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Add additional warning flags for dev builds not enabled by Wall or Wextra #8283

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Merged
Jacobfaib merged 2 commits into from
Apr 8, 2026
Merged

Add additional warning flags for dev builds not enabled by Wall or Wextra #8283

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df73f52
Add additional warning flags for dev builds not enabled by Wall or We…
Jacobfaib Apr 2, 2026
df7db2d
fixup! Add additional warning flags for dev builds not enabled by Wal…
Jacobfaib Apr 8, 2026
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34 changes: 34 additions & 0 deletions cmake/CCCLBuildCompilerTargets.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -185,6 +185,40 @@ function(cccl_build_compiler_targets)
append_option_if_available("-Wunused-local-typedefs" cxx_compile_options)
append_option_if_available("-Wvla" cxx_compile_options)

# Clang-only
append_option_if_available("-Wnvcc-compat" cxx_compile_options)
append_option_if_available("-Wimplicit-fallthrough" cxx_compile_options)
append_option_if_available(
"-fdiagnostics-show-template-tree"
cxx_compile_options
)
append_option_if_available("-Wignored-qualifiers" cxx_compile_options)
append_option_if_available(
"-Wmissing-field-initializers"
cxx_compile_options
)
# Inundated with error: ISO C++11 requires at least one argument for the "..." in a
# variadic macro for _CCCL_REQUIRES_EXPR(), so cannot enable this.
#
# append_option_if_available("-pedantic" cxx_compile_options)
append_option_if_available("-Wsign-compare" cxx_compile_options)
append_option_if_available(
"-Warray-bounds-pointer-arithmetic"
cxx_compile_options
)
append_option_if_available("-Wassign-enum" cxx_compile_options)
append_option_if_available("-Wformat-pedantic" cxx_compile_options)
append_option_if_available("-Walloc-size" cxx_compile_options)
append_option_if_available("-Walloc-zero" cxx_compile_options)
append_option_if_available("-Wtsan" cxx_compile_options)
append_option_if_available("-Wenum-conversion" cxx_compile_options)
append_option_if_available("-Wpacked" cxx_compile_options)
# Clang and GCC
append_option_if_available(
"-ftemplate-backtrace-limit=0"
cxx_compile_options
)
append_option_if_available("-fmacro-backtrace-limit=0" cxx_compile_options)
# Disable GNU extensions (flag is clang only)
append_option_if_available("-Wgnu" cxx_compile_options)
append_option_if_available("-Wno-gnu-line-marker" cxx_compile_options) # WAR 3916341
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4 changes: 3 additions & 1 deletion cudax/test/execution/test_stream_context.cu
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Expand Up @@ -14,6 +14,8 @@
// Then include the test helpers
#include <thrust/equal.h>

#include <cuda/std/cstddef>

#include <cuda/experimental/container.cuh>
#include <cuda/experimental/memory_resource.cuh>

Expand Down Expand Up @@ -150,7 +152,7 @@ void bulk_on_stream_scheduler()
| ex::bulk(ex::par_unseq, 10, [] __host__ __device__(int i, cuda::std::span<int> data) -> void {
printf("Hello from bulk kernel on device! i = %d\n", i);
CUDAX_CHECK(_is_on_device());
CUDAX_CHECK(i < data.size());
CUDAX_CHECK(static_cast<::cuda::std::size_t>(i) < data.size());
data[i] += 2;
});

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3 changes: 3 additions & 0 deletions cudax/test/stf/reclaiming/stream.cu
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Expand Up @@ -115,6 +115,9 @@ int main(int argc, char** argv)

::std::vector<logical_data<slice<char>>> handles(nblocks);

EXPECT(nblocks > 0);
EXPECT(block_size > 0);

char* h_buffer = new char[nblocks * block_size];

for (int i = 0; i < nblocks; i++)
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2 changes: 1 addition & 1 deletion libcudacxx/include/cuda/std/__cccl/attributes.h
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Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,7 @@
// NVCC does not properly respect [[assume()]], so use __builtin_assume, see nvbug5458663
#if _CCCL_CUDA_COMPILER(NVCC) && _CCCL_DEVICE_COMPILATION()
# define _CCCL_ASSUME(...) __builtin_assume(__VA_ARGS__)
#elif _CCCL_HAS_CPP_ATTRIBUTE(assume)
#elif _CCCL_HAS_CPP_ATTRIBUTE(assume) && (_CCCL_STD_VER >= 2023)
# define _CCCL_ASSUME(...) [[assume(__VA_ARGS__)]]
Comment on lines +81 to 82
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@bernhardmgruber bernhardmgruber Apr 8, 2026

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Q: Why shouldn't we use the attribute if the compiler supports it before C++23?

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@Jacobfaib Jacobfaib Apr 8, 2026

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clang warns with -Wc++23-compat. I consider this a bug, TBH, that it allows you to use [[assume]] but tells you off for doing so.

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@bernhardmgruber bernhardmgruber Apr 8, 2026

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Do we care about the -Wc++23-compat warning?

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@Jacobfaib Jacobfaib Apr 8, 2026

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Until we start comprehensively testing C++23, I think we should heed the warning. Our CI matrix only goes to C++20 for now.

Note this warning actually only fired due to a previous version of this PR where I also had -pedantic enabled, but that resulted in so many warnings that I turned it off and hope that someone else eventually becomes motivated enough to fix that :)

#else
# define _CCCL_ASSUME(...) _CCCL_BUILTIN_ASSUME(__VA_ARGS__)
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2 changes: 1 addition & 1 deletion libcudacxx/test/libcudacxx/cuda/ccclrt/algorithm/fill.cu
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Expand Up @@ -38,7 +38,7 @@ C2H_CCCLRT_TEST("Fill", "[algorithm]")

cuda::std::span<int> span(buffer.data(), 0);
cuda::fill_bytes(_stream, span, fill_byte);
printf("0 sized span: %p\n", span.data());
printf("0 sized span: %p\n", static_cast<void*>(span.data()));
}
}

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6 changes: 6 additions & 0 deletions thrust/testing/preprocessor.cu
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Expand Up @@ -53,6 +53,8 @@ void test_pp_stringize()
, "'hello world'"
);

_CCCL_DIAG_PUSH
_CCCL_DIAG_SUPPRESS_CLANG("-Wdollar-in-identifier-extension")
ASSERT_EQUAL(
std::string(THRUST_PP_STRINGIZE($%!&<->))
, "$%!&<->"
Expand All @@ -62,6 +64,7 @@ void test_pp_stringize()
std::string(THRUST_PP_STRINGIZE($%!&""<->))
, "$%!&\"\"<->"
);
_CCCL_DIAG_POP

ASSERT_EQUAL(
std::string(THRUST_PP_STRINGIZE(THRUST_PP_STRINGIZE))
Expand Down Expand Up @@ -177,6 +180,8 @@ void test_pp_expand()
, "'hello world'"
);

_CCCL_DIAG_PUSH
_CCCL_DIAG_SUPPRESS_CLANG("-Wdollar-in-identifier-extension")
ASSERT_EQUAL(
std::string(THRUST_PP_STRINGIZE(THRUST_PP_EXPAND($%!&<->)))
, "$%!&<->"
Expand All @@ -186,6 +191,7 @@ void test_pp_expand()
std::string(THRUST_PP_STRINGIZE(THRUST_PP_EXPAND($%!&""<->)))
, "$%!&\"\"<->"
);
_CCCL_DIAG_POP

ASSERT_EQUAL(
std::string(THRUST_PP_STRINGIZE(THRUST_PP_EXPAND(THRUST_PP_EXPAND)))
Expand Down
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