Commit Graph

399 Commits

Author SHA1 Message Date
Duncan Sands
a28bd85aa9 Make GVN's propagateEquality non-recursive. No intended functionality change.
The modifications are a lot more trivial than they appear to be in the diff!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154174 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-06 15:31:09 +00:00
Jakob Stoklund Olesen
41e2073f62 Don't PRE compares.
CodeGenPrepare sinks compare instructions down to their uses to prevent
live flags and predicate registers across basic blocks.

PRE of a compare instruction prevents that, forcing the i1 compare
result into a general purpose register.  That is usually more expensive
than the redundant compare PRE was trying to eliminate in the first
place.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153657 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-29 17:22:39 +00:00
Duncan Sands
e959f7e17f When propagating equalities, eg replacing A with B in every basic block
dominated by Root, check that B is available throughout the scope.  This
is obviously true (famous last words?) given the current logic, but the
check may be helpful if more complicated reasoning is added one day.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153323 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-23 08:45:52 +00:00
Stepan Dyatkovskiy
3d3abe0852 llvm::SwitchInst
Renamed methods caseBegin, caseEnd and caseDefault with case_begin, case_end, and case_default.
Added some notes relative to case iterators.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152532 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-11 06:09:17 +00:00
Stepan Dyatkovskiy
c10fa6c801 Taken into account Duncan's comments for r149481 dated by 2nd Feb 2012:
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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152297 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-08 07:06:20 +00:00
Duncan Sands
8d12f72c11 This is not a common case, in fact it never happens!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152027 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-05 12:23:00 +00:00
Chandler Carruth
16003d0c0c Replace the ad-hoc hashing in GVN with the new hashing infrastructure.
This implicitly fixes a nasty bug in the GVN hashing (that thankfully
could only manifest as a performance bug): actually include the opcode
in the hash. The old code started the hash off with the opcode, but then
overwrote it with the type pointer.

Since this is likely to be pretty hot (GVN being already pretty
expensive) I've included a micro-optimization to just not bother with
the varargs hashing if they aren't present. I can't measure any change
in GVN performance due to this, even with a big test case like Duncan's
sqlite one. Everything I see is in the noise floor. That said, this
closes a loop hole for a potential scaling problem due to collisions if
the opcode were the differentiating aspect of the expression.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152025 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-05 11:29:54 +00:00
Duncan Sands
190e5a3314 Nick pointed out on IRC that GVN's propagateEquality wasn't propagating
equalities into phi node operands for which the equality is known to
hold in the incoming basic block.  That's because replaceAllDominatedUsesWith
wasn't handling phi nodes correctly in general (that this didn't give wrong
results was just luck: the specific way GVN uses replaceAllDominatedUsesWith
precluded wrong changes to phi nodes).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152006 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-04 13:25:19 +00:00
Duncan Sands
2b4f491045 Have GVN also do condition propagation when the right-hand side is not
a constant.  This fixes PR1768.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151713 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-29 11:12:03 +00:00
Duncan Sands
768ada611b Micro-optimization, no functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151524 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-27 12:11:41 +00:00
Duncan Sands
5583e30818 The value numbering function is recursive, so it is possible for multiple new
value numbers to be assigned when calculating any particular value number.
Enhance the logic that detects new value numbers to take this into account,
for a tiny compile time speedup.  Fix a comment typo while there.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151522 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-27 09:54:35 +00:00
Duncan Sands
669011f50b When performing a conditional branch depending on the value of a comparison
%cmp (eg: A==B) we already replace %cmp with "true" under the true edge, and
with "false" under the false edge.  This change enhances this to replace the
negated compare (A!=B) with "false" under the true edge and "true" under the
false edge.  Reported to improve perlbench results by 1%.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151517 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-27 08:14:30 +00:00
Duncan Sands
e170c76ccd Teach GVN that x+y is the same as y+x and that x<y is the same as y>x.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151365 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-24 15:16:31 +00:00
Duncan Sands
8c160548ce Use Use::set rather than finding the operand number of the use
and setting that.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150074 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-08 14:10:53 +00:00
Duncan Sands
c4fd448712 Neaten up this method. Check that if there is only one
predecessor then it's Src.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149843 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-05 19:43:37 +00:00
Duncan Sands
87ba3f122b Fix a thinko pointed out by Eli and the buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149839 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-05 18:56:50 +00:00
Duncan Sands
33756f96d7 Reduce the number of dom queries made by GVN's conditional propagation
logic by half: isOnlyReachableViaThisEdge was trying to be clever and
handle the case of a branch to a basic block which is contained in a
loop.  This costs a domtree lookup and is completely useless due to
GVN's position in the pass pipeline: all loops have preheaders at this
point, which means it is enough for isOnlyReachableViaThisEdge to check
that Dst has only one predecessor.  (I checked this theoretical argument
by running over the entire nightly testsuite, and indeed it is so!).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149838 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-05 18:25:50 +00:00
Duncan Sands
68e20223a7 Reduce the number of non-trivial domtree queries by about 1% when
compiling sqlite3, by only doing dom queries after the cheap check
rather than interleaved with it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149836 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-05 15:50:43 +00:00
Stepan Dyatkovskiy
24473120a2 SwitchInst refactoring.
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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149481 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-01 07:49:51 +00:00
Bill Wendling
b319f12727 Increase the initial vector size to be equivalent to the size of the Deps
vector. This potentially saves a resizing.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149369 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-31 07:04:52 +00:00
Bill Wendling
5d8ab0f02b Cache the size of the vector instead of calling .size() all over the place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149368 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-31 06:57:53 +00:00
Chad Rosier
0cf6b99b96 Typo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149289 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-30 22:44:13 +00:00
Chad Rosier
431985a421 Typo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149275 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-30 21:13:22 +00:00
Chad Rosier
618c1dbd29 Propagate TargetLibraryInfo throughout ConstantFolding.cpp and
InstructionSimplify.cpp.  Other fixups as needed.
Part of rdar://10500969

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145559 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-01 03:08:23 +00:00
Duncan Sands
1673b15da2 Don't replace all dominated uses if there is only one use, since that
use can't be dominated, saving one domtree lookup.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142066 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-15 11:13:42 +00:00
Eli Friedman
b414142036 Enhance the memdep interface so that users can tell the difference between a dependency which cannot be calculated and a path reaching the entry point of the function. This patch introduces isNonFuncLocal, which replaces isUnknown in some cases.
Patch by Xiaoyi Guo.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141896 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-13 22:14:57 +00:00
Duncan Sands
3f329cb781 Teach GVN to also propagate switch cases. For example, in this code
switch (n) {
    case 27:
      do_something(x);
    ...
  }
the call do_something(x) will be replaced with do_something(27).  In
gcc-as-one-big-file this results in the removal of about 500 lines of
bitcode (about 0.02%), so has about 1/10 of the effect of propagating
branch conditions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141360 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-07 08:29:06 +00:00
Duncan Sands
02b5e72ac6 GVN does simple propagation of conditions: when it sees a conditional
branch "br i1 %x, label %if_true, label %if_false" then it replaces
"%x" with "true" in places only reachable via the %if_true arm, and
with "false" in places only reachable via the %if_false arm.  Except
that actually it doesn't: if value numbering shows that %y is equal
to %x then, yes, %y will be turned into true/false in this way, but
any occurrences of %x itself are not transformed.  Fix this.  What's
more, it's often the case that %x is an equality comparison such as
"%x = icmp eq %A, 0", in which case every occurrence of %A that is
only reachable via the %if_true arm can be replaced with 0.  Implement
this and a few other variations on this theme.  This reduces the number
of lines of LLVM IR in "GCC as one big file" by 0.2%.  It has a bigger
impact on Ada code, typically reducing the number of lines of bitcode
by around 0.4% by removing repeated compiler generated checks.  Passes
the LLVM nightly testsuite and the Ada ACATS testsuite.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141177 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 14:28:49 +00:00
Duncan Sands
452c58f4c4 Generalize GVN's conditional propagation logic slightly:
it's OK for the false/true destination to have multiple
predecessors as long as the extra ones are dominated by
the branch destination.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141176 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 14:17:01 +00:00
Benjamin Kramer
a9390a4d5f Stop emitting instructions with the name "tmp" they eat up memory and have to be uniqued, without any benefit.
If someone prefers %tmp42 to %42, run instnamer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140634 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-27 20:39:19 +00:00
Jakub Staszak
8cec759339 Compare type size instead of type _store_ size to make sure that BitCastInst
will be valid. This fixes PR10820.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139005 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-02 14:57:37 +00:00
Eli Friedman
56efe24431 Atomic load/store handling for the passes using memdep (GVN, DSE, memcpyopt).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137888 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-17 22:22:24 +00:00
Bill Wendling
795cf5efba Disable PRE for landing pads.
PRE needs the landing pads to have their critical edges split. Doing this for a
landing pad is non-trivial. Abandon the attempt to perform PRE when we come
across a landing pad. (Reviewed by Owen!)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137876 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-17 21:32:02 +00:00
Jay Foad
dab3d29605 Convert ConstantExpr::getGetElementPtr and
ConstantExpr::getInBoundsGetElementPtr to use ArrayRef.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135673 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-21 14:31:17 +00:00
Chris Lattner
db125cfaf5 land David Blaikie's patch to de-constify Type, with a few tweaks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135375 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-18 04:54:35 +00:00
Lang Hames
bd1828c6ed Added recognition for signed add/sub/mul with overflow intrinsics to GVN as per Chris and Frits suggestion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134777 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-09 00:25:11 +00:00
Lang Hames
1fb0955cab Make GVN look through extractvalues for recognised intrinsics. GVN can then CSE ops that match values produced by the intrinsics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134677 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-08 01:50:54 +00:00
Jay Foad
c137120bb0 Make better use of the PHINode API.
Change various bits of code to make better use of the existing PHINode
API, to insulate them from forthcoming changes in how PHINodes store
their operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133434 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-20 14:18:48 +00:00
Eli Friedman
a990e071f2 Add "unknown" results for memdep, which mean "I don't know whether a dependence for the given instruction exists in the given block". This cleans up all the existing hacks in memdep which represent this concept by returning clobber with various unrelated instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133031 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-15 00:47:34 +00:00
Chris Lattner
9e7bc05ad7 fix PR9841 by having GVN not process dead loads. This was
causing it to get into infinite loops when it would widen a 
load (which can necessarily leave around dead loads).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131847 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-22 07:03:34 +00:00
Devang Patel
de98568bf8 Preserve line number information.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131482 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-17 20:00:02 +00:00
Devang Patel
d9b4996637 Set debug loc for new load instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131481 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-17 19:43:38 +00:00
Devang Patel
0f18d97fd1 Set debug loc for new instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130895 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-04 23:58:50 +00:00
Chris Lattner
1e4f44bb8a improve comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130426 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-28 20:02:57 +00:00
Chris Lattner
0a9e3d613b final step needed to resolve PR6627, which allows us to flatten the code down to
a nice and tidy:
  %x1 = load i32* %0, align 4
  %1 = icmp eq i32 %x1, 1179403647
  br i1 %1, label %if.then, label %if.end

instead of doing lots of loads and branches.  May the FreeBSD bootloader
long fit in its allocated space.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130416 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-28 18:15:47 +00:00
Chris Lattner
ad3ba6a7de code cleanups only.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130414 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-28 18:08:21 +00:00
Chris Lattner
4756ecb375 centralize "marking for deletion" into a helper function. Pass GVN around to
static functions instead of passing around tons of random ivars.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130403 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-28 16:36:48 +00:00
Chris Lattner
f07054d98a Promote toErase to be an ivar of the GVN class.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130401 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-28 16:18:52 +00:00
Chris Lattner
4034e14985 teach GVN to widen integer loads when they are overaligned, when doing an
wider load would allow elimination of subsequent loads, and when the wider
load is still a native integer type.  This eliminates a ton of loads on 
various benchmarks involving struct fields, though it is somewhat hobbled
by clang not being very aggressive about field alignment.

This is yet another step along the way towards resolving PR6627.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130390 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-28 07:29:08 +00:00
Chris Lattner
9750acc079 Improve the bail-out predicate to really only kick in when phi
translation fails.  We were bailing out in some cases that would
cause us to miss GVN'ing some non-local cases away.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130206 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-26 17:41:02 +00:00