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
algorithm when assigning EnumValues to the synthesized registers. The current algorithm, LessRecord, uses the StringRef compare_numeric function. This function compares strings, while handling embedded numbers. For example, the R600 backend registers are sorted as follows: T1 T1_W T1_X T1_XYZW T1_Y T1_Z T2 T2_W T2_X T2_XYZW T2_Y T2_Z In this example, the 'scaling factor' is dEnum/dN = 6 because T0, T1, T2 have an EnumValue offset of 6 from one another. However, in other parts of the register bank, the scaling factors are different: dEnum/dN = 5: KC0_128_W KC0_128_X KC0_128_XYZW KC0_128_Y KC0_128_Z KC0_129_W KC0_129_X KC0_129_XYZW KC0_129_Y KC0_129_Z The diff lists do not work correctly because different kinds of registers have different 'scaling factors'. This new algorithm, LessRecordRegister, tries to enforce a scaling factor of 1. For example, the registers are now sorted as follows: T1 T2 T3 ... T0_W T1_W T2_W ... T0_X T1_X T2_X ... KC0_128_W KC0_129_W KC0_130_W ... For the Mips and R600 I see a 19% and 6% reduction in size, respectively. I did see a few small regressions, but the differences were on the order of a few bytes (e.g., AArch64 was 16 bytes). I suspect there will be even greater wins for targets with larger register files. Patch reviewed by Jakob. rdar://14006013 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185094 91177308-0d34-0410-b5e6-96231b3b80d8
Low Level Virtual Machine (LLVM) ================================ This directory and its subdirectories contain source code for the Low Level Virtual Machine, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you're writing a package for LLVM, see docs/Packaging.rst for our suggestions.
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