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7774 Commits

Author SHA1 Message Date
Chih-Hung Hsieh
598a327133 [Analysis] Disable calls to *_finite and other glibc-only functions on Android.
Since r322087, glibc's finite lib calls are generated when possible.
However, they are not supported on Android. This change also
disables other functions not available on Android.

Differential Revision: http://reviews.llvm.org/D42668

llvm-svn: 323898
2018-01-31 19:12:50 +00:00
Daniel Neilson
dd97f56777 [Lint] Upgrade uses of MemoryIntrinic::getAlignment() to new API. (NFCI)
Summary:
  This change is part of step five in the series of changes to remove alignment argument from
memcpy/memmove/memset in favour of alignment attributes. In particular, this changes the Lint
analysis to cease using the old getAlignment() API of MemoryIntrinsic in favour of getting
source & dest specific alignments through the new API.

Steps:
Step 1) Remove alignment parameter and create alignment parameter attributes for
memcpy/memmove/memset. ( rL322965, rC322964, rL322963 )
Step 2) Expand the IRBuilder API to allow creation of memcpy/memmove with differing
source and dest alignments. ( rL323597 )
Step 3) Update Clang to use the new IRBuilder API. ( rC323617 )
Step 4) Update Polly to use the new IRBuilder API. ( rL323618 )
Step 5) Update LLVM passes that create memcpy/memmove calls to use the new IRBuilder API,
and those that use use MemIntrinsicInst::[get|set]Alignment() to use [get|set]DestAlignment()
and [get|set]SourceAlignment() instead.
Step 6) Remove the single-alignment IRBuilder API for memcpy/memmove, and the
MemIntrinsicInst::[get|set]Alignment() methods.

Reference
   http://lists.llvm.org/pipermail/llvm-dev/2015-August/089384.html
   http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html

llvm-svn: 323886
2018-01-31 16:42:15 +00:00
Zaara Syeda
e49dd688ba Re-commit : [PowerPC] Add handling for ColdCC calling convention and a pass to mark
candidates with coldcc attribute.

This recommits r322721 reverted due to sanitizer memory leak build bot failures.

Original commit message:
This patch adds support for the coldcc calling convention for Power.
This changes the set of non-volatile registers. It includes a pass to stress
test the implementation by marking all static directly called functions with
the coldcc attribute through the option -enable-coldcc-stress-test. It also
includes an option, -ppc-enable-coldcc, to add the coldcc attribute to
functions which are cold at all call sites based on BlockFrequencyInfo when
the containing function does not call any non cold functions.

Differential Revision: https://reviews.llvm.org/D38413

llvm-svn: 323778
2018-01-30 16:17:22 +00:00
Sanjay Patel
936f2110a3 [InstSimplify] (X * Y) / Y --> X for relaxed floating-point ops
This is the FP counterpart that was mentioned in PR35709:
https://bugs.llvm.org/show_bug.cgi?id=35709

Differential Revision: https://reviews.llvm.org/D42385

llvm-svn: 323716
2018-01-30 00:18:37 +00:00
Florian Hahn
b93b284e33 [InlineCost] Mark functions accessing varargs as not viable.
This prevents functions accessing varargs from being inlined if they
have the alwaysinline attribute.

Reviewers: efriedma, rnk, davide

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D42556

llvm-svn: 323619
2018-01-28 19:11:49 +00:00
Easwaran Raman
bd3a1aab59 [SyntheticCounts] Rewrite the code using only graph traits.
Summary:
The intent of this is to allow the code to be used with ThinLTO. In
Thinlink phase, a traditional Callgraph can not be computed even though
all the necessary information (nodes and edges of a call graph) is
available. This is due to the fact that CallGraph class is closely tied
to the IR. This patch first extends GraphTraits to add a CallGraphTraits
graph. This is then used to implement a version of counts propagation
on a generic callgraph.

Reviewers: davidxl

Subscribers: mehdi_amini, tejohnson, llvm-commits

Differential Revision: https://reviews.llvm.org/D42311

llvm-svn: 323475
2018-01-25 22:02:29 +00:00
Easwaran Raman
3831ff54c8 Re-land "[ThinLTO] Add call edges' relative block frequency to per-module summary."
It was reverted after buildbot regressions.

Original commit message:

This allows relative block frequency of call edges to be passed
to the thinlink stage where it will be used to compute synthetic
entry counts of functions.

llvm-svn: 323460
2018-01-25 19:27:17 +00:00
Easwaran Raman
144f3acb63 Revert "[ThinLTO] Add call edges' relative block frequency to per-module summary."
Causes buildbot regressions.

llvm-svn: 323358
2018-01-24 18:15:29 +00:00
Easwaran Raman
e7546e2838 [ThinLTO] Add call edges' relative block frequency to per-module summary.
Summary:
This allows relative block frequency of call edges to be passed to the
thinlink stage where it will be used to compute synthetic entry counts
of functions.

Reviewers: tejohnson, pcc

Subscribers: mehdi_amini, llvm-commits, inglorion

Differential Revision: https://reviews.llvm.org/D42212

llvm-svn: 323349
2018-01-24 17:51:23 +00:00
Zvi Rackover
2888e5cce2 InstSimplify: If divisor element is undef simplify to undef
Summary:
If any vector divisor element is undef, we can arbitrarily choose it be
zero which would make the div/rem an undef value by definition.

Reviewers: spatel, reames

Reviewed By: spatel

Subscribers: magabari, llvm-commits

Differential Revision: https://reviews.llvm.org/D42485

llvm-svn: 323343
2018-01-24 17:22:00 +00:00
Sanjay Patel
373af89ec1 [ValueTracking] add recursion depth param to matchSelectPattern
We're getting bug reports:
https://bugs.llvm.org/show_bug.cgi?id=35807
https://bugs.llvm.org/show_bug.cgi?id=35840
https://bugs.llvm.org/show_bug.cgi?id=36045
...where we blow up the stack in value tracking because other passes are sending 
in selects that have an operand that is itself the select.

We don't currently have a reliable way to avoid analyzing dead code that may take 
non-standard forms, so bail out when things go too far.

This mimics the recursion depth limitations in other parts of value tracking.

Unfortunately, this pushes the underlying problems for other passes (jump-threading,
simplifycfg, correlated-propagation) into hiding. If someone wants to uncover those
again, the first draft of this patch on Phab would do that (it would assert rather
than bail out).

Differential Revision: https://reviews.llvm.org/D42442

llvm-svn: 323331
2018-01-24 15:20:37 +00:00
Malcolm Parsons
12e0bc3d59 Fix typos of occurred and occurrence
llvm-svn: 323318
2018-01-24 10:33:39 +00:00
MinSeong Kim
789c857267 [Analysis] Disable exp/exp2/pow finite lib calls on Android with -ffast-math.
Summary:
Since r322087, glibc's finite lib calls are generated when possible.
However, glibc is not supported on Android. Therefore this change
enables llvm to finely distinguish between linux and Android for
unsupported library calls. The change also include some regression
tests.

Reviewers: srhines, pirama

Reviewed By: srhines

Subscribers: kongyi, chh, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D42288

llvm-svn: 323187
2018-01-23 11:11:36 +00:00
Anton Bikineev
00022a2f0a [InstSimplify] (X << Y) % X -> 0
llvm-svn: 323182
2018-01-23 09:27:47 +00:00
Eugene Leviant
828889d031 [ThinLTO] Re-commit of dot dumper after test fix
llvm-svn: 323116
2018-01-22 13:35:40 +00:00
Serguei Katkov
f696a727d6 Revert [SCEV] Fix isLoopEntryGuardedByCond usage
It causes buildbot failures. New added assert is fired.
It seems not all usages of isLoopEntryGuardedByCond are fixed.

llvm-svn: 323079
2018-01-22 07:47:02 +00:00
Serguei Katkov
1de2718db9 [SCEV] Fix isLoopEntryGuardedByCond usage
ScalarEvolution::isKnownPredicate invokes isLoopEntryGuardedByCond without check
that SCEV is available at entry point of the loop. It is incorrect and fixed by patch.

Reviewers: sanjoy, mkazantsev, anna, dorit
Reviewed By: mkazantsev
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D42165

llvm-svn: 323077
2018-01-22 07:31:41 +00:00
Eugene Leviant
de5a6e74a5 Temporarily revert r323062 to investigate buildbot failures
llvm-svn: 323065
2018-01-21 10:22:19 +00:00
Eugene Leviant
5a1f095ecc [ThinLTO] Implement summary visualizer
Differential revision: https://reviews.llvm.org/D41297

llvm-svn: 323062
2018-01-21 07:27:32 +00:00
Sanjay Patel
77ca2be326 [InstSimplify] use m_Specific and commutative matcher to reduce code; NFCI
llvm-svn: 322955
2018-01-19 16:12:55 +00:00
Alina Sbirlea
d3b0b1a228 [ModRefInfo] Return NoModRef for Must and NoModRef.
Summary:
In ModRefInfo "Must" was introduced to track presence of MustAlias, but we still want to return NoModRef when there is neither Mod or Ref, even when MustAlias is found. Patch has small fixes to ensure this happens.
Minor cleanup to remove nesting for 2 if statements when calling getModRefInfo for 2 ImmutableCallSites.

Reviewers: sanjoy

Subscribers: jlebar, llvm-commits

Differential Revision: https://reviews.llvm.org/D42209

llvm-svn: 322932
2018-01-19 10:26:40 +00:00
Easwaran Raman
a01ba52e92 Add a ProfileCount class to represent entry counts.
Summary:
The class wraps a uint64_t and an enum to represent the type of profile
count (real and synthetic) with some helper methods.

Reviewers: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41883

llvm-svn: 322771
2018-01-17 22:24:23 +00:00
Zaara Syeda
abe7cb3cc8 Revert [PowerPC] This reverts commit rL322721
Failing build bots. Revert the commit now.

llvm-svn: 322748
2018-01-17 20:00:15 +00:00
Philip Reames
d9e0521a88 [MDA] Use common code instead of reimplementing same. [NFC]
llvm-svn: 322747
2018-01-17 19:57:19 +00:00
Zaara Syeda
8aa2772618 [PowerPC] Add handling for ColdCC calling convention and a pass to mark
candidates with coldcc attribute.

This patch adds support for the coldcc calling convention for Power.
This changes the set of non-volatile registers. It includes a pass to stress
test the implementation by marking all static directly called functions with
the coldcc attribute through the option -enable-coldcc-stress-test. It also
includes an option, -ppc-enable-coldcc, to add the coldcc attribute to
functions which are cold at all call sites based on BlockFrequencyInfo when
the containing function does not call any non cold functions.

Differential Revision: https://reviews.llvm.org/D38413

llvm-svn: 322721
2018-01-17 18:22:55 +00:00
Hiroshi Inoue
4857d267aa [NFC] fix trivial typos in comments
"the the" -> "the"

llvm-svn: 322636
2018-01-17 12:29:38 +00:00
Mikael Holmen
455a18e971 [GlobalsAA] Don't let dbg intrinsics affect analysis result
Summary:
This fixes PR35899.

Debug info intrinsics shouldn't affect code generation so ignore them
in GlobalsAA.

Reviewers: hfinkel, aprantl

Reviewed By: aprantl

Subscribers: aprantl, llvm-commits

Differential Revision: https://reviews.llvm.org/D41984

llvm-svn: 322470
2018-01-15 07:05:51 +00:00
Davide Italiano
1e4933df39 [BasicAA] Stop crashing when dealing with pointers > 64 bits.
An alternative (and probably better) fix would be that of
making `Scale` an APInt, and there's a patch floating around
to do this. As we're still discussing it, at least stop crashing
in the meanwhile (added bonus, we now have a regression test for
this situation).

Fixes PR35843.

Thanks to Eli for suggesting the fix and Simon for reporting and
reducing the bug.

llvm-svn: 322467
2018-01-15 01:40:18 +00:00
Sanjay Patel
4430ada396 [InstSimplify] fix code comments; NFC
llvm-svn: 322456
2018-01-14 15:58:18 +00:00
Sanjay Patel
ae40514007 [InstSimplify] fold implied null ptr check (PR35790)
This extends rL322327 to handle the pointer cast and should solve:
https://bugs.llvm.org/show_bug.cgi?id=35790

Name: or_eq_zero
  %isnull = icmp eq i64* %p, null
  %x = ptrtoint i64* %p to i64
  %somebits = and i64 %x, %y
  %somebits_are_zero = icmp eq i64 %somebits, 0
  %or = or i1 %somebits_are_zero, %isnull
  =>
  %or = %somebits_are_zero

Name: and_ne_zero
  %isnotnull = icmp ne i64* %p, null
  %x = ptrtoint i64* %p to i64
  %somebits = and i64 %x, %y
  %somebits_are_not_zero = icmp ne i64 %somebits, 0
  %and = and i1 %somebits_are_not_zero, %isnotnull
  =>
  %and = %somebits_are_not_zero

https://rise4fun.com/Alive/CQ3

llvm-svn: 322439
2018-01-13 15:44:44 +00:00
Sanjay Patel
cbad481c69 [InstSimplify] fold implied cmp with zero (PR35790)
This doesn't handle the more complicated case in the bug report yet:
https://bugs.llvm.org/show_bug.cgi?id=35790

For that, we have to match / look through a cast.

llvm-svn: 322327
2018-01-11 23:27:37 +00:00
Sanjay Patel
384913118b [ValueTracking] recognize min/max-of-min/max with notted ops (PR35875)
This was originally planned as the fix for:
https://bugs.llvm.org/show_bug.cgi?id=35834
...but simpler transforms handled that case, so I implemented a 
lesser solution. It turns out we need to handle the case with 'not'
ops too because the real code example that we are trying to solve:
https://bugs.llvm.org/show_bug.cgi?id=35875
...has extra uses of the intermediate values, so we can't rely on 
smaller canonicalizations to get us to the goal.

As with rL321672, I've tried to show every possibility in the
codegen tests because that's the simplest way to prove we're doing
the right thing in the wide variety of permutations of this pattern.

We can also show an InstCombine win because we added a fold for
this case in:
rL321998 / D41603

An Alive proof for one variant of the pattern to show that the 
InstCombine and codegen results are correct:
https://rise4fun.com/Alive/vd1

Name: min3_nots
  %nx = xor i8 %x, -1
  %ny = xor i8 %y, -1
  %nz = xor i8 %z, -1
  %cmpxz = icmp slt i8 %nx, %nz
  %minxz = select i1 %cmpxz, i8 %nx, i8 %nz
  %cmpyz = icmp slt i8 %ny, %nz
  %minyz = select i1 %cmpyz, i8 %ny, i8 %nz
  %cmpyx = icmp slt i8 %y, %x
  %r = select i1 %cmpyx, i8 %minxz, i8 %minyz
=>
  %cmpxyz = icmp slt i8 %minxz, %ny
  %r = select i1 %cmpxyz, i8 %minxz, i8 %ny

Name: min3_nots_alt
  %nx = xor i8 %x, -1
  %ny = xor i8 %y, -1
  %nz = xor i8 %z, -1
  %cmpxz = icmp slt i8 %nx, %nz
  %minxz = select i1 %cmpxz, i8 %nx, i8 %nz
  %cmpyz = icmp slt i8 %ny, %nz
  %minyz = select i1 %cmpyz, i8 %ny, i8 %nz
  %cmpyx = icmp slt i8 %y, %x
  %r = select i1 %cmpyx, i8 %minxz, i8 %minyz
=>
  %xz = icmp sgt i8 %x, %z
  %maxxz = select i1 %xz, i8 %x, i8 %z
  %xyz = icmp sgt i8 %maxxz, %y
  %maxxyz = select i1 %xyz, i8 %maxxz, i8 %y
  %r = xor i8 %maxxyz, -1

llvm-svn: 322283
2018-01-11 15:13:47 +00:00
Bjorn Pettersson
7022e7d38f Avoid inlining if there is byval arguments with non-alloca address space
Summary:
After teaching InlineCost more about address spaces ()
another fault was detected in the inliner. If an argument has
the byval attribute the parameter might be copied to an alloca.
That part seems to work fine even if the argument has a different
address space than the alloca address space. However, if the
address spaces differ, then the inlined function still might
refer to the parameter using the original address space (the
inliner does not handle that situation very well).

This patch avoids the problem by simply disallowing inlining
when there are byval arguments with address space that differs
from the alloca address space.

I'm not really sure how to transform the code if we want to
get inlining for this situation. I assume that it never has
been working, and that the fixes in r321809 just exposed an
old problem.

Fault found by skatkov (Serguei Katkov). It is mentioned in
follow up comments to https://reviews.llvm.org/D40455.

Reviewers: skatkov

Reviewed By: skatkov

Subscribers: uabelho, eraman, llvm-commits, haicheng

Differential Revision: https://reviews.llvm.org/D41898

llvm-svn: 322181
2018-01-10 13:01:18 +00:00
Easwaran Raman
f04207e3b2 Add a pass to generate synthetic function entry counts.
Summary:
This pass synthesizes function entry counts by traversing the callgraph
and using the relative block frequencies of the callsites. The intended
use of these counts is in inlining to determine hot/cold callsites in
the absence of profile information.

The pass is split into two files with the code that propagates the
counts in a callgraph in a Utils file. I plan to add support for
propagation in the thinlto link phase and the propagation code will be
shared and hence this split. I did not add support to the old PM since
hot callsite determination in inlining is not possible in old PM
(although we could use hot callee heuristic with synthetic counts in the
old PM it is not worth the effort tuning it)

Reviewers: davidxl, silvas

Subscribers: mgorny, mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D41604

llvm-svn: 322110
2018-01-09 19:39:35 +00:00
Serguei Katkov
d58a989008 [SCEV] Do not cache S -> V if S is not equivalent of V
SCEV tracks the correspondence of created SCEV to original instruction.
However during creation of SCEV it is possible that nuw/nsw/exact flags are
lost.

As a result during expansion of the SCEV the instruction with nuw/nsw/exact
will be used where it was expected and we produce poison incorreclty.

Reviewers: sanjoy, mkazantsev, sebpop, jbhateja
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41578

llvm-svn: 322058
2018-01-09 06:47:14 +00:00
Sanjay Patel
60d5bad02a [ValueTracking] remove overzealous assert
The test is derived from a failing fuzz test:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5008

Credit to @rksimon for pointing out the problem.

llvm-svn: 322016
2018-01-08 18:31:13 +00:00
Sanjay Patel
a000fc9f42 [TargetLibraryInfo] fix finite mathlib function availability
This patch was part of:
https://reviews.llvm.org/D41338
...but we can expose the bug in IR via constant propagation
as shown in the test. Unless the triple includes 'linux', we
should not fold these because the functions don't exist on
other platforms (yet?).

llvm-svn: 322010
2018-01-08 17:38:09 +00:00
Florian Hahn
8724686a5d [InlineFunction] Inline vararg functions that do not access varargs.
If the varargs are not accessed by a function, we can inline the
function.

Reviewers: dblaikie, chandlerc, davide, efriedma, rnk, hfinkel

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D41335

llvm-svn: 321940
2018-01-06 19:45:40 +00:00
Davide Italiano
ed12e8725c [BasicAA] Fix linearization of shifts beyond the bitwidth.
Thanks to Simon Pilgrim for the reduced testcase.
Fixes PR35821.

llvm-svn: 321873
2018-01-05 16:18:47 +00:00
Bjorn Pettersson
793f08bf63 Teach InlineCost about address spaces
Summary:
I basically copied this patch from here:
  https://reviews.llvm.org/D1251
But I skipped some of the refactoring to make the patch more clean.

The new outer3/inner3 test case in ptr-diff.ll triggers the
following assert without this patch:
lib/IR/Constants.cpp:1834: static llvm::Constant *llvm::ConstantExpr::getCompare(unsigned short, llvm::Constant *, llvm::Constant *, bool): Assertion `C1->getType() == C2->getType() && "Op types should be identical!"' failed.

The other new test cases makes sure that there is code coverage
for all modifications in InlineCost.cpp (getting different values
due to not fetching sizes for address space zero). I only guarantee
code coverage for those tests. The tests are not written in a way
that they would break if not having the corrections in
InlineCost.cpp. I found it quite hard to fine tune the tests into
getting different results based on the pointer sizes (except for
the test case where we hit an assert if not teaching InlineCost
about address spaces).

Reviewers: chandlerc, arsenm, haicheng

Reviewed By: arsenm

Subscribers: wdng, eraman, llvm-commits, haicheng

Differential Revision: https://reviews.llvm.org/D40455

llvm-svn: 321809
2018-01-04 18:23:40 +00:00
Dmitry Venikov
5d983d0524 [InstSimplify] Missed optimization in math expression: squashing exp(log), log(exp)
Summary: This patch enables folding following expressions under -ffast-math flag: exp(log(x)) -> x, exp2(log2(x)) -> x, log(exp(x)) -> x, log2(exp2(x)) -> x

Reviewers: spatel, hfinkel, davide

Reviewed By: spatel, hfinkel, davide

Subscribers: scanon, llvm-commits

Differential Revision: https://reviews.llvm.org/D41381

llvm-svn: 321710
2018-01-03 14:37:42 +00:00
Sanjay Patel
e69e89e1b4 [ValueTracking] recognize min/max of min/max patterns
This is part of solving PR35717:
https://bugs.llvm.org/show_bug.cgi?id=35717

The larger IR optimization is proposed in D41603, but we can show 
the improvement in ValueTracking using codegen tests because 
SelectionDAG creates min/max nodes based on ValueTracking. 

Any target with min/max ops should show wins here. I chose AArch64
vector ops because they're clean and uniform.

Some Alive proofs for the tests (can't put more than 2 tests in 1 
page currently because the web app says it's too long):
https://rise4fun.com/Alive/WRN
https://rise4fun.com/Alive/iPm
https://rise4fun.com/Alive/HmY
https://rise4fun.com/Alive/CNm
https://rise4fun.com/Alive/LYf

llvm-svn: 321672
2018-01-02 20:56:45 +00:00
Dmitry Venikov
533cf488fd Test commit
Reviewers: Quolyk

Reviewed By: Quolyk

Differential Revision: https://reviews.llvm.org/D41561

llvm-svn: 321636
2018-01-02 05:47:42 +00:00
Simon Pilgrim
430dbb9fd8 [ValueTracking] Don't assume shift values are in range
Reduced (as best I could...) from oss-fuzz #4857 test case

llvm-svn: 321634
2018-01-01 22:44:59 +00:00
Benjamin Kramer
32a4f8ce12 Use phi ranges to simplify code. No functionality change intended.
llvm-svn: 321585
2017-12-30 15:27:33 +00:00
Philip Reames
4aa599e067 [instsimplify] consistently handle undef and out of bound indices for insertelement and extractelement
In one case, we were handling out of bounds, but not undef indices.  In the other, we were handling undef (with the comment making the analogy to out of bounds), but not out of bounds.  Be consistent and treat both undef and constant out of bounds indices as producing undefined results.

As a side effect, this also protects instcombine from having to handle large constant indices as we always simplify first.

llvm-svn: 321575
2017-12-30 05:54:22 +00:00
Max Kazantsev
185d475c7b [SCEV] Missing depth propagation in recursive call
llvm-svn: 321550
2017-12-29 08:44:32 +00:00
Guozhi Wei
9258c8ca8a Revert r321377, it causes regression to https://reviews.llvm.org/P8055.
llvm-svn: 321528
2017-12-28 17:02:34 +00:00
Benjamin Kramer
cf82ff23c4 Avoid int to string conversion in Twine or raw_ostream contexts.
Some output changes from uppercase hex to lowercase hex, no other functionality change intended.

llvm-svn: 321526
2017-12-28 16:58:54 +00:00
Reid Kleckner
a53c97833b Revert "[memcpyopt] Teach memcpyopt to optimize across basic blocks"
This reverts r321138. It seems there are still underlying issues with
memdep. PR35519 seems to still be present if debug info is enabled. We
end up losing a memcpy. Somehow during store to memset merging, we
insert the memset after the memcpy or fail to update the memdep analysis
to account for the newly inserted memset of a pair.

Reduced test case:

  #include <assert.h>
  #include <stdio.h>
  #include <string>
  #include <utility>
  #include <vector>

  void do_push_back(
      std::vector<std::pair<std::string, std::vector<std::string>>>* crls) {
    crls->push_back(std::make_pair(std::string(), std::vector<std::string>()));
  }

  int __attribute__((optnone)) main() {
    // Put some data in the vector and then remove it so we take the push_back
    // fast path.
    std::vector<std::pair<std::string, std::vector<std::string>>> crl_set;
    crl_set.push_back({"asdf", {}});
    crl_set.pop_back();
    printf("first word in vector storage: %p\n", *(void**)crl_set.data());

    // Do the push_back which may fail to initialize the data.
    do_push_back(&crl_set);
    auto* first = &crl_set.back().first;
    printf("first word in vector storage (should be zero): %p\n",
           *(void**)crl_set.data());
    assert(first->empty());
    puts("ok");
  }

Compile with libc++, enable optimizations, and enable debug info:
$ clang++ -stdlib=libc++ -g -O2 t.cpp -o t.exe -Wl,-rpath=llvm/build/lib

This program will assert with this change.

llvm-svn: 321510
2017-12-28 05:10:33 +00:00