aggressively. There are lots of dire warnings about this being expensive
that seem to predate switching to the TrackingVH-based value remapper
that is automatically updated on RAUW. This makes it easy to not just
prune single-entry PHIs, but to fully simplify PHIs, and to recursively
simplify the newly inlined code to propagate PHINode simplifications.
This introduces a bit of a thorny problem though. We may end up
simplifying a branch condition to a constant when we fold PHINodes, and
we would like to nuke any dead blocks resulting from this so that time
isn't wasted continually analyzing them, but this isn't easy. Deleting
basic blocks *after* they are fully cloned and mapped into the new
function currently requires manually updating the value map. The last
piece of the simplification-during-inlining puzzle will require either
switching to WeakVH mappings or some other piece of refactoring. I've
left a FIXME in the testcase about this.
llvm-svn: 153410
to instead rely on much more generic and powerful instruction
simplification in the function cloner (and thus inliner).
This teaches the pruning function cloner to use instsimplify rather than
just the constant folder to fold values during cloning. This can
simplify a large number of things that constant folding alone cannot
begin to touch. For example, it will realize that 'or' and 'and'
instructions with certain constant operands actually become constants
regardless of what their other operand is. It also can thread back
through the caller to perform simplifications that are only possible by
looking up a few levels. In particular, GEPs and pointer testing tend to
fold much more heavily with this change.
This should (in some cases) have a positive impact on compile times with
optimizations on because the inliner itself will simply avoid cloning
a great deal of code. It already attempted to prune proven-dead code,
but now it will be use the stronger simplifications to prove more code
dead.
llvm-svn: 153403
fire if anything ever invalidates the assumption of a terminator
instruction being unchanged throughout the routine.
I've convinced myself that the current definition of simplification
precludes such a transformation, so I think getting some asserts
coverage that we don't violate this agreement is sufficient to make this
code safe for the foreseeable future.
Comments to the contrary or other suggestions are of course welcome. =]
The bots are now happy with this code though, so it appears the bug here
has indeed been fixed.
llvm-svn: 153401
list. This is a bad idea. ;] I'm hopeful this is the bug that's showing
up with the MSVC bots, but we'll see.
It is definitely unnecessary. InstSimplify won't do anything to
a terminator instruction, we don't need to even include it in the
iteration range. We can also skip the now dead terminator check,
although I've made it an assert to help document that this is an
important invariant.
I'm still a bit queasy about this because there is an implicit
assumption that the terminator instruction cannot be RAUW'ed by the
simplification code. While that appears to be true at the moment, I see
no guarantee that would ensure it remains true in the future. I'm
looking at the cleanest way to solve that...
llvm-svn: 153399
bit simpler by handling a common case explicitly.
Also, refactor the implementation to use a worklist based walk of the
recursive users, rather than trying to use value handles to detect and
recover from RAUWs during the recursive descent. This fixes a very
subtle bug in the previous implementation where degenerate control flow
structures could cause mutually recursive instructions (PHI nodes) to
collapse in just such a way that From became equal to To after some
amount of recursion. At that point, we hit the inf-loop that the assert
at the top attempted to guard against. This problem is defined away when
not using value handles in this manner. There are lots of comments
claiming that the WeakVH will protect against just this sort of error,
but they're not accurate about the actual implementation of WeakVHs,
which do still track RAUWs.
I don't have any test case for the bug this fixes because it requires
running the recursive simplification on unreachable phi nodes. I've no
way to either run this or easily write an input that triggers it. It was
found when using instruction simplification inside the inliner when
running over the nightly test-suite.
llvm-svn: 153393
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
Only record IVUsers that are dominated by simplified loop
headers. Otherwise SCEVExpander will crash while looking for a
preheader.
I previously tried to work around this in LSR itself, but that was
insufficient. This way, LSR can continue to run if some uses are not
in simple loops, as long as we don't attempt to analyze those users.
Fixes <rdar://problem/11049788> Segmentation fault: 11 in LoopStrengthReduce
llvm-svn: 152892
Renamed methods caseBegin, caseEnd and caseDefault with case_begin, case_end, and case_default.
Added some notes relative to case iterators.
llvm-svn: 152532
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120130/136146.html
Implemented CaseIterator and it solves almost all described issues: we don't need to mix operand/case/successor indexing anymore. Base iterator class is implemented as a template since it may be initialized either from "const SwitchInst*" or from "SwitchInst*".
ConstCaseIt is just a read-only iterator.
CaseIt is read-write iterator; it allows to change case successor and case value.
Usage of iterator allows totally remove resolveXXXX methods. All indexing convertions done automatically inside the iterator's getters.
Main way of iterator usage looks like this:
SwitchInst *SI = ... // intialize it somehow
for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); i != e; ++i) {
BasicBlock *BB = i.getCaseSuccessor();
ConstantInt *V = i.getCaseValue();
// Do something.
}
If you want to convert case number to TerminatorInst successor index, just use getSuccessorIndex iterator's method.
If you want initialize iterator from TerminatorInst successor index, use CaseIt::fromSuccessorIndex(...) method.
There are also related changes in llvm-clients: klee and clang.
llvm-svn: 152297
are optimization hints, but at -O0 we're not optimizing. This becomes a problem
when the alwaysinline attribute is abused.
rdar://10921594
llvm-svn: 151429
The purpose of refactoring is to hide operand roles from SwitchInst user (programmer). If you want to play with operands directly, probably you will need lower level methods than SwitchInst ones (TerminatorInst or may be User). After this patch we can reorganize SwitchInst operands and successors as we want.
What was done:
1. Changed semantics of index inside the getCaseValue method:
getCaseValue(0) means "get first case", not a condition. Use getCondition() if you want to resolve the condition. I propose don't mix SwitchInst case indexing with low level indexing (TI successors indexing, User's operands indexing), since it may be dangerous.
2. By the same reason findCaseValue(ConstantInt*) returns actual number of case value. 0 means first case, not default. If there is no case with given value, ErrorIndex will returned.
3. Added getCaseSuccessor method. I propose to avoid usage of TerminatorInst::getSuccessor if you want to resolve case successor BB. Use getCaseSuccessor instead, since internal SwitchInst organization of operands/successors is hidden and may be changed in any moment.
4. Added resolveSuccessorIndex and resolveCaseIndex. The main purpose of these methods is to see how case successors are really mapped in TerminatorInst.
4.1 "resolveSuccessorIndex" was created if you need to level down from SwitchInst to TerminatorInst. It returns TerminatorInst's successor index for given case successor.
4.2 "resolveCaseIndex" converts low level successors index to case index that curresponds to the given successor.
Note: There are also related compatability fix patches for dragonegg, klee, llvm-gcc-4.0, llvm-gcc-4.2, safecode, clang.
llvm-svn: 149481
present in the bottom of the CFG triangle, as the transformation isn't
ever valuable if the branch can't be eliminated.
Also, unify some heuristics between SimplifyCFG's multiple
if-converters, for consistency.
This fixes rdar://10627242.
llvm-svn: 147630
code can incorrectly move the load across a store. This never
happens in practice today, but only because the current
heuristics accidentally preclude it.
llvm-svn: 147623
into Analysis as a standalone function, since there's no need for
it to be in VMCore. Also, update it to use isKnownNonZero and
other goodies available in Analysis, making it more precise,
enabling more aggressive optimization.
llvm-svn: 146610
Patch by Brendon Cahoon!
This extends the existing LoopUnroll and LoopUnrollPass. Brendon
measured no regressions in the llvm test suite with -unroll-runtime
enabled. This implementation works by using the existing loop
unrolling code to unroll the loop by a power-of-two (default 8). It
generates an if-then-else sequence of code prior to the loop to
execute the extra iterations before entering the unrolled loop.
llvm-svn: 146245
- Walking over pred_begin/pred_end is an expensive operation.
- PHINodes contain a value for each predecessor anyway.
- While it may look like we used to save a few iterations with the set,
be aware that getIncomingValueForBlock does a linear search on
the values of the phi node.
- Another -5% on ARMDisassembler.cpp (Release build). This was the last
entry in the profile that was obviously wasting time.
llvm-svn: 145937
- Calling getUser in a loop is much more expensive than iterating over a few instructions.
- Use it instead of the open-coded loop in AddrModeMatcher.
- 5% speedup on ARMDisassembler.cpp Release builds.
llvm-svn: 145810
The callee is usually smaller than the caller, too. This reduces the compile
time of ARMDisassembler.cpp by 32% (Release build). It still takes ages to
compile though.
llvm-svn: 145690
weak variable are compiled by different compilers, such as GCC and LLVM, while
LLVM may increase the alignment to the preferred alignment there is no reason to
think that GCC will use anything more than the ABI alignment. Since it is the
GCC version that might end up in the final program (as the linkage is weak), it
is wrong to increase the alignment of loads from the global up to the preferred
alignment as the alignment might only be the ABI alignment.
Increasing alignment up to the ABI alignment might be OK, but I'm not totally
convinced that it is. It seems better to just leave the alignment of weak
globals alone.
llvm-svn: 145413
The right way to check for a binary operation is
cast<BinaryOperator>. The original check: cast<Instruction> &&
numOperands() == 2 would match phi "instructions", leading to an
infinite loop in extreme corner case: a useless phi with operands
[self, constant] that prior optimization passes failed to remove,
being used in the loop by another useless phi, in turn being used by an
lshr or udiv.
Fixes PR11350: runaway iteration assertion.
llvm-svn: 144935
instructions.
This doesn't introduce any optimizations we weren't doing before (except
potentially due to pass ordering issues), now passes will eliminate them sooner
as part of their own cleanups.
llvm-svn: 142787
promoting allocas to preferred alignments that exceed the natural
alignment. This avoids some potentially expensive dynamic stack realignments.
The natural stack alignment is set in target data strings via the "S<size>"
option. Size is in bits and must be a multiple of 8. The natural stack alignment
defaults to "unspecified" (represented by a zero value), and the "unspecified"
value does not prevent any alignment promotions. Target maintainers that care
about avoiding promotions should explicitly add the "S<size>" option to their
target data strings.
llvm-svn: 141599
This handles the case in which LSR rewrites an IV user that is a phi and
splits critical edges originating from a switch.
Fixes <rdar://problem/6453893> LSR is not splitting edges "nicely"
llvm-svn: 141059
extract the landing pad block. Otherwise, there will be a situation where the
invoke's unwind edge lands on a non-landing pad.
We also forbid the user from extracting the landing pad block by itself. Again,
this is not a valid transformation.
llvm-svn: 140083
In theory this could be extended to other instructions, eg. division by zero, but it's likely that it will "miscompile" some code because people depend on div by zero not trapping. NULL pointer dereference usually leads to a crash so we should be on the safe side.
This shrinks the size of a Release clang by 16k on x86_64.
llvm-svn: 138618
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
SplitLandingPadPredecessors is similar to SplitBlockPredecessors in that it
splits the current block and attaches a set of predecessors to the new basic
block. However, it differs from SplitBlockPredecessors in that it's specifically
designed to handle landing pad blocks.
Two new basic blocks are created: one that is has the vector of predecessors as
its predecessors and one that has the remaining predecessors as its
predecessors. Those two new blocks then receive a cloned copy of the landingpad
instruction from the original block. The landingpad instructions are joined in a
PHI, etc. Like SplitBlockPredecessors, it updates the LLVM IR, AliasAnalysis,
DominatorTree, DominanceFrontier, LoopInfo, and LCCSA analyses.
llvm-svn: 138014
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
This commit includes a mention of the landingpad instruction, but it's not
changing the behavior around it. I think the current behavior is correct,
though. Bill, can you double-check that?
llvm-svn: 137691
This builds off of the current scheme, but instead of llvm.eh.exception and
llvm.eh.selector, it uses the landingpad instruction. And instead of
llvm.eh.resume, it uses the resume instruction.
Because of the invariants in the landing pad instruction, a lot of code that's
currently needed to find the appropriate intrinsic calls for an invoke
instruction won't be needed once we go to the new EH scheme. The "FIXME"s tell
us what to remove after we switch.
llvm-svn: 137576
based on ScalarEvolution without changing the induction variable phis.
This utility is the main tool of IndVarSimplifyPass, but the pass also
restructures induction variables in strange ways that are sensitive to
pass ordering. This provides a way for other loop passes to simplify
new uses of induction variables created during transformation. The
utility may be used by any pass that preserves ScalarEvolution. Soon
LoopUnroll will use it.
The net effect in this checkin is to cleanup the IndVarSimplify pass
by factoring out the SimplifyIndVar algorithm into a standalone utility.
llvm-svn: 137197
These are not individual bug fixes. I had to rewrite a good chunk of
the unroller to make it sane. I think it was getting lucky on trivial
completely unrolled loops with no early exits. I included some fairly
simple unit tests for partial unrolling. I didn't do much stress
testing, so it may not be perfect, but should be usable now.
llvm-svn: 137190
The 'unwind' instruction was acting essentially as a placeholder, because it
would be replaced at the end of this function by a branch to the "unwind
handler". The 'unwind' instruction is going away, so use 'unreachable' instead,
which serves the same purpose as a placeholder.
llvm-svn: 137098
inlined variable, based on the discussion in PR10542.
This explodes the runtime of several passes down the pipeline due to
a large number of "copies" remaining live across a large function. This
only shows up with both debug and opt, but when it does it creates
a many-minute compile when self-hosting LLVM+Clang. There are several
other cases that show these types of regressions.
All of this is tracked in PR10542, and progress is being made on fixing
the issue. Once its addressed, the re-instated, but until then this
restores the performance for self-hosting and other opt+debug builds.
Devang, let me know if this causes any trouble, or impedes fixing it in
any way, and thanks for working on this!
llvm-svn: 136953
specified in the same file that the library itself is created. This is
more idiomatic for CMake builds, and also allows us to correctly specify
dependencies that are missed due to bugs in the GenLibDeps perl script,
or change from compiler to compiler. On Linux, this returns CMake to
a place where it can relably rebuild several targets of LLVM.
I have tried not to change the dependencies from the ones in the current
auto-generated file. The only places I've really diverged are in places
where I was seeing link failures, and added a dependency. The goal of
this patch is not to start changing the dependencies, merely to move
them into the correct location, and an explicit form that we can control
and change when necessary.
This also removes a serialization point in the build because we don't
have to scan all the libraries before we begin building various tools.
We no longer have a step of the build that regenerates a file inside the
source tree. A few other associated cleanups fall out of this.
This isn't really finished yet though. After talking to dgregor he urged
switching to a single CMake macro to construct libraries with both
sources and dependencies in the arguments. Migrating from the two macros
to that style will be a follow-up patch.
Also, llvm-config is still generated with GenLibDeps.pl, which means it
still has slightly buggy dependencies. The internal CMake
'llvm-config-like' macro uses the correct explicitly specified
dependencies however. A future patch will switch llvm-config generation
(when using CMake) to be based on these deps as well.
This may well break Windows. I'm getting a machine set up now to dig
into any failures there. If anyone can chime in with problems they see
or ideas of how to solve them for Windows, much appreciated.
llvm-svn: 136433
The new EH is more simple in many respects. Mainly, we don't have to worry about
the "llvm.eh.exception" and "llvm.eh.selector" calls being in weird places.
llvm-svn: 136339
This takes the new 'resume' instruction and turns it into a direct jump to the
caller's landing pad code. The caller's landingpad instruction is merged with
the landingpad instructions of the callee. This is a bit rough and makes some
assumptions in how the code works. But it passes a simple test.
llvm-svn: 136313
an assert on Darwin llvm-gcc builds.
Assertion failed: (castIsValid(op, S, Ty) && "Invalid cast!"), function Create, file /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/build.llvm-gcc-i386-darwin9-RA/llvm.src/lib/VMCore/Instructions.cpp, li\
ne 2067.
etc.
http://smooshlab.apple.com:8013/builders/llvm-gcc-i386-darwin9-RA/builds/2354
--- Reverse-merging r134893 into '.':
U include/llvm/Target/TargetData.h
U include/llvm/DerivedTypes.h
U tools/bugpoint/ExtractFunction.cpp
U unittests/Support/TypeBuilderTest.cpp
U lib/Target/ARM/ARMGlobalMerge.cpp
U lib/Target/TargetData.cpp
U lib/VMCore/Constants.cpp
U lib/VMCore/Type.cpp
U lib/VMCore/Core.cpp
U lib/Transforms/Utils/CodeExtractor.cpp
U lib/Transforms/Instrumentation/ProfilingUtils.cpp
U lib/Transforms/IPO/DeadArgumentElimination.cpp
U lib/CodeGen/SjLjEHPrepare.cpp
--- Reverse-merging r134888 into '.':
G include/llvm/DerivedTypes.h
U include/llvm/Support/TypeBuilder.h
U include/llvm/Intrinsics.h
U unittests/Analysis/ScalarEvolutionTest.cpp
U unittests/ExecutionEngine/JIT/JITTest.cpp
U unittests/ExecutionEngine/JIT/JITMemoryManagerTest.cpp
U unittests/VMCore/PassManagerTest.cpp
G unittests/Support/TypeBuilderTest.cpp
U lib/Target/MBlaze/MBlazeIntrinsicInfo.cpp
U lib/Target/Blackfin/BlackfinIntrinsicInfo.cpp
U lib/VMCore/IRBuilder.cpp
G lib/VMCore/Type.cpp
U lib/VMCore/Function.cpp
G lib/VMCore/Core.cpp
U lib/VMCore/Module.cpp
U lib/AsmParser/LLParser.cpp
U lib/Transforms/Utils/CloneFunction.cpp
G lib/Transforms/Utils/CodeExtractor.cpp
U lib/Transforms/Utils/InlineFunction.cpp
U lib/Transforms/Instrumentation/GCOVProfiling.cpp
U lib/Transforms/Scalar/ObjCARC.cpp
U lib/Transforms/Scalar/SimplifyLibCalls.cpp
U lib/Transforms/Scalar/MemCpyOptimizer.cpp
G lib/Transforms/IPO/DeadArgumentElimination.cpp
U lib/Transforms/IPO/ArgumentPromotion.cpp
U lib/Transforms/InstCombine/InstCombineCompares.cpp
U lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
U lib/Transforms/InstCombine/InstCombineCalls.cpp
U lib/CodeGen/DwarfEHPrepare.cpp
U lib/CodeGen/IntrinsicLowering.cpp
U lib/Bitcode/Reader/BitcodeReader.cpp
llvm-svn: 134949
patch brings numerous advantages to LLVM. One way to look at it
is through diffstat:
109 files changed, 3005 insertions(+), 5906 deletions(-)
Removing almost 3K lines of code is a good thing. Other advantages
include:
1. Value::getType() is a simple load that can be CSE'd, not a mutating
union-find operation.
2. Types a uniqued and never move once created, defining away PATypeHolder.
3. Structs can be "named" now, and their name is part of the identity that
uniques them. This means that the compiler doesn't merge them structurally
which makes the IR much less confusing.
4. Now that there is no way to get a cycle in a type graph without a named
struct type, "upreferences" go away.
5. Type refinement is completely gone, which should make LTO much MUCH faster
in some common cases with C++ code.
6. Types are now generally immutable, so we can use "Type *" instead
"const Type *" everywhere.
Downsides of this patch are that it removes some functions from the C API,
so people using those will have to upgrade to (not yet added) new API.
"LLVM 3.0" is the right time to do this.
There are still some cleanups pending after this, this patch is large enough
as-is.
llvm-svn: 134829
"Reinstate r133435 and r133449 (reverted in r133499) now that the clang
self-hosted build failure has been fixed (r133512)."
Due to some additional warnings.
llvm-svn: 133700
Change PHINodes to store simple pointers to their incoming basic blocks,
instead of full-blown Uses.
Note that this loses an optimization in SplitCriticalEdge(), because we
can no longer walk the use list of a BasicBlock to find phi nodes. See
the comment I removed starting "However, the foreach loop is slow for
blocks with lots of predecessors".
Extend replaceAllUsesWith() on a BasicBlock to also update any phi
nodes in the block's successors. This mimics what would have happened
when PHINodes were proper Users of their incoming blocks. (Note that
this only works if OldBB->replaceAllUsesWith(NewBB) is called when
OldBB still has a terminator instruction, so it still has some
successors.)
llvm-svn: 133435
In cases such as the attached test, where the case value for a switch
destination is used in a phi node that follows the destination, it
might be better to replace that value with the condition value of the
switch, so that more blocks can be folded away with
TryToSimplifyUncondBranchFromEmptyBlock because there are less
conflicts in the phi node.
llvm-svn: 133344
intrinsics. In fact, we'll optimize a bitcast to that when possible. Detect it
when looking for the lifetime intrinsics.
No test case, noticed by inspection.
llvm-svn: 132906
pad, separating the exception and selector calls from the new lpad. Teaching
it not to do that, or to properly adjust the CFG afterwards, is out of
scope because it would require the other edges to the landing pad to be split
as well (effectively). Instead, just recover from the most likely cases
during inlining. The best long-term solution is to change the exception
representation and commit to either requiring or not requiring the more
complex edge-splitting logic; this is just a shorter-term hack.
llvm-svn: 132799
then we don't want to set the destination in the indirect branch to the
destination. This is because the indirect branch needs its destinations to have
had their block addresses taken. This isn't so of the new critical edge that's
split during this process. If it turns out that the destination block has only
one predecessor, and that being a BB with an indirect branch, then it won't be
marked as 'used' and may be removed.
PR10072
llvm-svn: 132638
transformed by the inliner into a branch to the enclosing landing pad
(when inlined through an invoke). If not so optimized, it is lowered
DWARF EH preparation into a call to _Unwind_Resume (or _Unwind_SjLj_Resume
as appropriate). Its chief advantage is that it takes both the
exception value and the selector value as arguments, meaning that there
is zero effort in recovering these; however, the frontend is required
to pass these down, which is not actually particularly difficult.
Also document the behavior of landing pads a bit better, and make it
clearer that it's okay that personality functions don't always land at
landing pads. This is just a fact of life. Don't write optimizations that
rely on pushing things over an unwind edge.
llvm-svn: 132253
- the selector for the landing pad must provide all available information
about the handlers, filters, and cleanups within that landing pad
- calls to _Unwind_Resume must be converted to branches to the enclosing
lpad so as to avoid re-entering the unwinder when the lpad claimed it
was going to handle the exception in some way
This is quite specific to libUnwind-based unwinding. In an effort to not
interfere too badly with other unwinders, and with existing hacks in frontends,
this only triggers on _Unwind_Resume (not _Unwind_Resume_or_Rethrow) and does
nothing with selectors if it cannot find a selector call for either lpad.
llvm-svn: 132200
I also changed -simplifycfg, -jump-threading and -codegenprepare to use this to produce slightly better code without any extra cleanup passes (AFAICT this was the only place in -simplifycfg where now-dead conditions of replaced terminators weren't being cleaned up). The only other user of this function is -sccp, but I didn't read that thoroughly enough to figure out whether it might be holding pointers to instructions that could be deleted by this.
llvm-svn: 131855
instruction around, reducing work.
Greatly simplify handling of debug instructions. There is no need to
build up a vector of them and then move them into the one predecessor
if we're processing a block. Instead just rescan the block and *copy*
them into the pred. If a block gets merged into multiple preds, this
will retain more debug info.
llvm-svn: 129502
after the given instruction; make sure to handle that case correctly.
(It's difficult to trigger; the included testcase involves a dead
block, but I don't think that's a requirement.)
While I'm here, get rid of the unnecessary warning about
SimplifyInstructionsInBlock, since it should work correctly as far as I know.
llvm-svn: 128782
reachable uses, but there still might be uses in dead blocks. Use the
standard solution of replacing all the uses with undef. This is
a rare case because it's very sensitive to phase ordering in SimplifyCFG.
llvm-svn: 127299
Yes, there are other types than i8* and GEPs on them can produce an add+multiply.
We don't consider that cheap enough to be speculatively executed.
llvm-svn: 126481
itself without going via a phi node then we could return false here in
spite of making a change. Also, tweak the comment because this method
can (and always could) return true without deleting the original phi node.
For example, if the phi node was used by a read-only invoke instruction
which is used by another phi node phi2 which is only used by and only uses
the invoke, then phi2 would be deleted but not the invoke instruction and
not the original phi node.
llvm-svn: 126129
should be that if the phi is used by a side-effect free instruction with
no uses then the phi and the instruction now get zapped (checked by the
unittest).
llvm-svn: 126124
test for that. With this change, test/CodeGen/X86/codegen-dce.ll no longer finds
any instructions to DCE, so delete the test.
Also renamed J and JP to I and IP in RecursivelyDeleteDeadPHINode.
llvm-svn: 126088
This is part of a futile attempt to not "break" bizzaro
code like this:
l1:
printf("l1: %p\n", &&l1);
++x;
if( x < 3 ) goto l1;
Previously we'd fold &&l1 to 1, which is fine per our semantics
but not helpful to the user.
llvm-svn: 125827
This makes the job of the later optzn passes easier, allowing the vast amount of
icmp transforms to chew on it.
We transform 840 switches in gcc.c, leading to a 16k byte shrink of the resulting
binary on i386-linux.
The testcase from README.txt now compiles into
decl %edi
cmpl $3, %edi
sbbl %eax, %eax
andl $1, %eax
ret
llvm-svn: 124724
checks enabled:
1) Use '<' to compare integers in a comparison function rather than '<='.
2) Use the uniqued set DefBlocks rather than Info.DefiningBlocks to initialize
the priority queue.
The speedup of scalarrepl on test-suite + SPEC2000 + SPEC2006 is a bit less, at
just under 16% rather than 17%.
llvm-svn: 123662
eliminating a potentially quadratic data structure, this also gives a 17%
speedup when running -scalarrepl on test-suite + SPEC2000 + SPEC2006. My initial
experiment gave a greater speedup around 25%, but I moved the dominator tree
level computation from dominator tree construction to PromoteMemToReg.
Since this approach to computing IDFs has a much lower overhead than the old
code using precomputed DFs, it is worth looking at using this new code for the
second scalarrepl pass as well.
llvm-svn: 123609
DT->changeImmediateDominator() trivially ignores identity updates, so there is
really no need for the uniqueing provided by SmallPtrSet.
I expect this to fix PR8954.
llvm-svn: 123286
phi nodes. It is called from MergeBlockIntoPredecessor which is
called from GVN, which claims to preserve these.
I'm skeptical that this is the actual problem behind PR8954, but
this is a stab in the right direction.
llvm-svn: 123222
they all ready do). This removes two dominator recomputations prior to isel,
which is a 1% improvement in total llc time for 403.gcc.
The only potentially suspect thing is making GCStrategy recompute dominators if
it used a custom lowering strategy.
llvm-svn: 123064
1. Take a flags argument instead of a bool. This makes
it more clear to the reader what it is used for.
2. Add a flag that says that "remapping a value not in the
map is ok".
3. Reimplement MapValue to share a bunch of code and be a lot
more efficient. For lookup failures, don't drop null values
into the map.
4. Using the new flag a bunch of code can vaporize in LinkModules
and LoopUnswitch, kill it.
No functionality change.
llvm-svn: 123058
in the PR, the pass could break LCSSA form when inserting preheaders. It probably
would be easy enough to fix this, but since currently we always go into LCSSA form
after running this pass, doing so is not urgent.
llvm-svn: 122695
visit instructions before their uses, since InstructionSimplify does a
better job in that case. All this prompted by Frits van Bommel.
llvm-svn: 122343
it could only be tested indirectly, via instcombine, gvn or some other
pass that makes use of InstructionSimplify, which means that testcases
had to be carefully contrived to dance around any other transformations
that that pass did.
llvm-svn: 122264
argument. The generated alloca has to have at least the alignment of the
byval, if not, the client may be making assumptions that the new alloca won't
satisfy.
llvm-svn: 122234
which is simpler than finding a place to insert in BB.
- Don't perform the 'if condition hoisting' xform on certain
i1 PHIs, as it interferes with switch formation.
This re-fixes "example 7", without breaking the world hopefully.
llvm-svn: 121764
first, it can kick in on blocks whose conditions have been
folded to a constant, even though one of the edges will be
trivially folded.
second, it doesn't clean up the "if diamond" that it just
eliminated away. This is a problem because other simplifycfg
xforms kick in depending on the order of block visitation,
causing pointless work.
llvm-svn: 121762
when simplifying, allowing them to be eagerly turned into switches. This
is the last step required to get "Example 7" from this blog post:
http://blog.regehr.org/archives/320
On X86, we now generate this machine code, which (to my eye) seems better
than the ICC generated code:
_crud: ## @crud
## BB#0: ## %entry
cmpb $33, %dil
jb LBB0_4
## BB#1: ## %switch.early.test
addb $-34, %dil
cmpb $58, %dil
ja LBB0_3
## BB#2: ## %switch.early.test
movzbl %dil, %eax
movabsq $288230376537592865, %rcx ## imm = 0x400000017001421
btq %rax, %rcx
jb LBB0_4
LBB0_3: ## %lor.rhs
xorl %eax, %eax
ret
LBB0_4: ## %lor.end
movl $1, %eax
ret
llvm-svn: 121690
location in simplifycfg. In the old days, SimplifyCFG was never run on
the entry block, so we had to scan over all preds of the BB passed into
simplifycfg to do this xform, now we can just check blocks ending with
a condbranch. This avoids a scan over all preds of every simplified
block, which should be a significant compile-time perf win on functions
with lots of edges. No functionality change.
llvm-svn: 121668
preserves LCSSA form out of ScalarEvolution and into the LoopInfo
class. Use it to check that SimplifyInstruction simplifications
are not breaking LCSSA form. Fixes PR8622.
llvm-svn: 119727
hasConstantValue. I was leery of using SimplifyInstruction
while the IR was still in a half-baked state, which is the
reason for delaying the simplification until the IR is fully
cooked.
llvm-svn: 119494
it isn't unreachable and should not be zapped. The check for the entry block
was missing in one case: a block containing a unwind instruction. While there,
do some small cleanups: "M" is not a great name for a Function* (it would be
more appropriate for a Module*), change it to "Fn"; use Fn in more places.
llvm-svn: 117224
must be called in the pass's constructor. This function uses static dependency declarations to recursively initialize
the pass's dependencies.
Clients that only create passes through the createFooPass() APIs will require no changes. Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.
I have tested this with all standard configurations of clang and llvm-gcc on Darwin. It is possible that there are problems
with the static dependencies that will only be visible with non-standard options. If you encounter any crash in pass
registration/creation, please send the testcase to me directly.
llvm-svn: 116820
perform initialization without static constructors AND without explicit initialization
by the client. For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve. I hope to be able to relax
the latter requirement in the future.
llvm-svn: 116334
I'm sure it is harmless. Original commit message:
If PrototypeValue is erased in the middle of using the SSAUpdator
then the SSAUpdator may access freed memory. Instead, simply pass
in the type and name explicitly, which is all that was used anyway.
llvm-svn: 112810
fix: add a flag to MapValue and friends which indicates whether
any module-level mappings are being made. In the common case of
inlining, no module-level mappings are needed, so MapValue doesn't
need to examine non-function-local metadata, which can be very
expensive in the case of a large module with really deep metadata
(e.g. a large C++ program compiled with -g).
This flag is a little awkward; perhaps eventually it can be moved
into the ClonedCodeInfo class.
llvm-svn: 112190
which does the same thing. This eliminates redundant code and
handles MDNodes better. MDNode linking still doesn't fully
work yet though.
llvm-svn: 111941
that it avoids a lot of unnecessary cloning by avoiding remapping
MDNode cycles when none of the nodes in the cycle actually need to
be remapped. Also it uses the new temporary MDNode mechanism.
llvm-svn: 111922
- Eliminate redundant successors.
- Convert an indirectbr with one successor into a direct branch.
Also, generalize SimplifyCFG to be able to be run on a function entry block.
It knows quite a few simplifications which are applicable to the entry
block, and it only needs a few checks to avoid trouble with the entry block.
llvm-svn: 111060
dependence on DominanceFrontier. Instead, add an explicit DominanceFrontier
pass in StandardPasses.h to ensure that it gets scheduled at the right
time.
Declare that loop unrolling preserves ScalarEvolution, and shuffle some
getAnalysisUsages.
This eliminates one LoopSimplify and one LCCSA run in the standard
compile opts sequence.
llvm-svn: 109413
it *changing* the things it replaces, not just causing them
to drop to null. There is no functionality change yet, but
this is required for a subsequent patch.
llvm-svn: 108414
"bonus" instruction to be speculatively executed. Add a heuristic to
ensure we're not tripping up out-of-order execution by checking that this bonus
instruction only uses values that were already guaranteed to be available.
This allows us to eliminate the short circuit in (x&1)&&(x&2).
llvm-svn: 108351
for an "i" constraint should get lowered; PR 6309. While
this argument was passed around a lot, this is the only
place it was used, so it goes away from a lot of other
places.
llvm-svn: 106893
Chandler Carruth