Canonicalizing 'x [+-] (-Constant * y)' is not a win if we don't *know*
we will open up CSE opportunities.
If the multiply was 'nsw', then negating 'y' requires us to clear the
'nsw' flag. If this is actually worth pursuing, it is probably more
appropriate to do so in GVN or EarlyCSE.
This fixes PR23675.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238397 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch made two improvements to NaryReassociate and the NVPTX pipeline
1. Run EarlyCSE/GVN after NaryReassociate to get rid of redundant common
expressions.
2. When adding an instruction to SeenExprs, maps both the SCEV before and after
reassociation to that instruction.
Test Plan: updated @reassociate_gep_nsw in nary-gep.ll
Reviewers: meheff, broune
Reviewed By: broune
Subscribers: dberlin, jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D9947
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238396 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes a bit I forgot in r238335. In addition to the data record and
the counter, we can also move the name of the counter to the comdat for
the associated function.
I'm also adding an IR test case to check that these three elements are
placed in the proper comdat.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238351 91177308-0d34-0410-b5e6-96231b3b80d8
Counter symbols created for linkonce functions are not discarded by ELF
linkers unless the symbols are placed in the same comdat section as its
associated function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238335 91177308-0d34-0410-b5e6-96231b3b80d8
Long ago, the poll insertion code assumed that the insertion site was a terminator. As a result, the entry selection code would split a basic block to ensure it could pass a terminator. The insertion code was updated quite a while ago - possibly before it ever landed upstream - but the now redundant work was never removed.
While I'm at it, remove a comment which doesn't apply to the upstreamed code.
NFC intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238254 91177308-0d34-0410-b5e6-96231b3b80d8
While working on another change, I noticed that the naming in this function was mildly deceptive. While fixing that, I took the oppurtunity to modernize some of the code. NFC intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238252 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In case of functions that have a pointer argument and only pass it to
each other, the function attributes pass deduces that the pointer should
get the readnone attribute, but fails to remove a readonly attribute
that may already have been present.
Reviewers: nlewycky
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9995
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238152 91177308-0d34-0410-b5e6-96231b3b80d8
lazily built.
Also, make it a much more generic SCEV cache, which today exposes only
a reduced GEP model description but could be extended in the future to
do other profitable caching of SCEV information.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238124 91177308-0d34-0410-b5e6-96231b3b80d8
This patch extends EarlyCSE to take advantage of the information that a controlling branch gives us about the value of a Value within this and dominated basic blocks. If the current block has a single predecessor with a controlling branch, we can infer what the branch condition must have been to execute this block. The actual change to support this is downright simple because EarlyCSE's existing scoped hash table logic deals with most of the complexity around merging.
The patch actually implements two optimizations.
1) The first is analogous to JumpThreading in that it enables EarlyCSE's CSE handling to fold branches which are exactly redundant due to a previous branch to branches on constants. (It doesn't actually replace the branch or change the CFG.) This is pretty clearly a win since it enables substantial CFG simplification before we start trying to inline.
2) The second is analogous to CVP in that it exploits the knowledge gained to replace dominated *uses* of the original value. EarlyCSE does not otherwise reason about specific uses, so this is the more arguable one. It does enable further simplication and constant folding within the rest of the visit by EarlyCSE.
In both cases, the added code only handles the easy dominance based case of each optimization. The general case is deferred to the existing passes.
Differential Revision: http://reviews.llvm.org/D9763
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238071 91177308-0d34-0410-b5e6-96231b3b80d8
InstCombine transforms A *nsw B +nsw A *nsw C to A *nsw (B + C).
This is incorrect -- e.g. if A = -1, B = 1, C = INT_SMAX. Then
nothing in the LHS overflows, but the multiplication in RHS overflows.
We need to first make sure that we won't multiple by INT_SMAX + 1.
Test case `add_of_mul` contributed by Sanjoy Das.
This fixes PR23635.
Differential Revision: http://reviews.llvm.org/D9629
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238066 91177308-0d34-0410-b5e6-96231b3b80d8
accumulating estimated cost, and other loop-centric logic from the logic
used to analyze instructions in a particular iteration.
This makes the visitor very narrow in scope -- all it does is visit
instructions, update a map of simplified values, and return whether it
is able to optimize away a particular instruction.
The two cost metrics are now returned as an optional struct. When the
optional is left unengaged, there is no information about the unrolled
cost of the loop, when it is engaged the cost metrics are available to
run against the thresholds.
No functionality changed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238033 91177308-0d34-0410-b5e6-96231b3b80d8
This change does a few things:
- Move some InstCombine transforms to InstSimplify
- Run SimplifyCall from within InstCombine::visitCallInst
- Teach InstSimplify to fold [us]mul_with_overflow(X, undef) to 0.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237995 91177308-0d34-0410-b5e6-96231b3b80d8
problem instead of suggesting doing something that is trivial to do but
incorrect given the current design of the libraries.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237994 91177308-0d34-0410-b5e6-96231b3b80d8
simplified model for use simulating each iteration into a separate
helper function that just returns the cache.
Building this cache had nothing to do with the rest of the unroll
analysis and so this removes an unnecessary coupling, etc. It should
also make it easier to think about the concept of providing fast cached
access to basic SCEV models as an orthogonal concept to the overall
unroll simulation.
I'd really like to see this kind of caching logic folded into SCEV
itself, it seems weird for us to provide it at this layer rather than
making repeated queries into SCEV fast all on their own.
No functionality changed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237993 91177308-0d34-0410-b5e6-96231b3b80d8
a single location.
This reduces code duplication a bit and will also pave the way for
a better separation between the visitation algorithm and the unroll
analysis.
No functionality changed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237990 91177308-0d34-0410-b5e6-96231b3b80d8
PR23608 pointed out that using the preheader to gain a context instruction isn't always legal because a loop might not have a preheader. When looking into that, I realized that using the preheader to determine legality for sinking is questionable at best. Given no test covers that case and the original commit didn't seem to intend it, I restructured the code to only ask context sensative queries for hoising of loads and stores. This is effectively a partial revert of 237593.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237985 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
x = &a[i];
y = &a[i + j];
=>
y = x + j;
along with some refactoring work such as extracting method
findClosestMatchingDominator.
Depends on D9786 which provides the ScalarEvolution::getGEPExpr interface.
Test Plan: nary-gep.ll
Reviewers: meheff, broune
Reviewed By: broune
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D9802
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237971 91177308-0d34-0410-b5e6-96231b3b80d8
A refactoring made @llvm.ssub.with.overflow.i32(i32 %X, i32 0) transform
into undef instead of %X.
This fixes PR23624.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237968 91177308-0d34-0410-b5e6-96231b3b80d8
In effect a partial revert of r237858, which was a dumb shortcut.
Looking at the dependencies of the destination should be the proper
fix: if the new memset would depend on anything other than itself,
the transformation isn't correct.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237874 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes PR23599, another miscompile introduced by r235232: when there is
another dependency on the destination of the created memset (i.e., the
part of the original destination that the memcpy doesn't depend on)
between the memcpy and the original memset, we would insert the created
memset after the memcpy, and thus after the other dependency.
Instead, insert the created memset right after the old one.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237858 91177308-0d34-0410-b5e6-96231b3b80d8
Make sure if we're truncating a constant that would then be sign extended
that the sign extension of the truncated constant is the same as the
original constant.
> Canonicalize min/max expressions correctly.
>
> This patch introduces a canonical form for min/max idioms where one operand
> is extended or truncated. This often happens when the other operand is a
> constant. For example:
>
> %1 = icmp slt i32 %a, i32 0
> %2 = sext i32 %a to i64
> %3 = select i1 %1, i64 %2, i64 0
>
> Would now be canonicalized into:
>
> %1 = icmp slt i32 %a, i32 0
> %2 = select i1 %1, i32 %a, i32 0
> %3 = sext i32 %2 to i64
>
> This builds upon a patch posted by David Majenemer
> (https://www.marc.info/?l=llvm-commits&m=143008038714141&w=2). That pass
> passively stopped instcombine from ruining canonical patterns. This
> patch additionally actively makes instcombine canonicalize too.
>
> Canonicalization of expressions involving a change in type from int->fp
> or fp->int are not yet implemented.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237821 91177308-0d34-0410-b5e6-96231b3b80d8
Now that Intrinsic::ID is a typed enum, we can forward declare it and so return it from this method.
This updates all users which were either using an unsigned to store it, or had a now unnecessary cast.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237810 91177308-0d34-0410-b5e6-96231b3b80d8
This change adds a new GC strategy for supporting the CoreCLR runtime.
This strategy is currently identical to Statepoint-example GC,
but is necessary for several upcoming changes specific to CoreCLR, such as:
1. Base-pointers not explicitly reported for interior pointers
2. Different format for stack-map encoding
3. Location of Safe-point polls: polls are only needed before loop-back edges and before tail-calls (not needed at function-entry)
4. Runtime specific handshake between calls to managed/unmanaged functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237753 91177308-0d34-0410-b5e6-96231b3b80d8
We were special casing a handful of intrinsics as not needing a safepoint before them. After running into another valid case - memset - I took a closer look and realized that almost no intrinsics need to have a safepoint poll before them. Restructure the code to make that apparent so that we stop hitting these bugs. The only intrinsics which need a safepoint poll before them are ones which can run arbitrary code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237744 91177308-0d34-0410-b5e6-96231b3b80d8
InstructionCombiningPass was added after LoopUnrollPass in r237395. Because
InstructionCombiningPass is strictly more powerful than InstructionSimplifierPass,
remove the unnecessary InstructionSimplifierPass.
Differential Revision: http://reviews.llvm.org/D9838
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237702 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: When PlaceSafepoints pass replaces old return result with gc_result from statepoint, it asserts that gc_result can not have preceding phis in its parent block. This is only true on invoke statepoint, which terminates the block and puts its result at the beginning of the normal successor block. Call statepoint does not terminate the block and thus its result is in the same block with it. There should be no restriction on whether there are phis or not.
Reviewers: reames, igor-laevsky
Reviewed By: igor-laevsky
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9803
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237597 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Allow hoisting of loads from values marked with dereferenceable_or_null
attribute. For values marked with the attribute perform
context-sensitive analysis to determine whether it's known-non-null or
not.
Patch by Artur Pilipenko!
Reviewers: hfinkel, sanjoy, reames
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9253
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237593 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This allows other passes (such as SLSR) to compute the SCEV expression for an
imaginary GEP.
Test Plan: no regression
Reviewers: atrick, sanjoy
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9786
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237589 91177308-0d34-0410-b5e6-96231b3b80d8
Don't replace a phi with an identical phi. This was done long ago to
"preserve" IVUsers analysis. The code has already called
SE->forgetValue(PN) so I see no purpose in creating a new value for
the phi.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237587 91177308-0d34-0410-b5e6-96231b3b80d8