Hal Finkel e30aa957e3 Implement X86TTI::getUnrollingPreferences ... This provides an initial implementation of getUnrollingPreferences for x86. getUnrollingPreferences is used by the generic (concatenation) unroller, which is distinct from the unrolling done by the loop vectorizer. Many modern x86 cores have some kind of uop cache and loop-stream detector (LSD) used to efficiently dispatch small loops, and taking full advantage of this requires unrolling small loops (small here means 10s of uops). These caches also have limits on the number of taken branches in the loop, and so we also cap the loop unrolling factor based on the maximum "depth" of the loop. This is currently calculated with a partial DFS traversal (partial because it will stop early if the path length grows too much). This is still an approximation, and one that is both conservative (because it does not account for branches eliminated via block placement) and optimistic (because it is only recording the maximum depth over minimum paths). Nevertheless, because the loops that fit in these uop caches are so small, it is not clear how much the details matter. The original set of patches posted for review produced the following test-suite performance results (from the TSVC benchmark) at that time: ControlLoops-dbl - 13% speedup ControlLoops-flt - 15% speedup Reductions-dbl - 7.5% speedup git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205348 91177308-0d34-0410-b5e6-96231b3b80d8		2014-04-01 18:50:34 +00:00
..
Analysis	ARM64: initial backend import	2014-03-29 10:18:08 +00:00
Assembler
Bindings
Bitcode
BugPoint
CodeGen	Support segmented stacks on Win64	2014-04-01 18:34:21 +00:00
DebugInfo	DebugInfo: Avoid creating unnecessary/empty line tables and remove the special case of '0' in DwarfCompileUnit::initStmtList by just always using a label difference	2014-04-01 08:07:52 +00:00
ExecutionEngine
Feature	Disable each MachineFunctionPass for 'optnone' functions, unless that	2014-03-31 17:43:35 +00:00
FileCheck
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Integer
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Linker	Switch the type field in DIVariable and DIGlobalVariable over to DITypeRefs.	2014-03-18 02:34:58 +00:00
LTO
MC	[mips] Add Octeon cnMips instructions mtmX and mtpX	2014-04-01 18:35:26 +00:00
Object
Other
TableGen
tools	llvm-cov: Move XFAIL after the body of the test	2014-03-26 22:51:39 +00:00
Transforms	Implement X86TTI::getUnrollingPreferences	2014-04-01 18:50:34 +00:00
Unit
Verifier
YAMLParser
.clang-format	Add .clang-format without column limit to subdirectory tests/.	2013-11-19 04:26:05 +00:00
CMakeLists.txt
lit.cfg	llvm-mc: error when -compress-debug-sections is requested and zlib is not linked	2014-03-28 20:45:24 +00:00
lit.site.cfg.in
Makefile
Makefile.tests
TestRunner.sh	Use exec.	2010-08-29 14:49:00 +00:00