fallthrough) in cases where we might fail to rotate an exit to an outer
loop onto the end of the loop chain.

Having *some* rotation, but not performing this rotation, is the primary
fix of thep performance regression with -enable-block-placement for
Olden/em3d (a whopping 30% regression). Still working on reducing the
test case that actually exercises this and the new rotation strategy out
of this code, but I want to check if this regresses other test cases
first as that may indicate it isn't the correct fix.

llvm-svn: 145195

rewrite the known problems section.  Including a short list of individual bugs per target isn't particularly useful.  Link to the target features matrix.

llvm-svn: 145193

blog'izing it.

llvm-svn: 145192

llvm-svn: 145191

llvm-svn: 145190

fails on ppc and arm hosts.

llvm-svn: 145188

was centered around the premise of laying out a loop in a chain, and
then rotating that chain. This is good for preserving contiguous layout,
but bad for actually making sane rotations. In order to keep it safe,
I had to essentially make it impossible to rotate deeply nested loops.
The information needed to correctly reason about a deeply nested loop is
actually available -- *before* we layout the loop. We know the inner
loops are already fused into chains, etc. We lose information the moment
we actually lay out the loop.

The solution was the other alternative for this algorithm I discussed
with Benjamin and some others: rather than rotating the loop
after-the-fact, try to pick a profitable starting block for the loop's
layout, and then use our existing layout logic. I was worried about the
complexity of this "pick" step, but it turns out such complexity is
needed to handle all the important cases I keep teasing out of benchmarks.

This is, I'm afraid, a bit of a work-in-progress. It is still
misbehaving on some likely important cases I'm investigating in Olden.
It also isn't really tested. I'm going to try to craft some interesting
nested-loop test cases, but it's likely to be extremely time consuming
and I don't want to go there until I'm sure I'm testing the correct
behavior. Sadly I can't come up with a way of getting simple, fine
grained test cases for this logic. We need complex loop structures to
even trigger much of it.

llvm-svn: 145183

Original commit message:
Fixed ObjectFile functions:
- getSymbolOffset() renamed as getSymbolFileOffset()
- getSymbolFileOffset(), getSymbolAddress(), getRelocationAddress() returns same result for ELFObjectFile, MachOObjectFile and COFFObjectFile.
- added getRelocationOffset()
- fixed MachOObjectFile::getSymbolSize()
- fixed MachOObjectFile::getSymbolSection()
- fixed MachOObjectFile::getSymbolOffset() for symbols without section data.

llvm-svn: 145182

llvm-svn: 145181

- getSymbolOffset() renamed as getSymbolFileOffset()
- getSymbolFileOffset(), getSymbolAddress(), getRelocationAddress() returns same result for ELFObjectFile, MachOObjectFile and COFFObjectFile.
- added getRelocationOffset()
- fixed MachOObjectFile::getSymbolSize()
- fixed MachOObjectFile::getSymbolSection()
- fixed MachOObjectFile::getSymbolOffset() for symbols without section data.

llvm-svn: 145180

heavily on AnalyzeBranch. That routine doesn't behave as we want given
that rotation occurs mid-way through re-ordering the function. Instead
merely check that there are not unanalyzable branching constructs
present, and then reason about the CFG via successor lists. This
actually simplifies my mental model for all of this as well.

The concrete result is that we now will rotate more loop chains. I've
added a test case from Olden highlighting the effect. There is still
a bit more to do here though in order to regain all of the performance
in Olden.

llvm-svn: 145179

that mainline needs no autoupgrade logic for intrinsics yet, woohoo!

llvm-svn: 145178

I'll work on turning this into something intelligible tomorrow.

llvm-svn: 145177

autoupgrade logic for 2.9 and before.

llvm-svn: 145176

trampoline forms.  Both of these were correct in LLVM 3.0, and we don't
need to support LLVM 2.9 and earlier in mainline.

llvm-svn: 145174

llvm-svn: 145173

remove asmparsing and documentation support for "volatile load", which was only produced by LLVM 2.9 and earlier.  LLVM 3.0 and later prefers "load volatile".

llvm-svn: 145172

Upgrade syntax of tests using volatile instructions to use 'load volatile' instead of 'volatile load', which is archaic.

llvm-svn: 145171

llvm-svn: 145170

I think this is the last of autoupgrade that can be removed in 3.1.
Can the atomic upgrade stuff also go?

llvm-svn: 145169

llvm-svn: 145167

LLVM 3.0 and later.

llvm-svn: 145165

llvm-svn: 145164

llvm-svn: 145163

These instructions are not generated by the backend yet, this will come in a later commit.

llvm-svn: 145161

Removing that buildbot would be a better solution, but this is at least
a temporary workaround.

llvm-svn: 145160

Fix a couple of 80-column violations.

llvm-svn: 145159

pass. This is designed to achieve one of the important optimizations
that the old code placement pass did, but more simply.

This is a somewhat rough and *very* conservative version of the
transform. We could get a lot fancier here if there are profitable cases
to do so. In particular, this only looks for a single pattern, it
insists that the loop backedge being rotated away is the last backedge
in the chain, and it doesn't provide any means of doing better in-loop
placement due to the rotation. However, it appears that it will handle
the important loops I am finding in the LLVM test suite.

llvm-svn: 145158

llvm-svn: 145157

llvm-svn: 145154

Merge 128-bit and 256-bit X86ISD node types for VPERMILPS and VPERMILPD. Simplify some shuffle lowering code since V1 can never be UNDEF due to canonalizing that occurs when shuffle nodes are created.

llvm-svn: 145153

llvm-svn: 145152

Collapse X86ISD node types for PUNPCKH*, PUNPCKL*, UNPCKLP*, and UNPCKHP* to not be type specific. Now we just have integer high and low and floating point high and low. Pattern matching will choose the correct instruction based on the vector type.

llvm-svn: 145148

llvm-svn: 145145

llvm-svn: 145144

for adding other tests.

llvm-svn: 145143

was returning incorrect values in rare cases, and incorrectly marking
exact conversions as inexact in some more common cases. Fixes PR11406, and a
missed optimization in test/CodeGen/X86/fp-stack-O0.ll.

llvm-svn: 145141

llvm-svn: 145138

I don't see how the project is using LLVM and we really can't list every user of
the clang analyzer. Sorry.

llvm-svn: 145137

llvm-svn: 145136