Commit Graph

144 Commits

Author SHA1 Message Date
Chandler Carruth 73523021d0 [PM] Split DominatorTree into a concrete analysis result object which
can be used by both the new pass manager and the old.

This removes it from any of the virtual mess of the pass interfaces and
lets it derive cleanly from the DominatorTreeBase<> template. In turn,
tons of boilerplate interface can be nuked and it turns into a very
straightforward extension of the base DominatorTree interface.

The old analysis pass is now a simple wrapper. The names and style of
this split should match the split between CallGraph and
CallGraphWrapperPass. All of the users of DominatorTree have been
updated to match using many of the same tricks as with CallGraph. The
goal is that the common type remains the resulting DominatorTree rather
than the pass. This will make subsequent work toward the new pass
manager significantly easier.

Also in numerous places things became cleaner because I switched from
re-running the pass (!!! mid way through some other passes run!!!) to
directly recomputing the domtree.

llvm-svn: 199104
2014-01-13 13:07:17 +00:00
Chandler Carruth 5ad5f15cff [cleanup] Move the Dominators.h and Verifier.h headers into the IR
directory. These passes are already defined in the IR library, and it
doesn't make any sense to have the headers in Analysis.

Long term, I think there is going to be a much better way to divide
these matters. The dominators code should be fully separated into the
abstract graph algorithm and have that put in Support where it becomes
obvious that evn Clang's CFGBlock's can use it. Then the verifier can
manually construct dominance information from the Support-driven
interface while the Analysis library can provide a pass which both
caches, reconstructs, and supports a nice update API.

But those are very long term, and so I don't want to leave the really
confusing structure until that day arrives.

llvm-svn: 199082
2014-01-13 09:26:24 +00:00
Andrew Trick 6796ab424c Reapply r198478 "Fix PR18361: Invalidate LoopDispositions after LoopSimplify hoists things."
Now with a fix for PR18384: ValueHandleBase::ValueIsDeleted.

We need to invalidate SCEV's loop info when we delete a block, even if no values are hoisted.

llvm-svn: 198631
2014-01-06 19:43:14 +00:00
Alp Toker 5e9f3265f8 Revert "Fix PR18361: Invalidate LoopDispositions after LoopSimplify hoists things."
This commit was the source of crasher PR18384:

While deleting: label %for.cond127
An asserting value handle still pointed to this value!
UNREACHABLE executed at llvm/lib/IR/Value.cpp:671!

Reverting to get the builders green, feel free to re-land after fixing up.
(Renato has a handy isolated repro if you need it.)

This reverts commit r198478.

llvm-svn: 198503
2014-01-04 17:00:45 +00:00
Andrew Trick aceac9746d Fix PR18361: Invalidate LoopDispositions after LoopSimplify hoists things.
getSCEV for an ashr instruction creates an intermediate zext
expression when it truncates its operand.

The operand is initially inside the loop, so the narrow zext
expression has a non-loop-invariant loop disposition.

LoopSimplify then runs on an outer loop, hoists the ashr operand, and
properly invalidate the SCEVs that are mapped to value.

The SCEV expression for the ashr is now an AddRec with the hoisted
value as the now loop-invariant start value.

The LoopDisposition of this wide value was properly invalidated during
LoopSimplify.

However, if we later get the ashr SCEV again, we again try to create
the intermediate zext expression. We get the same SCEV that we did
earlier, and it is still cached because it was never mapped to a
Value. When we try to create a new AddRec we abort because we're using
the old non-loop-invariant LoopDisposition.

I don't have a solution for this other than to clear LoopDisposition
when LoopSimplify hoists things.

I think the long-term strategy should be to perform LoopSimplify on
all loops before computing SCEV and before running any loop opts on
individual loops. It's possible we may want to rerun LoopSimplify on
individual loops, but it should rarely do anything, so rarely require
invalidating SCEV.

llvm-svn: 198478
2014-01-04 05:52:49 +00:00
Hal Finkel a969df84ab Rename LoopSimplify.h to LoopUtils.h
As discussed, LoopUtils.h is a better name.

llvm-svn: 182314
2013-05-20 20:46:30 +00:00
Hal Finkel a12d82b421 Expose InsertPreheaderForLoop from LoopSimplify to other passes
Other passes, PPC counter-loop formation for example, also need to add loop
preheaders outside of the regular loop simplification pass. This makes
InsertPreheaderForLoop a global function so that it can be used by other
passes.

No functionality change intended.

llvm-svn: 182299
2013-05-20 16:47:07 +00:00
Chandler Carruth 9fb823bbd4 Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

llvm-svn: 171366
2013-01-02 11:36:10 +00:00
Chandler Carruth ed0881b2a6 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131
2012-12-03 16:50:05 +00:00
Benjamin Kramer 7736085894 LoopSimplify: Preserve DependenceAnalysis.
This is currently true, but may change when DA grows more aggressive caching.
Without this setting it's impossible to use DA from a LoopPass because DA is a
function pass and cannot be properly scheduled in between LoopPasses. The
LoopManager reacts to this with an infinite loop which made this really annoying
to debug.

llvm-svn: 166788
2012-10-26 17:40:50 +00:00
Benjamin Kramer e3d821a466 Fix SCEV cache invalidation in LCSSA and LoopSimplify.
The LoopSimplify bug is pretty harmless because the loop goes from unanalyzable
to analyzable but the LCSSA bug is very nasty. It only comes into play with a
specific order of the LoopPassManager worklist and can cause actual
miscompilations, when a SCEV refers to a value that has been replaced with PHI
node. SCEVExpander may then insert code into the wrong place, either violating
domination or randomly miscompiling stuff.

Comes with an extensive test case reduced from the test-suite with
bugpoint+SCEVValidator.

llvm-svn: 166787
2012-10-26 17:31:43 +00:00
Andrew Trick f7711010e1 LoopSimplify bug fix. Handle indirect loop back edges.
Do not call SplitBlockPredecessors on a loop preheader when one of the
predecessors is an indirectbr. Otherwise, you will hit this assert:
!isa<IndirectBrInst>(Preds[i]->getTerminator()) && "Cannot split an edge from an IndirectBrInst"

llvm-svn: 153134
2012-03-20 21:24:52 +00:00
Andrew Trick bb01cbb312 whitespace
llvm-svn: 153133
2012-03-20 21:24:47 +00:00
Eli Friedman 16ad2905a3 Make loop preheader insertion in LoopSimplify handle the case where the loop header is a landing pad correctly (by splitting the landingpad out of the loop header). Make some adjustments to the rest of LoopSimplify to make it clear that the rest of LoopSimplify isn't making bad assumptions about the presence of landing pads. PR11575.
llvm-svn: 146621
2011-12-15 00:50:34 +00:00
Jakub Staszak f5b32e52db SplitBlockPredecessors uses ArrayRef instead of Data and Size.
llvm-svn: 146277
2011-12-09 21:19:53 +00:00
Chad Rosier c24b86ffbe Propagate TargetLibraryInfo throughout ConstantFolding.cpp and
InstructionSimplify.cpp.  Other fixups as needed.
Part of rdar://10500969

llvm-svn: 145559
2011-12-01 03:08:23 +00:00
Bill Wendling c61f7659ba Intelligently split the landing pad block.
We have to be careful when splitting the landing pad block, because the
landingpad instruction is required to remain as the first non-PHI of an invoke's
unwind edge. To retain this, we split the block into two blocks, moving the
predecessors within the loop to one block and the remaining predecessors to the
other. The landingpad instruction is cloned into the new blocks.

llvm-svn: 138015
2011-08-19 00:09:22 +00:00
Bill Wendling b15d6eb93b Revert r137871. The loop simplify pass should require all exits from a loop that
aren't from an indirect branch need to be dominated by the loop header.

llvm-svn: 137981
2011-08-18 21:10:01 +00:00
Bill Wendling 39257d6b5c Don't optimize the landing pad exit block.
One way to exit the loop is through an unwind edge. However, that may involve
splitting the critical edge of the landing pad, which is non-trivial. Prevent
the transformation from rewriting the landing pad exit loop block.

llvm-svn: 137871
2011-08-17 21:20:43 +00:00
Duncan Sands a41634e307 Silence a bunch (but not all) "variable written but not read" warnings
when building with assertions disabled.

llvm-svn: 137460
2011-08-12 14:54:45 +00:00
Andrew Trick bf69d03382 SCEV: Use AssertingVH to catch dangling BasicBlock* when passes forget
to notify SCEV of a change. Add forgetLoop in a couple of those places.

llvm-svn: 136797
2011-08-03 18:32:11 +00:00
Andrew Trick 9d8c2af257 whitespace
llvm-svn: 136795
2011-08-03 18:28:21 +00:00
Devang Patel 6f7315b0ca Set debug loc for new preheader's terminator.
llvm-svn: 133298
2011-06-17 21:36:44 +00:00
Chris Lattner 0ab5e2cded Fix a ton of comment typos found by codespell. Patch by
Luis Felipe Strano Moraes!

llvm-svn: 129558
2011-04-15 05:18:47 +00:00
Jay Foad 52131344a2 Remove PHINode::reserveOperandSpace(). Instead, add a parameter to
PHINode::Create() giving the (known or expected) number of operands.

llvm-svn: 128537
2011-03-30 11:28:46 +00:00