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Chandler Carruth 595a99573a [unroll] Make the unroll cost analysis terminate deterministically and
reasonably quickly.

I don't have a reduced test case, but for a version of FFMPEG, this
makes the loop unroller start finishing at all (after over 15 minutes of
running, it hadn't terminated for me, no idea if it was a true infloop
or just exponential work).

The key thing here is to check the DeadInstructions set when pulling
things off the worklist. Without this, we would re-walk the user list of
already dead instructions again and again and again. Consider phi nodes
with many, many operands and other patterns.

The other important aspect of this is that because we would keep
re-visiting instructions that were already known dead, we kept adding
their cost savings to this! This would cause our cost savings to be
*insanely* inflated from this.

While I was here, I also rotated the operand walk out of the worklist
loop to make the code easier to read. There is still work to be done to
minimize worklist traffic because we don't de-duplicate operands. This
means we may add the same instruction onto the worklist 1000s of times
if it shows up in 1000s of operansd to a PHI node for example.

Still, with this patch, the ffmpeg testcase I have finishes quickly and
I can't measure the runtime impact of the unroll analysis any more. I'll
probably try to do a few more cleanups to this code, but not sure how
much cleanup I can justify right now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229038 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 03:40:58 +00:00
autoconf Fix some bashims. More information on https://wiki.ubuntu.com/DashAsBinSh. Reported initially on https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=772302 & https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=772301 2015-02-01 14:55:43 +00:00
bindings [OCaml] Add Llvm.build_empty_phi. 2015-02-06 13:42:03 +00:00
cmake Teach llvm_add_library() to find include dirs. 2015-02-10 05:04:37 +00:00
docs Don't promote asynch EH invokes of nounwind functions to calls 2015-02-11 01:23:16 +00:00
examples [Orc] Add a JITSymbol class to the Orc APIs, refactor APIs, update clients. 2015-02-09 01:20:51 +00:00
include IR: Drop never-used defaults for DIBuilder::createTemplate*(), NFC 2015-02-13 03:35:29 +00:00
lib [unroll] Make the unroll cost analysis terminate deterministically and 2015-02-13 03:40:58 +00:00
projects [cmake] Use the external project machinery for libcxxabi so that it can 2014-07-25 10:27:40 +00:00
test [IC] Fix a bug with the instcombine canonicalizing of loads and 2015-02-13 02:30:01 +00:00
tools Add concrete type overloads to PDBSymbol::findChildren(). 2015-02-12 21:09:24 +00:00
unittests Fix the build, I forgot to check that UnitTests still built. 2015-02-13 01:39:22 +00:00
utils AsmWriter/Bitcode: MDExpression 2015-02-13 01:42:09 +00:00
.arcconfig Updated phabricator server. 2014-04-07 03:57:04 +00:00
.clang-format Test commit. 2014-03-02 13:08:46 +00:00
.clang-tidy Enable display of compiler diagnostics in clang-tidy by default. 2014-10-29 17:29:38 +00:00
.gitignore Add one more vim swap file pattern 2015-01-30 21:59:28 +00:00
CMakeLists.txt Revert "Raising minimum required CMake version to 2.8.12.2." 2015-02-09 22:07:49 +00:00
CODE_OWNERS.TXT Assume code ownership for the PS4 to ensure patches get reviewed, per the Developer Policy. 2015-01-28 18:33:39 +00:00
configure Fix some bashims. More information on https://wiki.ubuntu.com/DashAsBinSh. Reported initially on https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=772302 & https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=772301 2015-02-01 14:55:43 +00:00
CREDITS.TXT Rise from the dead and update personal info 2014-08-25 17:51:04 +00:00
LICENSE.TXT Remove projects/sample. 2014-03-12 22:40:22 +00:00
llvm.spec.in Tidy up. s/Low Level Virtual Machine/LLVM/. 2012-01-25 22:00:23 +00:00
LLVMBuild.txt Remove the very substantial, largely unmaintained legacy PGO 2013-10-02 15:42:23 +00:00
Makefile [configure/make] Propagate names of build host tools when making BuildTools 2014-03-25 21:45:41 +00:00
Makefile.common Makefile.common: Update a description, s/Source/SOURCES/ , according to MakefileGuide.html#control-variables . 2012-12-07 01:43:23 +00:00
Makefile.config.in Add a check for misbehaving -Wcomment from gcc-4.7 and add 2014-11-05 00:35:15 +00:00
Makefile.rules Add a check for misbehaving -Wcomment from gcc-4.7 and add 2014-11-05 00:35:15 +00:00
README.txt Revert test commit 2015-02-04 18:46:00 +00:00

Low Level Virtual Machine (LLVM)
================================

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