Sanjoy Das 9302e9a500 [DSE] Don't DSE stores that subsequent memmove calls read from ...

Summary:
We used to remove the first memmove in cases like this:

  memmove(p, p+2, 8);
  memmove(p, p+2, 8);

which is incorrect.  Fix this by changing isPossibleSelfRead to what was most
likely the intended behavior.

Historical note: the buggy code was added in https://reviews.llvm.org/rL120974
to address PR8728.

Reviewers: rsmith

Subscribers: mcrosier, llvm-commits, jlebar

Differential Revision: https://reviews.llvm.org/D43425

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325641 91177308-0d34-0410-b5e6-96231b3b80d8

2018-02-20 23:19:34 +00:00

..

2011-03-25-DSEMiscompile.ll

[opaque pointer type] Add textual IR support for explicit type parameter to load instruction

2015-02-27 21:17:42 +00:00

2011-09-06-EndOfFunction.ll

[opaque pointer type] Add textual IR support for explicit type parameter to load instruction

2015-02-27 21:17:42 +00:00

2011-09-06-MemCpy.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

2016-07-17-UseAfterFree.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

atomic.ll

MemoryDependenceAnalysis: Don't miscompile atomics

2015-03-21 06:19:17 +00:00

calloc-store.ll

[DeadStoreElimination] Remove dead zero store to calloc initialized memory

2015-09-23 11:38:44 +00:00

combined-partial-overwrites.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

const-pointers.ll

[opaque pointer type] Add textual IR support for explicit type parameter to load instruction

2015-02-27 21:17:42 +00:00

crash.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

cs-cs-aliasing.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

debuginfo.ll

[DeadStoreElimination] Salvage debug info from dead insts

2018-02-13 18:15:26 +00:00

dominate.ll

Add address space mangling to lifetime intrinsics

2017-04-10 20:18:21 +00:00

fence.ll

[DSE] Remove dead stores in end blocks containing fence

2016-07-07 20:51:42 +00:00

free.ll

[DSE] Don't remove stores made live by a call which unwinds.

2016-08-12 01:09:53 +00:00

inst-limits.ll

Remove the obsolete offset parameter from @llvm.dbg.value

2017-07-28 20:21:02 +00:00

int_sideeffect.ll

Add an @llvm.sideeffect intrinsic

2017-11-08 21:59:51 +00:00

invariant.start.ll

[AliasAnalysis] Treat invariant.start as read-memory

2016-08-09 17:18:05 +00:00

libcalls.ll

[opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction

2015-02-27 19:29:02 +00:00

lifetime.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

mda-with-dbg-values.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

memintrinsics.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

merge-stores-big-endian.ll

[DSE] Merge stores when the later store only writes to memory locations the early store also wrote to (2nd try)

2017-09-26 13:54:28 +00:00

merge-stores.ll

[DSE] make sure memory is not modified before partial store merging (PR36129)

2018-01-30 13:53:59 +00:00

no-targetdata.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

operand-bundles.ll

[DeadStoreElimination] Check function modref behavior before considering memory clobbered

2017-03-01 14:38:29 +00:00

OverwriteStoreBegin.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

OverwriteStoreEnd.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

PartialStore.ll

[DSE] Merge stores when the later store only writes to memory locations the early store also wrote to (2nd try)

2017-09-26 13:54:28 +00:00

pr11390.ll

Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)

2018-01-19 17:13:12 +00:00

simple.ll

[DSE] Don't DSE stores that subsequent memmove calls read from

2018-02-20 23:19:34 +00:00