This makes it possible for runtime implementations to disable
subnormal handling at runtime.
When this flag is enabled, decisions about how to handle subnormals
in the library will be controlled by an external variable called
__CLC_SUBNORMAL_DISABLE.
Function implementations should use these new helpers for querying subnormal
support:
__clc_fp16_subnormals_supported();
__clc_fp32_subnormals_supported();
__clc_fp64_subnormals_supported();
In order for the library to link correctly with this feature,
users will be required to either:
1. Insert this variable into the module (if using the LLVM/Clang C++/C APIs).
2. Pass either subnormal_disable.bc or subnormal_use_default.bc to the
linker. These files are distributed with liblclc and installed to
$(installdir). e.g.:
llvm-link -o kernel-out.bc kernel.bc builtins-nosubnormal.bc subnormal_disable.bc
or
llvm-link -o kernel-out.bc kernel.bc builtins-nosubnormal.bc subnormal_use_default.bc
If you do not supply the --enable-runtime-subnormal then the library
behaves the same as it did before this commit.
In addition to these changes, the patch adds helper functions that
should be used when implementing library functions that need
special handling for denormals:
__clc_fp16_subnormals_supported();
__clc_fp32_subnormals_supported();
__clc_fp64_subnormals_supported();
llvm-svn: 235329
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libclc
------
libclc is an open source, BSD licensed implementation of the library
requirements of the OpenCL C programming language, as specified by the
OpenCL 1.1 Specification. The following sections of the specification
impose library requirements:
*6.1: Supported Data Types
*6.2.3: Explicit Conversions
*6.2.4.2: Reinterpreting Types Using as_type() and as_typen()
*6.9: Preprocessor Directives and Macros
*6.11: Built-in Functions
*9.3: Double Precision Floating-Point
*9.4: 64-bit Atomics
*9.5: Writing to 3D image memory objects
*9.6: Half Precision Floating-Point
libclc is intended to be used with the Clang compiler's OpenCL frontend.
libclc is designed to be portable and extensible. To this end, it provides
generic implementations of most library requirements, allowing the target
to override the generic implementation at the granularity of individual
functions.
libclc currently only supports the PTX target, but support for more
targets is welcome.
Compiling and installing with Make
----------------------------------
$ ./configure.py --with-llvm-config=/path/to/llvm-config && make
$ make install
Note you can use the DESTDIR Makefile variable to do staged installs.
$ make install DESTDIR=/path/for/staged/install
Compiling and installing with Ninja
-----------------------------------
$ ./configure.py -g ninja --with-llvm-config=/path/to/llvm-config && ninja
$ ninja install
Note you can use the DESTDIR environment variable to do staged installs.
$ DESTDIR=/path/for/staged/install ninja install
Website
-------
http://www.pcc.me.uk/~peter/libclc/
d9ca1f1596