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llvm-project/llvm/test/Analysis/ScalarEvolution
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Oleg Ranevskyy eb4eccae5c [SCEV] No-wrap flags are not propagated when folding "{S,+,X}+T ==> {S+T,+,X}" 
Summary:
**Description**

This makes `WidenIV::widenIVUse` (IndVarSimplify.cpp) fail to widen narrow IV uses in some cases. The latter affects IndVarSimplify which may not eliminate narrow IV's when there actually exists such a possibility, thereby producing ineffective code.

When `WidenIV::widenIVUse` gets a NarrowUse such as `{(-2 + %inc.lcssa),+,1}<nsw><%for.body3>`, it first tries to get a wide recurrence for it via the `getWideRecurrence` call.
`getWideRecurrence` returns recurrence like this: `{(sext i32 (-2 + %inc.lcssa) to i64),+,1}<nsw><%for.body3>`.

Then a wide use operation is generated by `cloneIVUser`. The generated wide use is evaluated to `{(-2 + (sext i32 %inc.lcssa to i64))<nsw>,+,1}<nsw><%for.body3>`, which is different from the `getWideRecurrence` result. `cloneIVUser` sees the difference and returns nullptr.

This patch also fixes the broken LLVM tests by adding missing <nsw> entries introduced by the correction.

**Minimal reproducer:**
```
int foo(int a, int b, int c);
int baz();

void bar()
{
   int arr[20];
   int i = 0;

   for (i = 0; i < 4; ++i)
     arr[i] = baz();

   for (; i < 20; ++i)
     arr[i] = foo(arr[i - 4], arr[i - 3], arr[i - 2]);
}
```

**Clang command line:**
```
clang++ -mllvm -debug -S -emit-llvm -O3 --target=aarch64-linux-elf test.cpp -o test.ir
```

**Expected result:**
The ` -mllvm -debug` log shows that all the IV's for the second `for` loop have been eliminated.

Reviewers: sanjoy

Subscribers: atrick, asl, aemerson, mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D20058

llvm-svn: 270695
 		2016-05-25 13:01:33 +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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expander-replace-congruent-ivs.ll [SCEVExpander] Fix a failed cast<> assertion 2016-05-11 17:41:41 +00:00
ext-antecedent.ll [SCEV] Revert bailout added in r75511. 2015-03-26 17:28:26 +00:00
flags-from-poison.ll [SCEV] No-wrap flags are not propagated when folding "{S,+,X}+T ==> {S+T,+,X}" 2016-05-25 13:01:33 +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
guards.ll [SCEV] Use guards to prove predicates 2016-05-10 00:31:49 +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
increasing-or-decreasing-iv.ll Remove trailing newline from test case; NFC 2016-03-09 01:51:44 +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
no-wrap-unknown-becount.ll [SCEV] Be more aggressive in proving NUW 2016-05-17 17:51:14 +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 [SCEV] No-wrap flags are not propagated when folding "{S,+,X}+T ==> {S+T,+,X}" 2016-05-25 13:01:33 +00:00
nsw-offset.ll [SCEV] No-wrap flags are not propagated when folding "{S,+,X}+T ==> {S+T,+,X}" 2016-05-25 13:01:33 +00:00
nsw.ll [SCEV] No-wrap flags are not propagated when folding "{S,+,X}+T ==> {S+T,+,X}" 2016-05-25 13:01:33 +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
predicated-trip-count.ll Re-commit [SCEV] Introduce a guarded backedge taken count and use it in LAA and LV 2016-04-08 14:29:09 +00:00
range-signedness.ll [SCEV] Unify getUnsignedRange and getSignedRange 2015-03-09 21:43:43 +00:00
scev-aa.ll [PM/AA] Wire up SCEVAA to the new pass manager's registry and test it. 2016-02-20 04:01:45 +00:00
scev-canonical-mode.ll This patch is to fix PR26529 caused by r259736. 2016-02-09 00:07:08 +00:00
scev-dispositions.ll [SCEV] Tweak the output format and content of -analyze 2016-05-03 17:49:57 +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
sext-to-zext.ll [SCEV] Be less eager about demoting zexts to sexts 2016-03-03 18:31:23 +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