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llvm-project/llvm/test/Transforms/IndVarSimplify
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Chen Li 5cde8389cf [IndVarSimplify] Rewrite loop exit values with their initial values from loop preheader 
Summary:
This is a revised version of D13974, and the following quoted summary are from D13974

"This patch adds support to check if a loop has loop invariant conditions which lead to loop exits. If so, we know that if the exit path is taken, it is at the first loop iteration. If there is an induction variable used in that exit path whose value has not been updated, it will keep its initial value passing from loop preheader. We can therefore rewrite the exit value with
its initial value. This will help remove phis created by LCSSA and enable other optimizations like loop unswitch."

D13974 was committed but failed one lnt test. The bug was that we only checked the condition from loop exit's incoming block was a loop invariant. But there could be another condition from loop header to that incoming block not being a loop invariant. This would produce miscompiled code.

This patch fixes the issue by checking if the incoming block is loop header, and if not, don't perform the rewrite. The could be further improved by recursively checking all conditions leading to loop exit block, but I'd like to check in this simple version first and improve it with future patches.     

Reviewers: sanjoy

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D16570

llvm-svn: 258912
 		2016-01-27 07:40:41 +00:00
..
NVPTX [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
2002-09-09-PointerIndVar.ll
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2003-04-16-ExprAnalysis.ll
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2003-09-23-NotAtTop.ll
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2003-12-10-RemoveInstrCrash.ll
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2003-12-15-Crash.ll
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2004-03-10-PHIInsertionBug.ll
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2004-04-05-InvokeCastCrash.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
2004-04-07-ScalarEvolutionCrash.ll
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2005-02-11-InvokeCrash.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
2005-02-17-TruncateExprCrash.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
2005-02-26-ExitValueCompute.ll
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2005-06-15-InstMoveCrash.ll
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2005-11-18-Crash.ll [opaque pointer type] Add textual IR support for explicit type parameter to gep operator 2015-03-13 18:20:45 +00:00
2006-03-31-NegativeStride.ll
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2006-06-16-Indvar-LCSSA-Crash.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2006-09-20-LFTR-Crash.ll
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2006-12-10-BitCast.ll
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2007-01-06-TripCount.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2007-06-06-DeleteDanglesPtr.ll
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2007-11-23-BitcastCrash.ll
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2008-06-15-SCEVExpanderBug.ll
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2008-09-02-IVType.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
2008-10-03-CouldNotCompute.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2008-11-25-APFloatAssert.ll
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2009-04-14-shorten_iv_vars.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2009-04-15-shorten-iv-vars-2.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-IndvarCrash.ll
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2009-04-27-Floating.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
2009-05-24-useafterfree.ll
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2011-09-10-widen-nsw.ll This patch teaches IndVarSimplify to add nuw and nsw to certain kinds 2015-01-06 19:02:56 +00:00
2011-09-19-vectoriv.ll
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2011-09-27-hoistsext.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2011-10-27-lftrnull.ll [opaque pointer type] Add textual IR support for explicit type parameter to gep operator 2015-03-13 18:20:45 +00:00
2011-11-01-lftrptr.ll Verifier: Call verifyModule() from llc and opt 2015-03-27 22:04:28 +00:00
2011-11-15-multiexit.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2011-11-17-selfphi.ll
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2012-07-17-lftr-undef.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
2012-10-19-congruent-constant.ll
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2014-06-21-congruent-constant.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
ada-loops.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
ashr-tripcount.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
avoid-i0.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
backedge-on-min-max.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
bec-cmp.ll Make ScalarEvolution::isKnownPredicate a little smarter 2015-08-19 01:51:51 +00:00
casted-argument.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
const_phi.ll Fix PR25372 - teach replaceCongruentPHIs to handle cases where SE evaluates a PHI to a SCEVConstant 2015-11-03 16:27:04 +00:00
crash.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
dangling-use.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
divide-pointer.ll
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dont-recompute.ll
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elim-extend.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
eliminate-comparison.ll Re-apply r251050 with a for PR25421 2015-11-05 23:45:38 +00:00
eliminate-max.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
eliminate-rem.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
exit_value_test2.ll Enable exitValue rewrite only when the cost of expansion is low. 2015-05-28 21:49:07 +00:00
exit_value_test3.ll Enable exitValue rewrite only when the cost of expansion is low. 2015-05-28 21:49:07 +00:00
exit_value_tests.ll
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floating-point-iv.ll
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indirectbr.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
interesting-invoke-use.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
iterationCount_zext_or_trunc.ll
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iv-fold.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
iv-sext.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
iv-widen.ll [IndVars] Have `cloneArithmeticIVUser` guess better 2015-10-16 01:00:47 +00:00
iv-zext.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
lcssa-preservation.ll Enable exitValue rewrite only when the cost of expansion is low. 2015-05-28 21:49:07 +00:00
lftr-address-space-pointers.ll Revert some changes that were made to fix PR20680. 2015-03-02 21:41:07 +00:00
lftr-extend-const.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
lftr-other-uses.ll
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lftr-promote.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
lftr-reuse.ll Revert some changes that were made to fix PR20680. 2015-03-02 21:41:07 +00:00
lftr-udiv-tripcount.ll [SCEV] Strengthen SCEVExpander::isHighCostExpansion. 2015-04-14 03:20:32 +00:00
lftr-zext.ll [opaque pointer type] Add textual IR support for explicit type parameter to gep operator 2015-03-13 18:20:45 +00:00
lftr_simple.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
loop-invariant-conditions.ll [IndVars] Make loop varying predicates loop invariant. 2015-07-27 21:42:49 +00:00
loop_evaluate7.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
loop_evaluate8.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
loop_evaluate9.ll [opaque pointer type] Add textual IR support for explicit type parameter to gep operator 2015-03-13 18:20:45 +00:00
loop_evaluate10.ll
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loop_evaluate11.ll
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loop_evaluate_1.ll
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loop_evaluate_2.ll
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loop_evaluate_3.ll
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loop_evaluate_4.ll
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loop_evaluate_5.ll
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loop_evaluate_6.ll
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lrev-existing-umin.ll [IndVars] Try to use existing values in RewriteLoopExitValues. 2015-07-09 18:46:12 +00:00
masked-iv.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
no-iv-rewrite.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
overflowcheck.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
phi-uses-value-multiple-times.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
polynomial-expand.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
pr18223.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
pr20680.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
pr22222.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
pr24356.ll [IndVars] Fix PR24356. 2015-08-06 20:43:41 +00:00
pr24783.ll [IndVars] Fix PR24783. 2015-09-15 23:45:39 +00:00
pr24804.ll [SCEVExpander] Have hoistIVInc preserve LCSSA 2015-12-08 00:13:17 +00:00
pr24952.ll [SCEV] identical instructions don't compute equal values 2015-09-27 21:09:48 +00:00
pr24956.ll [SCEV] Don't crash on pointer comparisons 2015-09-28 21:14:32 +00:00
pr25047.ll [IndVars] Preserve LCSSA in `eliminateIdentitySCEV` 2015-10-07 17:38:31 +00:00
pr25051.ll [IndVars] Don't break dominance in `eliminateIdentitySCEV` 2015-10-06 21:44:49 +00:00
pr25060.ll [SCEV] Pick backedge values for phi nodes correctly 2015-10-08 18:28:36 +00:00
pr25360.ll [SCEV] Don't create SCEV expressions that break LCSSA 2015-10-31 23:21:40 +00:00
pr25421.ll Re-apply r251050 with a for PR25421 2015-11-05 23:45:38 +00:00
pr25576.ll [IndVars] Fix PR25576 2016-01-17 18:12:52 +00:00
pr25578.ll [IndVars] Have getInsertPointForUses preserve LCSSA 2015-12-08 00:13:21 +00:00
pr26207.ll [SCEV] Fix PR26207 2016-01-19 20:53:51 +00:00
preserve-signed-wrap.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
promote-iv-to-eliminate-casts.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
rewrite-loop-exit-value.ll [IndVarSimplify] Rewrite loop exit values with their initial values from loop preheader 2016-01-27 07:40:41 +00:00
sharpen-range.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
shrunk-constant.ll
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signed-trip-count.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
single-element-range.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
sink-alloca.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
sink-trapping.ll
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strengthen-overflow.ll Fix PR22222 2015-01-15 01:46:09 +00:00
tripcount_compute.ll
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tripcount_infinite.ll FileCheck'ify some wc/grep based tests; NFCI. 2015-07-28 03:50:09 +00:00
udiv-invariant-but-traps.ll
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udiv.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
uglygep.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
ult-sub-to-eq.ll Make DataLayout Non-Optional in the Module 2015-03-04 18:43:29 +00:00
use-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
variable-stride-ivs-0.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
variable-stride-ivs-1.ll
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verify-scev.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
widen-loop-comp.ll [IndVars] Fix a bug in r248045. 2015-09-20 01:52:18 +00:00
widen-nsw.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
zext-nuw.ll ScalarEvolution: do not set nuw when creating exprs of form <expr> + <all-ones>. 2015-11-20 01:26:13 +00:00