Owen Anderson a04a0649e1 Completely rework the datastructure GVN uses to represent the value number to leader mapping. Previously, ... this was a tree of hashtables, and a query recursed into the table for the immediate dominator ad infinitum if the initial lookup failed. This led to really bad performance on tall, narrow CFGs. We can instead replace it with what is conceptually a multimap of value numbers to leaders (actually represented by a hashtable with a list of Value*'s as the value type), and then determine which leader from that set to use very cheaply thanks to the DFS numberings maintained by DominatorTree. Because there are typically few duplicates of a given value, this scan tends to be quite fast. Additionally, we use a custom linked list and BumpPtr allocation to avoid any unnecessary allocation in representing the value-side of the multimap. This change brings with it a 15% (!) improvement in the total running time of GVN on 403.gcc, which I think is pretty good considering that includes all the "real work" being done by MemDep as well. The one downside to this approach is that we can no longer use GVN to perform simple conditional progation, but that seems like an acceptable loss since we now have LVI and CorrelatedValuePropagation to pick up the slack. If you see conditional propagation that's not happening, please file bugs against LVI or CVP. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119714 91177308-0d34-0410-b5e6-96231b3b80d8		2010-11-18 18:32:40 +00:00
..
Analysis	Delete unneeded ssp attributes.	2010-11-11 21:08:46 +00:00
Archive
Assembler
Bindings/Ocaml
Bitcode	Testcase for PR8494 (invalid bitcode crashing the bitcode reader).	2010-10-28 15:57:30 +00:00
BugPoint
CodeGen	Change CodeGen to use .loc directives. This produces a lot more readable output	2010-11-18 02:04:25 +00:00
DebugInfo	Change CodeGen to use .loc directives. This produces a lot more readable output	2010-11-18 02:04:25 +00:00
ExecutionEngine	lli: Switch to using ParseIRFile, for consistency with other LLVM tools.	2010-11-13 00:28:01 +00:00
Feature
FrontendAda
FrontendC	Test for llvm-gcc patch 119392.	2010-11-16 21:57:15 +00:00
FrontendC++
FrontendFortran
FrontendObjC
FrontendObjC++	Temporarily revert r117079; it broke a tester. Radar 6635085.	2010-10-22 18:44:22 +00:00
Integer
lib
Linker	Fix PR8300 by remembering to keep the bitcast in all cases.	2010-10-19 02:02:57 +00:00
LLVMC	Remove -llvmc-temp-hack from tblgen.	2010-10-23 07:32:53 +00:00
MC	Try again at providing Thumb2 encodings for basic multiplication operators.	2010-11-18 01:08:42 +00:00
Other	Make BasicAliasAnalysis a normal AliasAnalysis implementation which	2010-10-18 18:04:47 +00:00
Scripts	test/Scripts/macho-dump: Make hack for Python-2.4. [PR7995]	2010-10-29 01:14:16 +00:00
TableGen
Transforms	Completely rework the datastructure GVN uses to represent the value number to leader mapping. Previously,	2010-11-18 18:32:40 +00:00
Unit
Verifier
CMakeLists.txt	CMake: Add the new option "LLVM_LIT_ARGS".	2010-11-11 04:09:35 +00:00
lit.cfg
lit.site.cfg.in
Makefile	test/Makefile: Force lit -j1 on Cygwin.	2010-10-22 09:40:37 +00:00
Makefile.tests
site.exp.in
TestRunner.sh