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llvm-project/llvm/test/Analysis/ScalarEvolution
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Wei Mi a49559befb [SCEV] Try to reuse existing value during SCEV expansion 
Current SCEV expansion will expand SCEV as a sequence of operations
and doesn't utilize the value already existed. This will introduce
redundent computation which may not be cleaned up throughly by
following optimizations.

This patch introduces an ExprValueMap which is a map from SCEV to the
set of equal values with the same SCEV. When a SCEV is expanded, the
set of values is checked and reused whenever possible before generating
a sequence of operations.

The original commit triggered regressions in Polly tests. The regressions
exposed two problems which have been fixed in current version.

1. Polly will generate a new function based on the old one. To generate an
instruction for the new function, it builds SCEV for the old instruction,
applies some tranformation on the SCEV generated, then expands the transformed
SCEV and insert the expanded value into new function. Because SCEV expansion
may reuse value cached in ExprValueMap, the value in old function may be
inserted into new function, which is wrong.
   In SCEVExpander::expand, there is a logic to check the cached value to
be used should dominate the insertion point. However, for the above
case, the check always passes. That is because the insertion point is
in a new function, which is unreachable from the old function. However
for unreachable node, DominatorTreeBase::dominates thinks it will be
dominated by any other node.
   The fix is to simply add a check that the cached value to be used in
expansion should be in the same function as the insertion point instruction.

2. When the SCEV is of scConstant type, expanding it directly is cheaper than
reusing a normal value cached. Although in the cached value set in ExprValueMap,
there is a Constant type value, but it is not easy to find it out -- the cached
Value set is not sorted according to the potential cost. Existing reuse logic
in SCEVExpander::expand simply chooses the first legal element from the cached
value set.
   The fix is that when the SCEV is of scConstant type, don't try the reuse
logic. simply expand it.

Differential Revision: http://reviews.llvm.org/D12090

llvm-svn: 259736
 		2016-02-04 01:27:38 +00:00
..
2007-07-15-NegativeStride.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
2007-08-06-MisinterpretBranch.ll
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2007-08-06-Unsigned.ll
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2007-09-27-LargeStepping.ll
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2007-11-14-SignedAddRec.ll
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2007-11-18-OrInstruction.ll
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2008-02-11-ReversedCondition.ll
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2008-02-12-SMAXTripCount.ll
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2008-02-15-UMax.ll
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2008-05-25-NegativeStepToZero.ll
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2008-06-12-BinomialInt64.ll
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2008-07-12-UnneededSelect1.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2008-07-12-UnneededSelect2.ll
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2008-07-19-InfiniteLoop.ll
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2008-07-19-WrappingIV.ll
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2008-07-29-SGTTripCount.ll
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2008-07-29-SMinExpr.ll
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2008-08-04-IVOverflow.ll
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2008-08-04-LongAddRec.ll
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2008-11-02-QuadraticCrash.ll
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2008-11-15-CubicOOM.ll
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2008-11-18-LessThanOrEqual.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
2008-11-18-Stride1.ll
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2008-11-18-Stride2.ll
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2008-12-08-FiniteSGE.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2008-12-11-SMaxOverflow.ll
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2008-12-14-StrideAndSigned.ll
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2008-12-15-DontUseSDiv.ll
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2009-01-02-SignedNegativeStride.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2009-04-22-TruncCast.ll
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2009-05-09-PointerEdgeCount.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
2009-07-04-GroupConstantsWidthMismatch.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2010-09-03-RequiredTransitive.ll
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2011-03-09-ExactNoMaxBECount.ll
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2011-04-26-FoldAddRec.ll
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2011-10-04-ConstEvolve.ll
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2012-03-26-LoadConstant.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
2012-05-18-LoopPredRecurse.ll
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2012-05-29-MulAddRec.ll
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SolveQuadraticEquation.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
and-xor.ll
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avoid-assume-hang.ll ScalarEvolution assume hanging bugfix 2015-09-09 20:47:30 +00:00
avoid-infinite-recursion-0.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
avoid-infinite-recursion-1.ll
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avoid-smax-0.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
avoid-smax-1.ll Revert "Change memcpy/memset/memmove to have dest and source alignments." 2015-11-19 05:56:52 +00:00
constant_condition.ll Revert "Revert "This patch builds on top of D13378 to handle constant condition."" 2015-10-07 18:14:25 +00:00
div-overflow.ll
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do-loop.ll
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ext-antecedent.ll [SCEV] Revert bailout added in r75511. 2015-03-26 17:28:26 +00:00
flags-from-poison.ll [SCEV] Apply NSW and NUW flags via poison value analysis for sub, mul and shl 2015-08-14 22:45:26 +00:00
fold.ll When simplifying a SCEV truncate by distributing, consider it a simplification to replace a cast, even if we end up with a trunc around the term. Fixes PR22960! 2015-03-20 02:25:00 +00:00
how-far-to-zero.ll
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incorrect-nsw.ll Bugfix: SCEV incorrectly marks certain add recurrences as nsw 2015-02-09 18:34:55 +00:00
infer-prestart-no-wrap.ll [SCEV] Mark AddExprs as nsw or nuw if legal 2015-10-22 19:57:19 +00:00
infer-via-ranges.ll [SCEV] Make isImpliedCond smarter. 2015-03-18 00:41:29 +00:00
latch-dominating-conditions.ll [SCEV] Look at backedge dominating conditions (re-land r233447). 2015-04-01 18:24:06 +00:00
load-with-range-metadata.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
load.ll [SCEV] Add a `scalar-evolution-print-constant-ranges' option 2015-03-09 21:43:39 +00:00
max-trip-count-address-space.ll [SCEV] Add a `scalar-evolution-print-constant-ranges' option 2015-03-09 21:43:39 +00:00
max-trip-count.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
min-max-exprs.ll [SCEV] Mark AddExprs as nsw or nuw if legal 2015-10-22 19:57:19 +00:00
no-wrap-add-exprs.ll [SCEV] Commute zero extends through <nuw> additions 2015-10-22 19:57:38 +00:00
non-IV-phi.ll [SCEV] Generalize the SCEV algorithm for creating expressions for PHI nodes 2015-10-30 15:02:28 +00:00
nowrap-preinc-limits.ll [SCEV] make SCEV smarter about proving no-wrap. 2015-03-04 22:24:17 +00:00
nsw-offset-assume.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
nsw-offset.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
nsw.ll [SCEV] Add a `scalar-evolution-print-constant-ranges' option 2015-03-09 21:43:39 +00:00
nw-sub-is-not-nw-add.ll Make ScalarEvolution less aggressive with respect to no-wrap flags. 2015-01-22 00:48:47 +00:00
pointer-sign-bits.ll
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pr3909.ll
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pr22179.ll [opaque pointer type] Add textual IR support for explicit type parameter to gep operator 2015-03-13 18:20:45 +00:00
pr22641.ll Fix bug 22641 2015-02-24 01:02:42 +00:00
pr22674.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
pr22856.ll [SCEV] Fix PR22856. 2015-03-13 18:31:19 +00:00
pr24757.ll [ScalarEvolution] Fix PR24757. 2015-09-10 05:27:38 +00:00
pr25369.ll [SCEV] Fix PR25369 2015-11-02 02:06:01 +00:00
range-signedness.ll [SCEV] Unify getUnsignedRange and getSignedRange 2015-03-09 21:43:43 +00:00
scev-aa.ll [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
scev-expander-existing-value.ll [SCEV] Try to reuse existing value during SCEV expansion 2016-02-04 01:27:38 +00:00
scev-expander-incorrect-nowrap.ll Bugfix: SCEVExpander incorrectly marks increment operations as no-wrap 2015-02-25 20:02:59 +00:00
scev-invalid.ll
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scev-prestart-nowrap.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
sext-inreg.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
sext-iv-0.ll [SCEV] Add a `scalar-evolution-print-constant-ranges' option 2015-03-09 21:43:39 +00:00
sext-iv-1.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
sext-iv-2.ll [opaque pointer type] Add textual IR support for explicit type parameter to gep operator 2015-03-13 18:20:45 +00:00
shift-op.ll [SCEV] Compute max backedge count for loops with "shift ivs" 2015-10-28 21:27:14 +00:00
sle.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
smax-br-phi-idioms.ll [SCEV] Don't create SCEV expressions that break LCSSA 2015-10-31 23:21:40 +00:00
smax.ll
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trip-count-pow2.ll ScalarEvolution: HowFarToZero was wrongly using signed division 2014-11-16 07:30:35 +00:00
trip-count-switch.ll
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trip-count.ll Revert "Change memcpy/memset/memmove to have dest and source alignments." 2015-11-19 05:56:52 +00:00
trip-count2.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
trip-count3.ll Revert "Change memcpy/memset/memmove to have dest and source alignments." 2015-11-19 05:56:52 +00:00
trip-count4.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
trip-count5.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
trip-count6.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
trip-count7.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
trip-count8.ll
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trip-count9.ll
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trip-count10.ll
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trip-count11.ll [SCEV] Add a `scalar-evolution-print-constant-ranges' option 2015-03-09 21:43:39 +00:00
trip-count12.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
undefined.ll
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unreachable-code.ll
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unsimplified-loop.ll
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zext-signed-addrec.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
zext-wrap.ll [SCEV] Reapply 'Teach isLoopBackedgeGuardedByCond to exploit trip counts' 2015-09-25 23:53:50 +00:00