Chandler Carruth df234353fb Rewrite #3 of machine block placement. This is based somewhat on the ... second algorithm, but only loosely. It is more heavily based on the last discussion I had with Andy. It continues to walk from the inner-most loop outward, but there is a key difference. With this algorithm we ensure that as we visit each loop, the entire loop is merged into a single chain. At the end, the entire function is treated as a "loop", and merged into a single chain. This chain forms the desired sequence of blocks within the function. Switching to a single algorithm removes my biggest problem with the previous approaches -- they had different behavior depending on which system triggered the layout. Now there is exactly one algorithm and one basis for the decision making. The other key difference is how the chain is formed. This is based heavily on the idea Andy mentioned of keeping a worklist of blocks that are viable layout successors based on the CFG. Having this set allows us to consistently select the best layout successor for each block. It is expensive though. The code here remains very rough. There is a lot that needs to be done to clean up the code, and to make the runtime cost of this pass much lower. Very much WIP, but this was a giant chunk of code and I'd rather folks see it sooner than later. Everything remains behind a flag of course. I've added a couple of tests to exercise the issues that this iteration was motivated by: loop structure preservation. I've also fixed one test that was exhibiting the broken behavior of the previous version. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144495 91177308-0d34-0410-b5e6-96231b3b80d8		2011-11-13 11:20:44 +00:00
..
Analysis	Don't forget to check FlagNW when determining whether an AddRecExpr will wrap	2011-11-09 07:11:37 +00:00
Archive
Assembler
Bindings/Ocaml
Bitcode
BugPoint
CodeGen	Rewrite #3 of machine block placement. This is based somewhat on the	2011-11-13 11:20:44 +00:00
DebugInfo	The dwarf standard says that the only differences between a out-of-line	2011-11-12 01:57:54 +00:00
ExecutionEngine
Feature
Integer
lib	tests: Rip out a bunch of now unused test code relating to use of llvm-gcc in LLVM tests.	2011-10-27 20:59:26 +00:00
Linker
MC	ARM optional size suffix for VLDR/VSTR syntax.	2011-11-11 23:34:43 +00:00
Object	Move x86-specific tests into X86 folder.	2011-11-01 03:21:48 +00:00
Other
Scripts
TableGen
Transforms	Don't try to loop on iterators that are potentially invalidated inside the loop. Fixes PR11361!	2011-11-12 03:09:12 +00:00
Unit	tests: Rip out a bunch of now unused test code relating to use of llvm-gcc in LLVM tests.	2011-10-27 20:59:26 +00:00
Verifier
CMakeLists.txt	build/cmake: Change to require Python be available.	2011-11-04 23:04:05 +00:00
lit.cfg	Update lit's list of tools.	2011-11-05 16:20:52 +00:00
lit.site.cfg.in	tests: Rip out a bunch of now unused test code relating to use of llvm-gcc in LLVM tests.	2011-10-27 20:59:26 +00:00
Makefile	tests: Rip out a bunch of now unused test code relating to use of llvm-gcc in LLVM tests.	2011-10-27 20:59:26 +00:00
Makefile.tests
site.exp.in	tests: Rip out a bunch of now unused test code relating to use of llvm-gcc in LLVM tests.	2011-10-27 20:59:26 +00:00
TestRunner.sh