Since r230724 ("Skip promotable allocas to improve performance at -O0"), there is a regression in the generated debug info for those non-instrumented variables. When inspecting such a variable's value in LLDB, you often get garbage instead of the actual value. ASan instrumentation is inserted before the creation of the non-instrumented alloca. The only allocas that are considered standard stack variables are the ones declared in the first basic-block, but the initial instrumentation setup in the function breaks that invariant.
This patch makes sure uninstrumented allocas stay in the first BB.
Differential Revision: http://reviews.llvm.org/D11179
llvm-svn: 242510
Internalizing an individual comdat group member without also internalizing
the other members of the comdat can break comdat semantics. For example,
if a module contains a reference to an internalized comdat member, and the
linker chooses a comdat group from a different object file, this will break
the reference to the internalized member.
This change causes the internalizer to only internalize comdat members if all
other members of the comdat are not externally visible. Once a comdat group
has been fully internalized, there is no need to apply comdat rules to its
members; later optimization passes (e.g. globaldce) can legally drop individual
members of the comdat. So we drop the comdat attribute from all comdat members.
Differential Revision: http://reviews.llvm.org/D10679
llvm-svn: 242423
This new wrapper pass is useful when we want to do branch probability analysis conditionally (e.g. only in PGO mode) but don't want to add one more pass dependence.
http://reviews.llvm.org/D11241
llvm-svn: 242349
Summary:
This is a trivial code change with no functionality effect.
When LoopUnswitch determines trivial unswitch condition, it checks whether the loop header's terminator instruction is a branch instruction or switch instruction since trivial unswitch condition can only apply to these two instruction types. The current code does not fail the check directly on other instruction types, but check the nullness of LoopExitBB variable instead. The added else clause makes the check fail immediately on other instruction types and makes the code more obvious.
Reviewers: reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11239
llvm-svn: 242345
Self-referential constants containing references to a merged function
no longer cause the MergeFunctions pass to infinite loop. Also adds a
reproduction IR which would otherwise fail, which was isolated from a similar
issue in Chromium.
Author: jrkoenig
Reviewers: nlewycky, jfb
Subscribers: llvm-commits, nlewycky, jfb
Differential Revision: http://reviews.llvm.org/D11208
llvm-svn: 242337
During estimation of unrolling effect we should be able to propagate
constants through casts.
Differential Revision: http://reviews.llvm.org/D10207
llvm-svn: 242257
This is useful when we want to do block frequency analysis
conditionally (e.g. only in PGO mode) but don't want to add
one more pass dependence.
Patch by congh.
Approved by dexonsmith.
Differential Revision: http://reviews.llvm.org/D11196
llvm-svn: 242248
I am planning to add more nested classes inside RuntimePointerCheck so
all these triple-nesting would be hard to follow.
Also rename it to RuntimePointerChecking (i.e. append 'ing').
llvm-svn: 242218
Sometimes an incidentally created instruction can duplicate a Value used
elsewhere. It then often doesn't end up in the leader table. If it's later
removed, we attempt to remove it from the leader table and segfault.
Instead we should just ignore the removal request, which won't cause any
problems. The reverse situation, where the original instruction is replaced by
the new one (which you might think could leave the leader table empty) cannot
occur, because the incidental instruction will never be found in the first
place.
llvm-svn: 242199
Volatile loads and stores are made visible in global state regardless of
what memory is involved. It is not correct to disregard the ordering
and synchronization scope because it is possible to synchronize with
memory operations performed by hardware.
This partially addresses PR23737.
llvm-svn: 242126
Previously we would refrain from attempting to increase the linkage of
available_externally globals because they were considered weak for the
linker. Now they are treated more like a declaration instead of a weak
definition.
This was causing SSE alignment faults in Chromuim, when some code
assumed it could increase the alignment of a dllimported global that it
didn't control. http://crbug.com/509256
llvm-svn: 242091
When spotting that a loop can use ctpop, we were incorrectly replacing all uses of a value with a value derived from ctpop.
The bug here was exposed because we were replacing a use prior to the ctpop with the ctpop value and so we have a use before def, i.e., we changed
%tobool.5 = icmp ne i32 %num, 0
store i1 %tobool.5, i1* %ptr
br i1 %tobool.5, label %for.body.lr.ph, label %for.end
to
store i1 %1, i1* %ptr
%0 = call i32 @llvm.ctpop.i32(i32 %num)
%1 = icmp ne i32 %0, 0
br i1 %1, label %for.body.lr.ph, label %for.end
Even if we inserted the ctpop so that it dominates the store here, that would still be incorrect. The store doesn’t want the result of ctpop.
The fix is very simple, and involves replacing only the branch condition with the ctpop instead of all uses.
Reviewed by Hal Finkel.
llvm-svn: 242068
Enable runtime unrolling for loops with unroll count metadata ("#pragma unroll N")
and a runtime trip count. Also, do not unroll loops with unroll full metadata if the
loop has a runtime loop count. Previously, such loops would be unrolled with a
very large threshold (pragma-unroll-threshold) if runtime unrolled happened to be
enabled resulting in a very large (and likely unwise) unroll factor.
llvm-svn: 242047
Passes should never modify it, just use the const version. While there
reduce copying in LoopInterchange. No functional change intended.
llvm-svn: 242041
There is no suitable basic block to sink instructions in loops without
exits. The only way an instruction in a loop without exits can be used
is as an incoming value to a PHI. In such cases, the incoming block for
the corresponding value is unreachable.
This fixes PR24013.
Differential Revision: http://reviews.llvm.org/D10903
llvm-svn: 241987
The following functions are moved from the LoopVectorizer to VectorUtils:
- getGEPInductionOperand
- stripGetElementPtr
- getUniqueCastUse
- getStrideFromPointer
These used to be static functions in LoopVectorize, but will also be used by
the upcoming loop versioning LICM transformation.
Patch by Ashutosh Nema!
llvm-svn: 241980
No in-tree alias analysis used this facility, and it was not called in
any particularly rigorous way, so it seems unlikely to be correct.
Note that one of the only stateful AA implementations in-tree,
GlobalsModRef is completely broken currently (and any AA passes like it
are equally broken) because Module AA passes are not effectively
invalidated when a function pass that fails to update the AA stack runs.
Ultimately, it doesn't seem like we know how we want to build stateful
AA, and until then trying to support and maintain correctness for an
untested API is essentially impossible. To that end, I'm planning to rip
out all of the update API. It can return if and when we need it and know
how to build it on top of the new pass manager and as part of *tested*
stateful AA implementations in the tree.
Differential Revision: http://reviews.llvm.org/D10889
llvm-svn: 241975
Summary:
Following the discussion on r241884, it's more reasonable to assume that a
target has no vector registers by default instead of letting every such
target overrides getNumberOfRegisters.
Therefore, this patch modifies BasicTTIImpl::getNumberOfRegisters to
return 0 when Vector is true, and partially reverts r241884 which
modifies NVPTXTTIImpl::getNumberOfRegisters.
It also fixes a performance bug in LoopVectorizer. Even if a target has
no vector registers, vectorization may still help ILP. So, we need both
checks to be false before disabling loop vectorization all together.
Reviewers: hfinkel
Subscribers: llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D11108
llvm-svn: 241942
Summary:
The class will obviously need improvement down the road. For one, there
is no reason that addPHINodes would have to be exposed like that. I
will make this and other improvements in follow-up patches.
The main goal is to be able to share this functionality. The
LoopLoadElimination pass I am working on needs it too. Later we can
move other clients as well (LV and Ashutosh's LICMVer).
Reviewers: hfinkel, ashutosh.nema
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10577
llvm-svn: 241932
Summary:
This makes them available to the LoopVersioning class as that is moved
to its own module in the next patch.
Reviewers: ashutosh.nema, hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10576
llvm-svn: 241931
After changes in rL231820 loop re-rotation is performed even in -Oz mode. Since loop rotation is disabled for -Oz, it seems loop re-rotation should be disabled too.
Differential Revision: http://reviews.llvm.org/D10961
llvm-svn: 241897
Summary:
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support. Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.
Reviewers: rnk, JosephTremoulet, reames, nlewycky, rjmccall
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11041
llvm-svn: 241888
Not doing this can lead to misoptimizations down the line, e.g. because
of range metadata on the replacing load excluding values that are valid
for the load that is being replaced.
llvm-svn: 241886
Summary:
In RewriteLoopExitValues, before expanding out an SCEV expression using
SCEVExpander, try to see if an existing LLVM IR expression already
computes the value we're interested in. If so use that existing
expression.
Apart from reducing IndVars' reliance on the rest of the compilation
pipeline, this also prevents IndVars from concluding some expressions as
"high cost" when they're not. For instance,
`InductiveRangeCheckElimination` often emits code of the following form:
```
len = umin(len_A, len_B)
loop:
...
if (i++ < len)
goto loop
outside_loop:
use(i)
```
`SCEVExpander` refuses to rewrite the use of `i` in `outside_loop`,
since it thinks the value of `i` on loop exit, `len`, is a high cost
expansion since it contains an `umax` in it. With this change,
`IndVars` can see that it can re-use `len` instead of creating a new
expression to compute `umin(len_A, len_B)`.
I considered putting this cleverness in `SCEVExpander`, but I was
worried that it may then have a deterimental effect on other passes
that use it. So I decided it was better to just do this in the one
place where it seems like an obviously good idea, with the intent of
generalizing later if needed.
Reviewers: atrick, reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10782
llvm-svn: 241838
Place all code corresponding to a run-time check in one place.
Previously we generated some code, then proceeded to a next check, then
finished the code for the first check (like splitting blocks and
generating branches). Now the code for generating a check is
self-contained.
llvm-svn: 241741
Summary:
Initially, these intrinsics seemed like part of a family of "frame"
related intrinsics, but now I think that's more confusing than helpful.
Initially, the LangRef specified that this would create a new kind of
allocation that would be allocated at a fixed offset from the frame
pointer (EBP/RBP). We ended up dropping that design, and leaving the
stack frame layout alone.
These intrinsics are really about sharing local stack allocations, not
frame pointers. I intend to go further and add an `llvm.localaddress()`
intrinsic that returns whatever register (EBP, ESI, ESP, RBX) is being
used to address locals, which should not be confused with the frame
pointer.
Naming suggestions at this point are welcome, I'm happy to re-run sed.
Reviewers: majnemer, nicholas
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11011
llvm-svn: 241633
This reverts commit r241602. We had a latent bug in SCCP where we would
make a basic block empty and then proceed to ask questions about it's
terminator.
llvm-svn: 241616
This change includes a fix for https://code.google.com/p/chromium/issues/detail?id=499508#c3,
which required updating the visibility for symbols with eliminated definitions.
--Original Commit Message--
Add new EliminateAvailableExternally module pass, which is performed in
O2 compiles just before GlobalDCE, unless we are preparing for LTO.
This pass eliminates available externally globals (turning them into
declarations), regardless of whether they are dead/unreferenced, since
we are guaranteed to have a copy available elsewhere at link time.
This enables additional opportunities for GlobalDCE.
If we are preparing for LTO (e.g. a -flto -c compile), the pass is not
included as we want to preserve available externally functions for possible
link time inlining. The FE indicates whether we are doing an -flto compile
via the new PrepareForLTO flag on the PassManagerBuilder.
llvm-svn: 241466
Kuba Brecka