[OpenCL] Generate 'unroll.enable' metadata for __attribute__((opencl_unroll_hint))
Summary:
[OpenCL] Generate 'unroll.enable' metadata for __attribute__((opencl_unroll_hint))
For both !{!"llvm.loop.unroll.enable"} and !{!"llvm.loop.unroll.full"} the unroller
will try to fully unroll a loop unless the trip count is not known at compile time.
In that case for '.full' metadata no unrolling will be processed, while for '.enable'
the loop will be partially unrolled with a heuristically chosen unroll factor.
See: docs/LanguageExtensions.rst
From https://www.khronos.org/registry/OpenCL/sdk/2.0/docs/man/xhtml/attributes-loopUnroll.html
__attribute__((opencl_unroll_hint))
for (int i=0; i<2; i++)
{
...
}
In the example above, the compiler will determine how much to unroll the loop.
Before the patch for __attribute__((opencl_unroll_hint)) was generated metadata
!{!"llvm.loop.unroll.full"}, which limits ability of loop unroller to decide, how
much to unroll the loop.
Reviewers: Anastasia, yaxunl
Reviewed By: Anastasia
Subscribers: zzheng, dmgreen, jdoerfert, cfe-commits, asavonic, AlexeySotkin
Tags: #clang
Differential Revision: https://reviews.llvm.org/D59493
llvm-svn: 356571
2 files changed