Clement Courbet 9c2e0e0fa4 [llvm-exegesis] Add loop mode for repeating the snippet. ... Summary: Before this change the Executable function was made by duplicating the snippet. This change adds a --repetion-mode={loop|duplicate} flag that allows choosing between this behaviour and wrapping the snippet instructions in a loop. The new mode can help measurements when the snippet fits in the DSB by short-cirtcuiting decoding. The loop adds a dec + jmp to the measurements, but since these are not part of the critical path, they execute in parallel with the measured code and do not impact measurements in practice. Overview of the change: - New SnippetRepetitor abstraction that handles repeating the snippet. The assembler delegates repeating the instructions to this class. - ExegesisTarget learns how to decrement loop counter and jump. - Some refactoring of the assembler into FunctionFiller/BasicBlockFiller. Reviewers: gchatelet Subscribers: mgorny, tschuett, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D68125 llvm-svn: 373083		2019-09-27 12:56:24 +00:00
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AssemblerUtils.h