CUDA: Defer architecture testing to the compiler testing step

Verifying the architectures during compiler identification is redundant,
and requires a lot more up-front information than we should need.
It also causes unsupported architectures to break the compiler id and
version detection, so the resulting output from CMake does not report
the compiler version, which is useful information to know why the
specified architectures are not supported.

The "detecting compiler ABI info" and "check for working compiler" steps
already pass `CMAKE_CUDA_ARCHITECTURES` into their test projects.
Therefore we can just drop the earlier architecture testing.  Bad
architectures will be reported as a not-working compiler, and the
output will include the compiler's error message.

This reverts the approach from:

* commit 19cc5bc296 (CUDA: Throw error if user-specified architectures
                     don't work, 2020-05-26, v3.18.0-rc1~79^2)
* commit 650c1029a0 (CUDA: Detect non-working user-specified architectures
                     on NVCC, 2020-05-28, v3.18.0-rc1~51^2)
* commit 01428c5560 (CUDA: Fail fast if CMAKE_CUDA_ARCHITECTURES
                     doesn't work during detection,
                     2020-08-29, v3.19.0-rc1~241^2).

Their goal was in part to avoid waiting until the test for working
compiler to detect unsupported architectures.  However, experience has
shown that failing earlier is more trouble than it's worth.

Fixes: #23161
Issue: #20756

1 files changed, 1 insertions, 7 deletions

diff --git a/Modules/CMakeDetermineCompilerId.cmake b/Modules/CMakeDetermineCompilerId.cmake
index a90fa5d..0e8b2af 100644
--- a/Modules/CMakeDetermineCompilerId.cmake
+++ b/Modules/CMakeDetermineCompilerId.cmake
@@ -495,13 +495,7 @@ Id flags: ${testflags} ${CMAKE_${lang}_COMPILER_ID_FLAGS_ALWAYS}
       if(CMAKE_VS_PLATFORM_NAME STREQUAL x64)
         set(cuda_target "<TargetMachinePlatform>64</TargetMachinePlatform>")
       endif()
-      if(CMAKE_CUDA_ARCHITECTURES AND NOT CMAKE_CUDA_ARCHITECTURES MATCHES "^(all|all-major|native)$")
-        foreach(arch ${CMAKE_CUDA_ARCHITECTURES})
-          string(REGEX MATCH "[0-9]+" arch_name "${arch}")
-          string(APPEND cuda_codegen "compute_${arch_name},sm_${arch_name};")
-        endforeach()
-      endif()
-      set(id_ItemDefinitionGroup_entry "<CudaCompile>${cuda_target}<AdditionalOptions>%(AdditionalOptions)-v</AdditionalOptions><CodeGeneration>${cuda_codegen}</CodeGeneration></CudaCompile>")
+      set(id_ItemDefinitionGroup_entry "<CudaCompile>${cuda_target}<AdditionalOptions>%(AdditionalOptions)-v</AdditionalOptions></CudaCompile>")
       set(id_PostBuildEvent_Command [[echo CMAKE_CUDA_COMPILER=$(CudaToolkitBinDir)\nvcc.exe]])
       if(CMAKE_VS_PLATFORM_TOOLSET_CUDA_CUSTOM_DIR)
         # check for legacy cuda custom toolkit folder structure