We may be in a situation where the icmps might not be near each other in
a tree of or instructions. Try to dig out related compare instructions
and see if they combine.
N.B. This won't fire on deep trees of compares because rewritting the
tree might end up creating a net increase of IR. We may have to resort
to something more sophisticated if this is a real problem.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222928 91177308-0d34-0410-b5e6-96231b3b80d8
This restores our ability to optimize:
(X & C) == 0 ? X ^ C : X into X | C
(X & C) != 0 ? X ^ C : X into X & ~C
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222871 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r210006, it miscompiled libapr which is used in who
knows how many projects.
A test has been added to ensure that we don't regress again.
I'll work on a rewrite of what the optimization was trying to do later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222856 91177308-0d34-0410-b5e6-96231b3b80d8
stored rather than the pointer type.
This change is analogous to r220138 which changed the canonicalization
for loads. The rationale is the same: memory does not have a type,
operations (and thus the values they produce) have a type. We should
match that type as closely as possible rather than reading some form of
semantics into the pointer type.
With this change, loads and stores should no longer be made with
nonsensical types for the values that tehy load and store. This is
particularly important when trying to match specific loaded and stored
types in the process of doing other instcombines, which is what led me
down this twisty maze of miscanonicalization.
I've put quite some effort into looking through IR to find places where
LLVM's optimizer was being unreasonably conservative in the face of
mismatched load and store types, however it is possible (let's say,
likely!) I have missed some. If you see regressions here, or from
r220138, the likely cause is some part of LLVM failing to cope with load
and store types differing. Test cases appreciated, it is important that
we root all of these out of LLVM.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222748 91177308-0d34-0410-b5e6-96231b3b80d8
clearly only exactly equal width ptrtoint and inttoptr casts are no-op
casts, it says so right there in the langref. Make the code agree.
Original log from r220277:
Teach the load analysis to allow finding available values which require
inttoptr or ptrtoint cast provided there is datalayout available.
Eventually, the datalayout can just be required but in practice it will
always be there today.
To go with the ability to expose available values requiring a ptrtoint
or inttoptr cast, helpers are added to perform one of these three casts.
These smarts are necessary to finish canonicalizing loads and stores to
the operational type requirements without regressing fundamental
combines.
I've added some test cases. These should actually improve as the load
combining and store combining improves, but they may fundamentally be
highlighting some missing combines for select in addition to exercising
the specific added logic to load analysis.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222739 91177308-0d34-0410-b5e6-96231b3b80d8
We would create an instruction but not inserting it.
Not inserting the unused instruction would lead us to verification
failure.
This fixes PR21653.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222659 91177308-0d34-0410-b5e6-96231b3b80d8
We tried to get the result of DataLayout::getLargestLegalIntTypeSize but
we didn't have a DataLayout. This resulted in opt crashing.
This fixes PR21651.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222645 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes the self-host fail. Note that this commit activates dominator
analysis in the combiner by default (like the original commit did).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222590 91177308-0d34-0410-b5e6-96231b3b80d8
This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.
This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222334 91177308-0d34-0410-b5e6-96231b3b80d8
We would attempt to replace an frem's operand with the same operand.
This would cause InstCombine to think real work was done, causing
InstCombine to enter an infinite loop.
This fixes the second part of PR21576.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222265 91177308-0d34-0410-b5e6-96231b3b80d8
It is impossible for (x & INT_MAX) == 0 && x == INT_MAX to ever be true.
While this sort of reasoning should normally live in InstSimplify,
the machinery that derives this result is not trivial to split out.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222230 91177308-0d34-0410-b5e6-96231b3b80d8
We would attempt to replace a fptrunc of an frem with an identical
fptrunc. This would cause the new fptrunc to be added to the worklist.
Of course, this results in an infinite loop because we will keep
visiting the newly created fptruncs.
This fixes PR21576.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222040 91177308-0d34-0410-b5e6-96231b3b80d8
This patch enables the vec_vsx_ld and vec_vsx_st intrinsics for
PowerPC, which provide programmer access to the lxvd2x, lxvw4x,
stxvd2x, and stxvw4x instructions.
New LLVM intrinsics are provided to represent these four instructions
in IntrinsicsPowerPC.td. These are patterned after the similar
intrinsics for lvx and stvx (Altivec). In PPCInstrVSX.td, these
intrinsics are tied to the code gen patterns, with additional patterns
to allow plain vanilla loads and stores to still generate these
instructions.
At -O1 and higher the intrinsics are immediately converted to loads
and stores in InstCombineCalls.cpp. This will open up more
optimization opportunities while still allowing the correct
instructions to be generated. (Similar code exists for aligned
Altivec loads and stores.)
The new intrinsics are added to the code that checks for consecutive
loads and stores in PPCISelLowering.cpp, as well as to
PPCTargetLowering::getTgtMemIntrinsic().
There's a new test to verify the correct instructions are generated.
The loads and stores tend to be reordered, so the test just counts
their number. It runs at -O2, as it's not very effective to test this
at -O0, when many unnecessary loads and stores are generated.
I ended up having to modify vsx-fma-m.ll. It turns out this test case
is slightly unreliable, but I don't know a good way to prevent
problems with it. The xvmaddmdp instructions read and write the same
register, which is one of the multiplicands. Commutativity allows
either to be chosen. If the FMAs are reordered differently than
expected by the test, the register assignment can be different as a
result. Hopefully this doesn't change often.
There is a companion patch for Clang.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221767 91177308-0d34-0410-b5e6-96231b3b80d8
We currently have two ways of informing the optimizer that the result of a load is never null: metadata and assume. This change converts the second in to the former. This avoids a need to implement optimizations using both forms.
We should probably extend this basic idea to metadata of other forms; in particular, range metadata. We view is that assumes should be considered a "last resort" for when there isn't a more canonical way to represent something.
Reviewed by: Hal
Differential Revision: http://reviews.llvm.org/D5951
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221737 91177308-0d34-0410-b5e6-96231b3b80d8
Instead, we're going to separate metadata from the Value hierarchy. See
PR21532.
This reverts commit r221375.
This reverts commit r221373.
This reverts commit r221359.
This reverts commit r221167.
This reverts commit r221027.
This reverts commit r221024.
This reverts commit r221023.
This reverts commit r220995.
This reverts commit r220994.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221711 91177308-0d34-0410-b5e6-96231b3b80d8
Comparing the result of a cmpxchg instruction can be replaced with an
extractvalue of the cmpxchg success indicator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221498 91177308-0d34-0410-b5e6-96231b3b80d8
change LoopSimplifyPass to be !isCFGOnly. The motivation for the earlier patch
(r221223) was that LoopSimplify is not preserved by instcombine though
setPreservesCFG indicates that it is. This change fixes the issue
by making setPreservesCFG no longer imply LoopSimplifyPass, and is therefore less
invasive.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221311 91177308-0d34-0410-b5e6-96231b3b80d8
preserve LoopSimplify because instcombine may replace branch predicates
with undef which loop simplify then replaces with always exit. Replace
setPreservesCFG with the more constrained preservation of DomTree and
LoopInfo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221223 91177308-0d34-0410-b5e6-96231b3b80d8
FoldOpIntoPhi could create an infinite loop if the PHI could potentially
reach a BB it was considering inserting instructions into. The
instructions it would insert would eventually lead to other combines
firing which would, again, lead to FoldOpIntoPhi firing.
The solution is to handicap FoldOpIntoPhi so that it doesn't attempt to
insert instructions that the PHI might reach.
This fixes PR21377.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221187 91177308-0d34-0410-b5e6-96231b3b80d8
m_ZExt might bind against a ConstantExpr instead of an Instruction.
Assuming this, using cast<Instruction>, results in InstCombine crashing.
Instead, introduce ZExtOperator to bridge both Instruction and
ConstantExpr ZExts.
This fixes PR21445.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221069 91177308-0d34-0410-b5e6-96231b3b80d8
This can happen pretty often in code that looks like:
int foo = bar - 1;
if (foo < 0)
do stuff
In this case, bar < 1 is an equivalent condition.
This transform requires that the add instruction be annotated with nsw.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221045 91177308-0d34-0410-b5e6-96231b3b80d8
Change `Instruction::getAllMetadata()` to modify a vector of `Value`
instead of `MDNode` and update call sites. This is part of PR21433.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221027 91177308-0d34-0410-b5e6-96231b3b80d8
Change `Instruction::getMetadata()` to return `Value` as part of
PR21433.
Update most callers to use `Instruction::getMDNode()`, which wraps the
result in a `cast_or_null<MDNode>`.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221024 91177308-0d34-0410-b5e6-96231b3b80d8
An icmp may have pointer arguments, it isn't limited to integers or
vectors of integers.
This fixes PR21388.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220664 91177308-0d34-0410-b5e6-96231b3b80d8
These asserts can trigger if the worklist iteration order is
sufficiently unlucky. Instead of adding special case logic to handle
these edge conditions, just bail out on trying to transform them:
InstSimplify will get them when it reaches them on the worklist.
This fixes PR21378.
N.B. No test case is included because any test would rely on the
fragile worklist iteration order.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220612 91177308-0d34-0410-b5e6-96231b3b80d8
This patch removes a chunk of special case logic for folding
(float)sqrt((double)x) -> sqrtf(x)
in InstCombineCasts and handles it in the mainstream path of SimplifyLibCalls.
No functional change intended, but I loosened the restriction on the existing
sqrt testcases to allow for this optimization even without unsafe-fp-math because
that's the existing behavior.
I also added a missing test case for not shrinking the llvm.sqrt.f64 intrinsic
in case the result is used as a double.
Differential Revision: http://reviews.llvm.org/D5919
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220514 91177308-0d34-0410-b5e6-96231b3b80d8
This invariant is enforced in Value::replaceAllUsesWith, thus it seems
logical to apply it also to ValueHandles. This commit fixes InstCombine
to not trigger the assertion during the removal of constant bitcasts in
call instructions.
Differential Revision: http://reviews.llvm.org/D5828
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220468 91177308-0d34-0410-b5e6-96231b3b80d8
When a call to a double-precision libm function has fast-math semantics
(via function attribute for now because there is no IR-level FMF on calls),
we can avoid fpext/fptrunc operations and use the float version of the call
if the input and output are both float.
We already do this optimization using a command-line option; this patch just
adds the ability for fast-math to use the existing functionality.
I moved the cl::opt from InstructionCombining into SimplifyLibCalls because
it's only ever used internally to that class.
Modified the existing test cases to use the unsafe-fp-math attribute rather
than repeating all tests.
This patch should solve: http://llvm.org/bugs/show_bug.cgi?id=17850
Differential Revision: http://reviews.llvm.org/D5893
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220390 91177308-0d34-0410-b5e6-96231b3b80d8
These are named following the IEEE-754 names for these
functions, rather than the libm fmin / fmax to avoid
possible ambiguities. Some languages may implement something
resembling fmin / fmax which return NaN if either operand is
to propagate errors. These implement the IEEE-754 semantics
of returning the other operand if either is a NaN representing
missing data.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220341 91177308-0d34-0410-b5e6-96231b3b80d8
When changing the type of a load in Chandler's recent InstCombine changes, we can preserve the new 'nonnull' metadata.
I considered adding an assert since 'nonnull' is only valid on pointer types, but casting a pointer to a non-pointer would involve more than a bitcast anyways. If someone extends this transform to handle more than bitcasts, the verifier will report the malformed IR, so a separate assertion isn't needed. Also, the fpmath flags would have the same problem.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220324 91177308-0d34-0410-b5e6-96231b3b80d8
This function was complicated by the fact that it tried to perform
canonicalizations that were already preformed by InstSimplify. Remove
this extra code and move the tests over to InstSimplify. Add asserts to
make sure our preconditions hold before we make any assumptions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220314 91177308-0d34-0410-b5e6-96231b3b80d8
