If we fold a branch/switch to an unconditional branch to another dead block we
replace the branch with unreachable, to avoid attempting to fold the
unconditional branch.
Reviewers: davide, efriedma, mssimpso, jdoerfert
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D61300
llvm-svn: 360232
(X | C1) + C2 --> (X | C1) ^ C1 iff (C1 == -C2)
I verified the correctness using Alive:
https://rise4fun.com/Alive/YNV
This transform enables the following transform that already exists in
instcombine:
(X | Y) ^ Y --> X & ~Y
As a result, the full expected transform is:
(X | C1) + C2 --> X & ~C1 iff (C1 == -C2)
There already exists the transform in the sub case:
(X | Y) - Y --> X & ~Y
However this does not trigger in the case where Y is constant due to an earlier
transform:
X - (-C) --> X + C
With this new add fold, both the add and sub constant cases are handled.
Patch by Chris Dawson.
Differential Revision: https://reviews.llvm.org/D61517
llvm-svn: 360185
Fundamentally/generally, we should not have to rely on bailouts/crippling of
folds. In this particular case, I think we always recognize the inverted
predicate min/max pattern, so there should not be any loss of optimization.
Codegen looks better because we are eliminating an fneg.
llvm-svn: 360180
Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024
The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:
A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.
In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.
Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel
Reviewed By: hfinkel
Subscribers: bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits
Tags: #llvm, #debug-info
Differential Revision: https://reviews.llvm.org/D60831
llvm-svn: 360162
Summary:
Currently we express umin as `~umax(~x, ~y)`. However, this becomes
a problem for operands in non-integral pointer spaces, because `~x`
is not something we can compute for `x` non-integral. However, since
comparisons are generally still allowed, we are actually able to
express `umin(x, y)` directly as long as we don't try to express is
as a umax. Support this by adding an explicit umin/smin representation
to SCEV. We do this by factoring the existing getUMax/getSMax functions
into a new function that does all four. The previous two functions were
largely identical.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D50167
llvm-svn: 360159
This reverts r357452 (git commit 21eb771dcb).
This was causing strange optimization-related test failures on an internal test. Will followup with more details offline.
llvm-svn: 360086
We don't always get this:
Cond ? -X : -Y --> -(Cond ? X : Y)
...even with the legacy IR form of fneg in the case with extra uses,
and we miss matching with the newer 'fneg' instruction because we
are expecting binops through the rest of the path.
Differential Revision: https://reviews.llvm.org/D61604
llvm-svn: 360075
Optimization pass lib/Transforms/IPO/GlobalOpt.cpp needs to insert
DW_OP_deref_size instead of DW_OP_deref to be compatible with big-endian
targets for same reasons as in D59687.
Differential Revision: https://reviews.llvm.org/D60611
llvm-svn: 360013
This is a subset of the original commit from rL359879
which was reverted because it could crash when using the 'RemovedInstructions'
structure that enables delayed deletion of dead instructions. The motivating
compile-time win does not require that change though. We should get most of
that win from this change alone.
Using/updating a dominator tree to match math overflow patterns may be very
expensive in compile-time (because of the way CGP uses a DT), so just handle
the single-block case.
See post-commit thread for rL354298 for more details:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190422/646276.html
Differential Revision: https://reviews.llvm.org/D61075
llvm-svn: 359969
Using/updating a dominator tree to match math overflow patterns may be very
expensive in compile-time (because of the way CGP uses a DT), so just handle
the single-block case.
Also, we were restarting the iterator loops when doing the overflow intrinsic
transforms by marking the dominator tree for update. That was done to prevent
iterating over a removed instruction. But we can postpone the deletion using
the existing "RemovedInsts" structure, and that means we don't need to update
the DT.
See post-commit thread for rL354298 for more details:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190422/646276.html
Differential Revision: https://reviews.llvm.org/D61075
llvm-svn: 359879
Summary:
Inalloca parameters require special handling in some optimizations.
This change causes globalopt to strip the inalloca attribute from
function parameters when it is safe to do so, removes the special
handling for inallocas from argpromotion, and replaces it with a
simple check that causes argpromotion to skip functions that receive
inallocas (for when the pass is invoked on code that didn't run
through globalopt first). This also avoids a case where argpromotion
would incorrectly try to pass an inalloca in a register.
Fixes PR41658.
Reviewers: rnk, efriedma
Reviewed By: rnk
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61286
llvm-svn: 359743
Summary: Fix a transformation bug where two scopes share a common instrution to hoist.
Reviewers: davidxl
Reviewed By: davidxl
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61405
llvm-svn: 359736
Summary:
Triple components in `XFAIL` lines are tested against the target triple.
Various tests that are expected to fail on big-endian hosts are marked
as being `XFAIL` for big-endian targets. This patch corrects these tests
by having them test against a new `host-byteorder-big-endian` feature.
Reviewers: xingxue, sfertile, jasonliu
Reviewed By: xingxue
Subscribers: jvesely, nhaehnle, fedor.sergeev, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60551
llvm-svn: 359689
The demanded elts rules introduced for GEPs in https://reviews.llvm.org/rL356293 replaced vector constants with undefs (by design). It turns out that the LangRef disallows such cases when indexing structs. The right fix is probably to relax the langref requirement, and update other passes to expect the result, but for the moment, limit the transform to avoid compiler crashes.
This should fix https://bugs.llvm.org/show_bug.cgi?id=41624.
llvm-svn: 359633
Summary:
Match NewPassManager behavior: add option for interleaved loops in the
old pass manager, and use that instead of the flag used to disable loop unroll.
No changes in the defaults.
Reviewers: chandlerc
Subscribers: mehdi_amini, jlebar, dmgreen, hsaito, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61030
llvm-svn: 359615
The code in this test is not vectorized by SLP because its operand reordering cannot look beyond the immediate predecessors.
This will get fixed in a follow-up patch that introduces the look-ahead operand reordering heuristic.
Committed on behalf of @vporpo (Vasileios Porpodas)
Differential Revision: https://reviews.llvm.org/D61283
llvm-svn: 359553
This change aims at making the file format be compatible with the
way LLVM handles command line options.
Differential Revision: https://reviews.llvm.org/D60970
llvm-svn: 359462
it keeps track of becomes too large
ARC optimizer does a top-down and a bottom-up traversal of the whole
function to pair up retain and release instructions and remove them.
This can be expensive if the number of instructions in the function and
pointer states it tracks are large since it has to look at each pointer
state and determine whether the instruction being visited can
potentially use the pointer.
This patch adds a command line option that sets a limit to the number of
pointers it tracks.
rdar://problem/49477063
Differential Revision: https://reviews.llvm.org/D61100
llvm-svn: 359226
When evaluating a store through a bitcast, the evaluator tries to move the
bitcast from the pointer onto the stored value. If the cast is invalid, it
tries to "introspect" the type to get a valid cast by obtaining a pointer to
the initial element (if the type is nested, this may require walking several
initial elements).
In some situations it is possible to get a bitcast on a load (e.g. with
unions, where the bitcast may not be the same type as the store). However,
equivalent logic to the store to introspect the type is missing. This patch
add this logic.
Note, when developing the patch I was unhappy with adding similar logic
directly to the load case as it could get out of step. Instead, I have
abstracted the "introspection" into a helper function, with the specifics
being handled by a passed-in lambda function.
Differential Revision: https://reviews.llvm.org/D60793
llvm-svn: 359205
Summary:
When refactoring vectorization flags, vectorization was disabled by default in the new pass manager.
This patch re-enables is for both managers, and changes the assumptions opt makes, based on the new defaults.
Comments in opt.cpp should clarify the intended use of all flags to enable/disable vectorization.
Reviewers: chandlerc, jgorbe
Subscribers: jlebar, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61091
llvm-svn: 359167
Summary: The code did not check if operand was undef before casting it to Instruction.
Reviewers: RKSimon, ABataev, dtemirbulatov
Reviewed By: ABataev
Subscribers: uabelho
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61024
llvm-svn: 359136
DominatorTree::dominate.
ARC contract pass has an optimization that replaces the uses of the
argument of an ObjC runtime function call with the call result.
For example:
; Before optimization
%1 = tail call i8* @foo1()
%2 = tail call i8* @llvm.objc.retainAutoreleasedReturnValue(i8* %1)
store i8* %1, i8** @g0, align 8
; After optimization
%1 = tail call i8* @foo1()
%2 = tail call i8* @llvm.objc.retainAutoreleasedReturnValue(i8* %1)
store i8* %2, i8** @g0, align 8 // %1 is replaced with %2
Before replacing the argument use, DominatorTree::dominate is called to
determine whether the user instruction is dominated by the ObjC runtime
function call instruction. The call to DominatorTree::dominate can be
expensive if the two instructions belong to the same basic block and the
size of the basic block is large. This patch checks the basic block size
and just bails out if the size exceeds the limit set by command line
option "arc-contract-max-bb-size".
rdar://problem/49477063
Differential Revision: https://reviews.llvm.org/D60900
llvm-svn: 359027
If we have a masked.load from a location we know to be dereferenceable, we can simply issue a speculative unconditional load against that address. The key advantage is that it produces IR which is well understood by the optimizer. The select (cnd, load, passthrough) form produced should be pattern matchable back to hardware predication if profitable.
Differential Revision: https://reviews.llvm.org/D59703
llvm-svn: 359000
In some circumstances we can end up with setup costs that are very complex to
compute, even though the scevs are not very complex to create. This can also
lead to setupcosts that are calculated to be exactly -1, which LSR treats as an
invalid cost. This patch puts a limit on the recursion depth for setup cost to
prevent them taking too long.
Thanks to @reames for the report and test case.
Differential Revision: https://reviews.llvm.org/D60944
llvm-svn: 358958
If we have a store to a piece of memory which is known constant, then we know the store must be storing back the same value. As a result, the store (or memset, or memmove) must either be down a dead path, or a noop. In either case, it is valid to simply remove the store.
The motivating case for this involves a memmove to a buffer which is constant down a path which is dynamically dead.
Note that I'm choosing to implement the less aggressive of two possible semantics here. We could simply say that the store *is undefined*, and prune the path. Consensus in the review was that the more aggressive form might be a good follow on change at a later date.
Differential Revision: https://reviews.llvm.org/D60659
llvm-svn: 358919
Florian Hahn