Change isConsecutiveLoads to check that loads are non-volatile as this
is a requirement for any load merges. Propagate change to two callers.
Reviewers: RKSimon
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D18546
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When merging stores in DAGCombiner, add check to ensure that no
dependenices exist that would cause the construction of a cycle in our
DAG. This may happen if one store has a data dependence on another
instruction (e.g. a load) which itself has a (chain) dependence on
another store being merged. These stores cannot be merged safely and
doing so results in a cycle that is discovered in LegalizeDAG.
This test is only done in cases where Antialias analysis is used (UseAA)
as non-AA store merge candidates will be merged logically after all
loads which have been checked to not alias.
Reviewers: ahatanak, spatel, niravd, arsenm, hfinkel, tstellarAMD, jyknight
Subscribers: llvm-commits, tberghammer, danalbert, srhines
Differential Revision: http://reviews.llvm.org/D18336
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Found during fuzz testing - 32-bit x86 targets were legalizing a <2 x i1> compare result to <2 x i32> when <2 x i64> was expected.
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This re-applies r262886 with a fix for 32 bit platforms that have 8 byte
pointer alignment, effectively reverting r262892.
Original Message:
Currently some SDNode operands are malloc'd, some are stored inline in
subclasses of SDNode, and some are thrown into a BumpPtrAllocator.
This scheme is complex, inconsistent, and makes refactoring SDNodes
fairly difficult.
Instead, we can allocate all of the operands using an ArrayRecycler
that wraps a BumpPtrAllocator. This keeps the cache locality when
iterating operands, improves locality when iterating SDNodes without
looking at operands, and vastly simplifies the ownership semantics.
It also means we stop overallocating SDNodes by 2-3x and will make it
simpler to fix the rampant undefined behaviour we have in how we
mutate SDNodes from one kind to another (See llvm.org/pr26808).
This is NFC other than the changes in memory behaviour, and I ran some
LNT tests to make sure this didn't hurt compile time. Not many tests
changed: there were a couple of 1-2% regressions reported, but there
were more improvements (of up to 4%) than regressions.
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Looks like the largest SDNode is different between 32 and 64 bit now,
so this is breaking 32 bit bots. Reverting while I figure out a fix.
This reverts r262886.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262892 91177308-0d34-0410-b5e6-96231b3b80d8
Currently some SDNode operands are malloc'd, some are stored inline in
subclasses of SDNode, and some are thrown into a BumpPtrAllocator.
This scheme is complex, inconsistent, and makes refactoring SDNodes
fairly difficult.
Instead, we can allocate all of the operands using an ArrayRecycler
that wraps a BumpPtrAllocator. This keeps the cache locality when
iterating operands, improves locality when iterating SDNodes without
looking at operands, and vastly simplifies the ownership semantics.
It also means we stop overallocating SDNodes by 2-3x and will make it
simpler to fix the rampant undefined behaviour we have in how we
mutate SDNodes from one kind to another (See llvm.org/pr26808).
This is NFC other than the changes in memory behaviour, and I ran some
LNT tests to make sure this didn't hurt compile time. Not many tests
changed: there were a couple of 1-2% regressions reported, but there
were more improvements (of up to 4%) than regressions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262886 91177308-0d34-0410-b5e6-96231b3b80d8
The placement new calls here were all calling the allocation function
in RecyclingAllocator/Recycler for SDNode, instead of the function for
the specific subclass we were constructing.
Since this particular allocator always overallocates it more or less
worked, but would hide what we're actually doing from any memory
tools. Also, if you tried to change this allocator so something like a
BumpPtrAllocator or MallocAllocator, the compiler would crash horribly
all the time.
Part of llvm.org/PR26808.
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This was causing assertions later from using the wrong pointer
size with LDS operations. getOptimalMemOpType should also have
address space arguments later.
This avoids assertions in existing tests exposed by
a future commit.
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I missed == and != when I removed implicit conversions between iterators
and pointers in r252380 since they were defined outside ilist_iterator.
Since they depend on getNodePtrUnchecked(), they indirectly rely on UB.
This commit removes all uses of these operators. (I'll delete the
operators themselves in a separate commit so that it can be easily
reverted if necessary.)
There should be NFC here.
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The code change is simple enough: instead of attaching an anonymous SDLoc to splatted
vector constants, use the scalar constant's existing SDLoc since that is what is passed
into getConstant() as a param. But this changes instruction scheduling, so I'll explain
why that happens.
The motivation for this patch starts near:
http://reviews.llvm.org/rL258833
...x86's getZeroVector() could be similarly cleaned up and I thought it would be 'NFC'.
But when I made that change locally, several x86 codegen tests wiggled.
It turns out that the lack of SDLoc consistency in getConstant() changes the way
ScheduleDAGRRList behaves. This is because the SDLoc contains 'IROrder' and some DAG
scheduler algorithms use IROrder for tie-breaking.
Differential Revision: http://reviews.llvm.org/D16972
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I reinvented this functionality in http://reviews.llvm.org/D16828 because it was
hidden away as a static function. The changes in x86 are not based on a complete
audit. I suspect there are other possible uses there, and there are almost certainly
more potential users in other targets.
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This patch consists of two parts: a performance fix in DAGCombiner.cpp
and a correctness fix in SelectionDAG.cpp.
The test case tests the bug that's uncovered by the performance fix, and
fixed by the correctness fix.
The performance fix keeps the containers required by the
hasPredecessorHelper (which is a lazy DFS) and reuse them. Since
hasPredecessorHelper is called in a loop, the overall efficiency reduced
from O(n^2) to O(n), where n is the number of SDNodes.
The correctness fix keeps iterating the neighbor list even if it's time
to early return. It will return after finishing adding all neighbors to
Worklist, so that no neighbors are discarded due to the original early
return.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259691 91177308-0d34-0410-b5e6-96231b3b80d8
When generating calls to memcpy, memmove, and memset, use void* as the return
type rather than void, to match the standard signatures for these functions.
This has no practical effect for most targets, since the return values of
these calls aren't being used anyway, and most calling conventions tolerate
this kind of mismatch. However, this change will help support future
optimizations to utilize the return value to avoid holding the argument
value live across a call.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258691 91177308-0d34-0410-b5e6-96231b3b80d8
This reapplies r258296 and r258366, and also fixes an existing bug in
SelectionDAG.cpp's isMemSrcFromString, neglecting to account for the
offset in a GlobalAddressSDNode, which is uncovered by those patches.
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This reverts r258296 and the follow up r258366. With this change, we
miscompiled the following program on Windows:
#include <string>
#include <iostream>
static const char kData[] = "asdf jkl;";
int main() {
std::string s(kData + 3, sizeof(kData) - 3);
std::cout << s << '\n';
}
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SelectionDAG previously missed opportunities to fold constants into
GlobalAddresses in several areas. For example, given `(add (add GA, c1), y)`, it
would often reassociate to `(add (add GA, y), c1)`, missing the opportunity to
create `(add GA+c, y)`. This isn't often visible on targets such as X86 which
effectively reassociate adds in their complex address-mode folding logic,
however it is currently visible on WebAssembly since it currently has very
simple address mode folding code that doesn't reassociate anything.
This patch fixes this by making SelectionDAG fold offsets into GlobalAddresses
at the same times that it folds constants together, so that it doesn't miss any
opportunities to perform such folding.
Differential Revision: http://reviews.llvm.org/D16090
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In the optimizer (GVN etc.) when eliminating redundant nodes with different
flags, the flags are ignored for the purposes of testing for congruence, and
then intersected for the purposes of producing a result that supports the union
of all the uses. This commit makes SelectionDAG's CSE do the same thing,
allowing it to CSE nodes in more cases. This fixes PR26063.
Differential Revision: http://reviews.llvm.org/D15957
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Pulled out the similar CONCAT_VECTORS creation code from the 2/3 operand getNode() calls (to handle all UNDEF and all BUILD_VECTOR cases). Added a similar handler to the general getNode() call as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256709 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Previously SelectionDAGBuilder asserted that the pointer operands of
memcpy / memset / memmove intrinsics are in address space < 256. This assert
implicitly assumed the X86 backend, where all address spaces < 256 are
equivalent to address space 0 from the code generator's point of view. On some
targets (R600 and NVPTX) several address spaces < 256 have a target-defined
meaning, so this assert made little sense for these targets.
This patch removes this wrong assertion and adds extra checks before lowering
these intrinsics to library calls. If a pointer operand can't be casted to
address space 0 without changing semantics, a fatal error is reported to the
user.
The new behavior should be valid for all targets that give address spaces != 0
a target-specified meaning (NVPTX, R600, X86). NVPTX lowers big or
variable-sized memory intrinsics before SelectionDAG construction. All other
memory intrinsics are inlined (the threshold is set very high for this target).
R600 doesn't support memcpy / memset / memmove library calls (previously the
illegal emission of a call to such library function triggered an error
somewhere in the code generator). X86 now emits inline loads and stores for
address spaces 256 and 257 up to the same threshold that is used for address
space 0 and reports a fatal error otherwise.
I call this a "partial fix" because there are still cases that can't be
lowered. A fatal error is reported in these cases.
Reviewers: arsenm, theraven, compnerd, hfinkel
Subscribers: hfinkel, llvm-commits, alex
Differential Revision: http://reviews.llvm.org/D7241
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255441 91177308-0d34-0410-b5e6-96231b3b80d8
PR25763 demonstrated an issue with D14683 - vector comparison constant folding only works for i1 results, so we need to split off the sign-extension of the result to the required type. Luckily this can be done with the existing type legalization code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255289 91177308-0d34-0410-b5e6-96231b3b80d8
Almost all these changes are conditioned and only apply to the new
x86-64 f128 type configuration, which will be enabled in a follow up
patch. They are required together to make new f128 work. If there is
any error, we should fix or revert them as a whole.
These changes should have no impact to current configurations.
* Relax type legalization checks to accept new f128 type configuration,
whose TypeAction is TypeSoftenFloat, not TypeLegal, but also has
TLI.isTypeLegal true.
* Relax GetSoftenedFloat to return in some cases f128 type SDValue,
which is TLI.isTypeLegal but not "softened" to i128 node.
* Allow customized FABS, FNEG, FCOPYSIGN on new f128 type configuration,
to generate optimized bitwise operators for libm functions.
* Enhance related Lower* functions to handle f128 type.
* Enhance DAGTypeLegalizer::run, SoftenFloatResult, and related functions
to keep new f128 type in register, and convert f128 operators to library calls.
* Fix Combiner, Emitter, Legalizer routines that did not handle f128 type.
* Add ExpandConstant to handle i128 constants, ExpandNode
to handle ISD::Constant node.
* Add one more parameter to getCommonSubClass and firstCommonClass,
to guarantee that returned common sub class will contain the specified
simple value type.
This extra parameter is used by EmitCopyFromReg in InstrEmitter.cpp.
* Fix infinite loop in getTypeLegalizationCost when f128 is the value type.
* Fix printOperand to handle null operand.
* Enhance ISD::BITCAST node to handle f128 constant.
* Expand new f128 type for BR_CC, SELECT_CC, SELECT, SETCC nodes.
* Enhance X86AsmPrinter to emit f128 values in comments.
Differential Revision: http://reviews.llvm.org/D15134
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Summary:
Many target lowerings copy-paste the code to test SDValues for known constants.
This code can instead be shared in SelectionDAG.cpp, and reused in the targets.
Reviewers: MatzeB, andreadb, tstellarAMD
Subscribers: arsenm, jyknight, llvm-commits
Differential Revision: http://reviews.llvm.org/D14945
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This patch adds support for vector constant folding of integer/float comparisons.
This requires FoldConstantVectorArithmetic to support scalar constant operands (in this case ISD::CONDCASE). In future we should be able to support other scalar constant types as necessary (and possibly start calling FoldConstantVectorArithmetic for all node creations)
Differential Revision: http://reviews.llvm.org/D14683
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253504 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Don't call `computeKnownBitsFromRangeMetadata` for extended loads --
this can cause a mismatch between the width of the !range metadata and
the width of the APInt's accumulating `KnownZero` (and `KnownOne` in the
future). This isn't a problem now, but will be after a future change.
Note: this can be made more aggressive in the future.
Reviewers: nlewycky
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D14107
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While technically this is untested dead code, it has out-of-tree users.
This reverts a part of r250434.
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We have a number of functions that implement constant folding of vectors (unary and binary ops) in near identical manners (and the differences don't appear to be critical).
This patch introduces a common implementation (SelectionDAG::FoldConstantVectorArithmetic) and calls this in both the unary and binary op cases.
After this initial patch I intend to begin enabling vector constant folding for a wider number of opcodes in SelectionDAG::getNode().
Differential Revision: http://reviews.llvm.org/D13665
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visitSIGN_EXTEND_INREG calls SelectionDAG::getNode to constant fold scalar constants but handles vector constants itself, despite getNode being capable of dealing with them.
This required a minor change to the getNode implementation to actually deal with cases where the scalars of a BUILD_VECTOR were wider integers than the vector type - which was the only extra ability of the visitSIGN_EXTEND_INREG implementation.
No codegen intended and all existing tests remain the same.
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Because mod is always exact, this function should have never taken a rounding mode argument. The actual implementation still has issues, which I'll look at resolving in a subsequent patch.
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After D10403, we had FMF in the DAG but disabled by default. Nick reported no crashing errors after some stress testing,
so I enabled them at r243687. However, Escha soon notified us of a bug not covered by any in-tree regression tests:
if we don't propagate the flags, we may fail to CSE DAG nodes because differing FMF causes them to not match. There is
one test case in this patch to prove that point.
This patch hopes to fix or leave a 'TODO' for all of the in-tree places where we create nodes that are FMF-capable. I
did this by putting an assert in SelectionDAG.getNode() to find any FMF-capable node that was being created without FMF
( D11807 ). I then ran all regression tests and test-suite and confirmed that everything passes.
This patch exposes remaining work to get DAG FMF to be fully functional: (1) add the flags to non-binary nodes such as
FCMP, FMA and FNEG; (2) add the flags to intrinsics; (3) use the flags as conditions for transforms rather than the
current global settings.
Differential Revision: http://reviews.llvm.org/D12095
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In searching for a fix for the underlying code-quality bug highlighted by
r246937 (that SDAG simplification can lead to us generating an ISD::OR node
with a constant zero LHS), I ran across this:
We generically canonicalize commutative binary-operation nodes in SDAG getNode
so that, if only one operand is a constant, it will be on the RHS. However, we
were doing this only after a bunch of constant-based simplification checks that
all assume this canonical form (that any constant will be on the RHS). Moving
the operand-swapping canonicalization prior to these checks seems like the
right thing to do (and, as it turns out, causes SDAG to completely fold away the
computation in test/CodeGen/ARM/2012-11-14-subs_carry.ll, just like InstCombine
would do).
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