda/gcc/omp/debug:
  BUILD_OMP: "ON"
  # Release builds
  -build/cuda90/gcc/all/release:
  +build/cuda91/gcc/all/release:
  <<: *default_build
  - image: localhost:5000/gko-cuda90-gnu5-llvm39
  + image: localhost:5000/gko-cuda91-gnu6-llvm40
  variables:
  <<: *default_variables
  BUILD_OMP: "ON"
  @@ -200,9 +200,9 @@ build/cuda90/gcc/all/release:
  EXTRA_CMAKE_FLAGS: &cuda_flags
  -DCUDA_ARCHITECTURES=35
  -build/cuda90/clang/all/release:
  +build/cuda91/clang/all/release:
  <<: *default_build
  - image: localhost:5000/gko-cuda90-gnu5-llvm39
  + image: localhost:5000/gko-cuda91-gnu6-llvm40
  variables:
  <<: *default_variables
  C_COMPILER: clang
  @@ -303,17 +303,17 @@ test/nocuda/gcc/omp/debug:
  - build/nocuda/gcc/omp/debug
  # Release tests
  -test/cuda90/gcc/all/release:
  +test/cuda91/gcc/all/release:
  <<: *default_test
  - image: localhost:5000/gko-cuda90-gnu5-llvm39
  + image: localhost:5000/gko-cuda91-gnu6-llvm40
  dependencies:
  - - build/cuda90/gcc/all/release
  + - build/cuda91/gcc/all/release
  -test/cuda90/clang/all/release:
  +test/cuda91/clang/all/release:
  <<: *default_test
  - image: localhost:5000/gko-cuda90-gnu5-llvm39
  + image: localhost:5000/gko-cuda91-gnu6-llvm40
  dependencies:
  - - build/cuda90/clang/all/release
  + - build/cuda91/clang/all/release
  test/nocuda/gcc/omp/release:
  <<: *default_test
  