0e34c1dfac5f55d58cf16197b3e87f49089a5339 - toolchain/llvm-project

commit	0e34c1dfac5f55d58cf16197b3e87f49089a5339	[log] [tgz]
author	Jakob Stoklund Olesen <stoklund@2pi.dk>	Wed Apr 20 18:19:48 2011 +0000
committer	Jakob Stoklund Olesen <stoklund@2pi.dk>	Wed Apr 20 18:19:48 2011 +0000
tree	d962d8b816d631b41da1bb3f6124d029ebda2d02
parent	d828f316afaaf6825ea968eac5a46d34d375810d [diff]

Prefer cheap registers for busy live ranges.

On the x86-64 and thumb2 targets, some registers are more expensive to encode
than others in the same register class.

Add a CostPerUse field to the TableGen register description, and make it
available from TRI->getCostPerUse. This represents the cost of a REX prefix or a
32-bit instruction encoding required by choosing a high register.

Teach the greedy register allocator to prefer cheap registers for busy live
ranges (as indicated by spill weight).

llvm-svn: 129864

llvm/include/llvm/Target/Target.td[diff]
llvm/include/llvm/Target/TargetRegisterInfo.h[diff]
llvm/lib/CodeGen/RegAllocBasic.cpp[diff]
llvm/lib/CodeGen/RegAllocGreedy.cpp[diff]
llvm/lib/Target/ARM/ARMRegisterInfo.td[diff]
llvm/lib/Target/X86/X86RegisterInfo.td[diff]
llvm/utils/TableGen/CodeGenRegisters.h[diff]
llvm/utils/TableGen/CodeGenTarget.cpp[diff]
llvm/utils/TableGen/RegisterInfoEmitter.cpp[diff]

9 files changed

tree: d962d8b816d631b41da1bb3f6124d029ebda2d02

clang/
compiler-rt/
debuginfo-tests/
libcxx/
lldb/
llvm/