[ROCm][Windows] Fix LoadHIP handling of environment variable paths on Windows. (#159080)

ScottTodd · pytorchmergebot · commit ee89cc7a0acd · 2025-08-12T00:18:19.000Z
See https://cmake.org/cmake/help/latest/command/file.html#path-conversion. Paths stored in environment variables may use `/` or `\` (e.g. on Windows), while cmake-style paths always use `/`. This fixes configure errors like: ``` CMake Error at D:/b/pytorch_main/build/CMakeFiles/CMakeScratch/TryCompile-srhq07/CMakeLists.txt:2 (set): Syntax error in cmake code at D:/b/pytorch_main/build/CMakeFiles/CMakeScratch/TryCompile-srhq07/CMakeLists.txt:2 when parsing string D:\projects\TheRock\external-builds\pytorch\.venv\Lib\site-packages\_rocm_sdk_devel/cmake/;D:/b/pytorch_main/cmake/Modules Invalid character escape '\p'. CMake Error at D:/projects/TheRock/external-builds/pytorch/.venv/Lib/site-packages/cmake/data/share/cmake-3.31/Modules/Internal/CheckSourceCompiles.cmake:108 (try_compile): Failed to configure test project build system. ``` (note the mixed usage of `\` and `/` in that string) Pull Request resolved: #159080 Approved by: https://github.com/jeffdaily
diff --git a/cmake/public/LoadHIP.cmake b/cmake/public/LoadHIP.cmake
@@ -6,7 +6,7 @@ set(PYTORCH_FOUND_HIP FALSE)
 # In the latter case, if /opt/rocm does not exist emit status
 # message and return.
 if(DEFINED ENV{ROCM_PATH})
-  set(ROCM_PATH $ENV{ROCM_PATH})
+  file(TO_CMAKE_PATH "$ENV{ROCM_PATH}" ROCM_PATH)
   if(NOT EXISTS ${ROCM_PATH})
     message(FATAL_ERROR
       "ROCM_PATH environment variable is set to ${ROCM_PATH} but does not exist.\n"
@@ -31,7 +31,7 @@ if(NOT DEFINED ENV{MAGMA_HOME})
   set(MAGMA_HOME ${ROCM_PATH}/magma)
   set(ENV{MAGMA_HOME} ${ROCM_PATH}/magma)
 else()
-  set(MAGMA_HOME $ENV{MAGMA_HOME})
+  file(TO_CMAKE_PATH "$ENV{MAGMA_HOME}" MAGMA_HOME)
 endif()
 
 # MIOpen isn't a part of HIP-SDK for Windows and hence, may have a different
