llvm

4cb26171 - [sycl-jit] Allow GCC host builds by not elevating -Wconversion to errors (#21933)

[sycl-jit] Allow GCC host builds by not elevating -Wconversion to errors (#21933) ## Summary Add `-Wno-error=conversion` **only** for the `sycl-jit` target under g++ compiler so the SYCL JIT library can be built when the LLVM/SYCL tree is configured with **GNU `g++` as the host C++ compiler**, while keeping `-Wconversion` and the rest of `SYCL_JIT_WARNING_FLAGS` / `-Werror` behavior for other diagnostics or for other compilers. ## Problem With `SYCL_JIT_ENABLE_WERROR` on (default), `sycl-jit` uses `-Wall -Wextra -Wconversion -Werror`. Compiling `lib/rtc/DeviceCompilation.cpp` pulls in Clang headers (e.g. via the Driver). Under **g++ 13.3.0** (`/usr/bin/g++`, Ubuntu `13.3.0-6ubuntu2~24.04.1`), those headers trigger a large number of **`-Wconversion`** warnings, which **fail the build** under `-Werror`. ## Solution `target_compile_options(sycl-jit PRIVATE -Wno-error=conversion)` in `sycl-jit/jit-compiler/CMakeLists.txt`: conversion issues are still reported as **warnings** for g++, but no longer abort the `sycl-jit` build. ## Compilation errors observed (representative) The build stopped on `DeviceCompilation.cpp` with warnings treated as errors, for example: ```text FAILED: tools/sycl-jit/jit-compiler/CMakeFiles/sycl-jit.dir/lib/rtc/DeviceCompilation.cpp.o .../install_.../include/clang/Basic/FileEntry.h:251:22: error: conversion from 'size_t' {aka 'long unsigned int'} to 'unsigned int' may change value [-Werror=conversion] .../install_.../include/clang/Basic/DiagnosticIDs.h:124:23: error: conversion from 'unsigned int' to 'unsigned char:3' may change value [-Werror=conversion] .../install_.../include/clang/Basic/LangOptions.h:688:12: error: conversion from 'unsigned int' to 'unsigned char:2' may change value [-Werror=conversion] .../install_.../include/clang/Basic/TargetInfo.h:559:51: error: conversion from 'uint64_t' {aka 'long unsigned int'} to 'unsigned int' may change value [-Werror=conversion] .../install_.../include/clang/Frontend/FrontendOptions.h:188:22: error: conversion from 'unsigned int' to 'unsigned char:3' may change value [-Werror=conversion] cc1plus: all warnings being treated as errors ninja: build stopped: subcommand failed. ``` ## Host toolchain CMAKE_CXX_COMPILER=/usr/bin/g++ g++ (Ubuntu 13.3.0-6ubuntu2~24.04.1) 13.3.0 ## Testing Reconfigured and rebuilt the project with the existing configure/build workflow; sycl-jit and SYCL install steps complete with this change.