llvm-project/llvm
Matt Arsenault 68d938649e Introduce target hook for optimizing register copies
Allow a target to do something other than search for copies
that will avoid cross register bank copies.

Implement for SI by only rewriting the most basic copies,
so it should look through anything like a subregister extract.

I'm not entirely satisified with this because it seems like
eliminating a reg_sequence that isn't fully used should work
generically for all targets without them having to override
something. However, it seems to be tricky to have a simple
implementation of this without rewriting to invalid  kinds
of subregister copies on some targets.

I'm not sure if there is currently a generic way to easily check
if a subregister index would be valid for the current use.
The current set of TargetRegisterInfo::get*Class functions don't
quite behave like I would expect (e.g. getSubClassWithSubReg
returns the maximal register class rather than the minimal), so
I'm not sure how to make the generic test keep searching if
SrcRC:SrcSubReg is a valid replacement for DefRC:DefSubReg. Making
the default implementation to check for simple copies breaks
a variety of ARM and x86 tests by producing illegal subregister uses.

The ARM tests are not actually changed since it should still be using
the same sharesSameRegisterFile implementation, this just relaxes
them to not check for specific registers.

llvm-svn: 248478
2015-09-24 08:36:14 +00:00
..
autoconf Don't use bashism/kshism of test ==. From Kamil Rytarowski. 2015-09-12 16:30:32 +00:00
bindings [bindings] Update Go bindings to DIBuilder 2015-09-06 02:22:15 +00:00
cmake [CMake] Adding ALWAYS_GENERATE option to symlink utility functions. 2015-09-18 21:08:32 +00:00
docs Nit cleanup in LangRef about dereferenceable metadata 2015-09-18 12:07:10 +00:00
examples Fix typo and test commit 2015-09-18 21:15:45 +00:00
include Introduce target hook for optimizing register copies 2015-09-24 08:36:14 +00:00
lib Introduce target hook for optimizing register copies 2015-09-24 08:36:14 +00:00
projects
resources
test Introduce target hook for optimizing register copies 2015-09-24 08:36:14 +00:00
tools dsymutil: Don't prune forward declarations inside a module definition. 2015-09-23 20:44:37 +00:00
unittests Add a unit test for r248341. 2015-09-22 23:42:47 +00:00
utils TableGen: Add LLVM_READONLY to generated InstrMapping functions 2015-09-24 07:51:20 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [CMake] [Darwin] Need to set lto_library on CMAKE_MODULE_LINKER_FLAGS as well 2015-09-11 18:39:19 +00:00
CODE_OWNERS.TXT CODE_OWNERS.TXT is supposed to be sorted by surname 2015-09-07 00:41:40 +00:00
CREDITS.TXT
LICENSE.TXT
LLVMBuild.txt
Makefile
Makefile.common
Makefile.config.in We're actually -Wmissing-field-initializers clean thanks to the cmake 2015-08-07 16:44:47 +00:00
Makefile.rules We're actually -Wmissing-field-initializers clean thanks to the cmake 2015-08-07 16:44:47 +00:00
README.txt
configure Don't use bashism/kshism of test ==. From Kamil Rytarowski. 2015-09-12 16:30:32 +00:00
llvm.spec.in [Sparc] Implement i64 load/store support for 32-bit sparc. 2015-08-10 19:11:39 +00:00

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