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path: root/lib/Analysis/InstructionSimplify.cpp
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2010-11-29Add some dead stores to pacify my least favorite GCC warning: may beChandler Carruth
uninitialized. The warning is terrible, has incorrect source locations, and has a huge false positive rate such as *all* of these. If anyone has a better solution, please let me know. Alternatively, I'll happily add -Wno-uninitialized to the -Werror build mode. Maybe I can even do it *only* when building with GCC instead of Clang. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120281 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-23Expand a little on the description of what InstructionSimplify does.Duncan Sands
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120016 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-22If a GEP index simply advances by multiples of a type of zero size,Duncan Sands
then replace the index with zero. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119974 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-22Move the "gep undef" -> "undef" transform from instcombine toDuncan Sands
InstructionSimplify. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119970 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-21Add a rather pointless InstructionSimplify transform, inspired by recent ↵Duncan Sands
constant folding improvements: if P points to a type of size zero, turn "gep P, N" into "P". More generally, if a gep index type has size zero, instcombine could replace the index with zero, but that is not done here. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119942 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-19Remove threading of Xor over selects and phis, with an explanationDuncan Sands
of why such threading is pointless. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119798 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17Move some those Xor simplifications which don't require creating newDuncan Sands
instructions out of InstCombine and into InstructionSimplify. While there, introduce an m_AllOnes pattern to simplify matching with integers and vectors with all bits equal to one. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119536 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17Previously SimplifyInstruction could report that an instructionDuncan Sands
simplified to itself (this can only happen in unreachable blocks). Change it to return null instead. Hopefully this will fix some buildbot failures. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119490 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17Fix a layering violation: hasConstantValue, which is part of the PHINodeDuncan Sands
class, uses DominatorTree which is an analysis. This change moves all of the tricky hasConstantValue logic to SimplifyInstruction, and replaces it with a very simple literal implementation. I already taught users of hasConstantValue that need tricky stuff to use SimplifyInstruction instead. I didn't update InlineFunction because the IR looks like it might be in a funky state at the point it calls hasConstantValue, which makes calling SimplifyInstruction dangerous since it can in theory do a lot of tricky reasoning. This may be a pessimization, for example in the case where all phi node operands are either undef or a fixed constant. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119459 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-16In which I discover the existence of loops. Threading an operationDuncan Sands
over a phi node by applying it to each operand may be wrong if the operation and the phi node are mutually interdependent (the testcase has a simple example of this). So only do this transform if it would be correct to perform the operation in each predecessor of the block containing the phi, i.e. if the other operands all dominate the phi. This should fix the FFMPEG snow.c regression reported by İsmail Dönmez. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119347 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-15Teach InstructionSimplify the trick of skipping incoming phiDuncan Sands
values that are equal to the phi itself. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119161 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-14If dom tree information is available, make it possible to passDuncan Sands
it to get better phi node simplification. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119055 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-14Teach InstructionSimplify about phi nodes. I chose to have it simplyDuncan Sands
offload the work to hasConstantValue rather than do something more complicated (such handling mutually recursive phis) because (1) it is not clear it is worth it; and (2) if it is worth it, maybe such logic would be better placed in hasConstantValue. Adjust some GVN tests which are now cleaned up much further (eg: all phi nodes are removed). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119043 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-14Strip trailing whitespace.Duncan Sands
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119038 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10Reduce the maximum recursion depth, 5 seems pointlessly too much.Duncan Sands
Probably it should just be 1, but compromise with 3. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118718 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10Teach InstructionSimplify how to look through PHI nodes. Since PHIDuncan Sands
nodes can be used in loops, this could result in infinite looping if there is no recursion limit, so add such a limit. It is also used for the SelectInst case because in theory there could be an infinite loop there too if the basic block is unreachable. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118694 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10Simplify binary operations where one operand is a select instruction.Duncan Sands
The simplifications performed here never create new instructions, they only return existing instructions (or a constant), and so are always a win. In theory they should transform (for example) %z = and i32 %x, %y %s = select i1 %cond, i32 %y, i32 %z %r = and i32 %x, %s into %r = and i32 %x, y but in practice they get into a fight with instcombine, and lose. Unfortunately instcombine does a poor job in this case. Nonetheless I'm committing this transform to make it easier to discuss what to do to make peace with instcombine. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118679 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-09Factorize code, no functionality change.Duncan Sands
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118516 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-07Add simplification of floating point comparisons with the resultDuncan Sands
of a select instruction, the same as already exists for integer comparisons. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118379 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-07Fix a README item: when doing a comparison with the resultDuncan Sands
of a select instruction, see if doing the compare with the true and false values of the select gives the same result. If so, that can be used as the value of the comparison. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118378 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-16Revert r114097, adding back in the assertion against replacing an ↵Owen Anderson
Instruction by itself. Now that CorrelatedValuePropagation is more careful not to call SimplifyInstructionsInBlock() on an unreachable block, the issue has been fixed at a higher level. Add a big warning to SimplifyInstructionsInBlock() to hopefully prevent this in the future. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114117 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-16Fix PR8161, in which an unreachable loop causes recursive instruction ↵Owen Anderson
simplification to try to replace an instruction with itself. Add a predicate to the simplifier to prevent this case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114097 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-10Teach InstructionSimplify to fold (A & B) & A -> A & B and (A | B) | A -> A | B.Benjamin Kramer
Reassociate does this but it doesn't catch all cases (e.g. if the operands are i1). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113651 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-15Fix PR7647, handling the case when 'To' ends up being Chris Lattner
mutated by recursive simplification. This also enhances ReplaceAndSimplifyAllUses to actually do a real RAUW at the end of it, which updates any value handles pointing to "From" to start pointing to "To". This seems useful for debug info and random other VH users. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108415 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-15Revert r108401; it breaks bootstrap :(Eli Friedman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108407 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-15Add AssertingVH which makes PR7647 break consistently.Eli Friedman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108401 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-20move some select simplifications out out instcombine intoChris Lattner
inst simplify. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101873 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03fix incorrect folding of icmp with undef, PR6481.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97659 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-22Constant-fold certain comparisons with infinity and negative infinity.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96777 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-27factor some logic out of instcombine into a new SimplifyAddInst method.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90011 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-27factor some instcombine simplifications for getelementptr out to a new Chris Lattner
SimplifyGEPInst method in InstructionSimplify.h. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89980 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10move some generally useful functions out of jump threadingChris Lattner
into libanalysis and transformutils. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86735 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10I misread the parens, not so redundant after all.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86648 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10remove some redundant parens.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86645 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10add a new SimplifyInstruction API, which is like ConstantFoldInstruction, Chris Lattner
except that the result may not be a constant. Switch jump threading to use it so that it gets things like (X & 0) -> 0, which occur when phi preds are deleted and the remaining phi pred was a zero. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86637 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10factor simplification logic for AND and OR out to InstSimplify from instcombine.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86635 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-09pull a bunch of logic out of instcombine into instsimplify for compare Chris Lattner
simplification, this handles the foldable fcmp x,x cases among many others. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86627 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-09rename SimplifyCompare -> SimplifyCmpInst and split it into Chris Lattner
Simplify[IF]Cmp pieces. Add some predicates to CmpInst to determine whether a predicate is fp or int. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86624 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-09fix ConstantFoldCompareInstOperands to take the LHS/RHS asChris Lattner
individual operands instead of taking a temporary array git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86619 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-09stub out a new libanalysis "instruction simplify" interface thatChris Lattner
takes decimated instructions and applies identities to them. This is pretty minimal at this point, but I plan to pull some instcombine logic out into these and similar routines. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86613 91177308-0d34-0410-b5e6-96231b3b80d8
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