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path: root/llvm/lib/CodeGen/RegisterClassInfo.h
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* Starting to refactor Target to separate out code that's needed to fully describeEvan Cheng2011-06-241-1/+1
| | | | | | | | | | | | target machine from those that are only needed by codegen. The goal is to sink the essential target description into MC layer so we can start building MC based tools without needing to link in the entire codegen. First step is to refactor TargetRegisterInfo. This patch added a base class MCRegisterInfo which TargetRegisterInfo is derived from. Changed TableGen to separate register description from the rest of the stuff. llvm-svn: 133782
* Avoid calling TRI->getAllocatableSet in RAFast.Jakob Stoklund Olesen2011-06-021-0/+19
| | | | | | | | | | | | | | When compiling a program with lots of small functions like 483.xalancbmk, this makes RAFast 11% faster. Add some comments to clarify the difference between unallocatable and reserved registers. It's quite subtle. The fast register allocator depends on EFLAGS' not being allocatable on x86. That way it can completely avoid tracking liveness, and it won't mind when there are multiple uses of a single def. llvm-svn: 132514
* Just use a SmallVector.Jakob Stoklund Olesen2011-06-021-1/+1
| | | | | | | | | I was confused whether new uint8_t[] would zero-initialize the returned array, and it seems that so is gcc-4.0. This should fix the test failures on darwin 9. llvm-svn: 132500
* Add a RegisterClassInfo class that lazily caches information aboutJakob Stoklund Olesen2011-06-021-0/+102
register classes. It provides information for each register class that cannot be determined statically, like: - The number of allocatable registers in a class after filtering out the reserved and invalid registers. - The preferred allocation order with registers that overlap callee-saved registers last. - The last callee-saved register that overlaps a given physical register. This information usually doesn't change between functions, so it is reused for compiling multiple functions when possible. The many possible combinations of reserved and callee saves registers makes it unfeasible to compute this information statically in TableGen. Use RegisterClassInfo to count available registers in various heuristics in SimpleRegisterCoalescing, making the pass run 4% faster. llvm-svn: 132450
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