It's still possible that there's a simpler way to specify
the conditions needed for this set of folds, but "getStrictPred"
converts >= to > for example, so there's no need to explicitly
check that.
This extends e5d15e116292 to handle the inverse predicates
(there's probably a more elegant way to specify the preds).
These patterns correspond to the existing simplify:
max (min X, Y), X --> X
...and extra preds for (non)equality.
The tests cycle through all 10 icmp preds for each min/max
variant with 4 swapped operand patterns each (and the min/max
operands are commuted in every other test within those).
Some Alive2 examples to verify:
https://alive2.llvm.org/ce/z/XMvEKQhttps://alive2.llvm.org/ce/z/QpMChr
This is similar to the existing simplify:
max (max X, Y), X --> max X, Y
...but the select condition can be one of
several predicates as shown in the tests.
The tests cycle through all 10 icmp preds for
each min/max variant with 4 swapped operand
patterns each (and the min/max operands are
commuted in every other test within those).
Some Alive2 examples to verify:
https://alive2.llvm.org/ce/z/lCAQm4https://alive2.llvm.org/ce/z/kzxVXC
We can handle vectors inside simplifyWithOpReplaced(), as long as
cross-lane operations are excluded. The equality can hold (or not
hold) for each vector lane independently, so we shouldn't use the
replacement value from other lanes.
I believe the only operations relevant here are shufflevector (where
all previous bugs were seen) and calls (which might use shuffle-like
intrinsics and would require more careful classification).
Differential Revision: https://reviews.llvm.org/D134348
We already support SGE, so the same logic should hold for SLE with
the LHS and RHS swapped.
I didn't see this in the wild. Just happened to walk past this code
and thought it was odd that it was asymmetric in what condition
codes it handled.
Reviewed By: spatel, reames
Differential Revision: https://reviews.llvm.org/D131805
My most recent change for D131607 had a formatting error that I didn't
notice until after I committed it. Let me fix it now so changes to this
file will be back-to-back from me.
Another ticket split out of D107285, this extends the optimization
of 0.0 - -X to just X when using constrained intrinsics and the
optimization is allowed.
If the negation of X is done with fsub then the match fails because of
the lack of IR Matcher support for constrained intrinsics.
While I'm here, remove some TODO notices since the work is no longer
planned.
Differential Revision: https://reviews.llvm.org/D131607
As suggested in the post-commit comments for 019d76196f79fcff3c148,
this makes the usage symmetric with the 'and' patterns and should
be more efficient.
We get a couple of improvements from recognizing swapped
operand patterns that were not handled by the replicated
code.
This should also enable simplifying larger patterns as
seen in issue #56653 and issue #56654, but that requires
enhancements to isImpliedCondition() itself.
issue #56775
I rearranged the Thumb2 codegen test to avoid simplifying the chain
of rounding instructions. I'm assuming the intent of the test is
to verify lowering of each of those intrinsics.
We already call the more general isImpliedCondition() (which calls
isImpliedTrueByMatchingCmp() internally) from simplifyAndInst()
and simplifyOrInst().
There was a difference visible with this change on a vector test
before a925bef70c6c, but I can't find any gaps now.
As integer div/rem constant expressions are no longer supported,
constants can no longer trap and are always safe to speculate.
Remove the Constant::canTrap() method and its usages.
Handle denormal constant input for fcmp instructions based on the
denormal handling mode.
Reviewed By: spatel, dcandler
Differential Revision: https://reviews.llvm.org/D128647
This allows all constant folding to happen through a single
function, without requiring special handling for loads at each
call-site.
This may not be NFC because some callers currently don't do that
special handling.
Support compares in ConstantFoldInstOperands(), instead of
forcing the use of ConstantFoldCompareInstOperands(). Also handle
insertvalue (extractvalue was already handled).
This removes a footgun, where many uses of ConstantFoldInstOperands()
need a separate check for compares beforehand. It's particularly
insidious if called on a constant expression, because it doesn't
fail in that case, but will just not do DL-dependent folding.
These intrinsics are now fundemental for SVE code generation and have been
present for a year and a half, hence move them out of the experimental
namespace.
Differential Revision: https://reviews.llvm.org/D127976
Depending on the environment, a floating point instruction should
treat denormal inputs as zero, and/or flush a denormal output to zero.
Denormals are not currently accounted for when an instruction gets
folded to a constant, which can lead to differences in output between
a folded and a unfolded instruction when running on the target. The
denormal handling mode can be set by the function level attribute
denormal-fp-math, which this patch uses to determine whether any
denormal inputs to or outputs from folding should be zero, and that
the sign is set appropriately.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D116952
Unfortunately, it's not just constant expressions that can trap,
we might also have a trapping constant expression nested inside
a constant aggregate.
Perform the check during phi folding on Constant rather than
ConstantExpr, and extend the Constant::mayTrap() implementation
to also recursive into ConstantAggregates, not just ConstantExprs.
Fixes https://github.com/llvm/llvm-project/issues/49839.
Clang-format InstructionSimplify and convert all "FunctionName"s to
"functionName". This patch does touch a lot of files but gets done with
the cleanup of InstructionSimplify in one commit.
This is the alternative to the less invasive clang-format only patch: D126783
Reviewed By: spatel, rengolin
Differential Revision: https://reviews.llvm.org/D126889
This adds two conjugated folds:
* A | B -> B if A implies B (https://alive2.llvm.org/ce/z/R6GU4j)
* A & B -> A if A implies B (https://alive2.llvm.org/ce/z/EGMqyy)
If A and B are icmps themselves, we will usually fold this through
other logic already (though the tests show a couple additional cases
we previously missed). However, isImpliedCond() also supports A
being of the form X & Y, which allows us to handle cases like
(X & Y) | B where X implies B. This addresses the regression from
D125398.
Something that notably doesn't work yet is the (X | Y) & B case.
This is due to an asymmetry in the isImpliedCondition()
implementation that will have to be addressed separately.
Differential Revision: https://reviews.llvm.org/D125530
This issue reproduces in the context of LoopDeletion, because the
bitcast does not get simplified away there. For a plain -inst-simplify
run the bitcast would get folded away first.
Fixes https://github.com/llvm/llvm-project/issues/54615.
If a constrained intrinsic call was replaced by some value, it was not
removed in some cases. The dangling instruction resulted in useless
instructions executed in runtime. It happened because constrained
intrinsics usually have side effect, it is used to model the interaction
with floating-point environment. In some cases side effect is actually
absent or can be ignored.
This change adds specific treatment of constrained intrinsics so that
their side effect can be removed if it actually absents.
Differential Revision: https://reviews.llvm.org/D118426
Currently the fsub optimizations in InstSimplify don't know how to fold
-0.0 - (-X) to X when the constrained intrinsics are used. This adds partial
support. The rest of the support will come later with work on the IR
matchers.
This review is split out from D107285.
Differential Revision: https://reviews.llvm.org/D123396
In D111530, I suggested that we add some relatively basic pattern-matching
folds for shifts and funnel shifts and avoid a more specialized solution
if possible.
We can start by implementing at least one of these in IR because it's
easier to write the code and verify with Alive2:
https://alive2.llvm.org/ce/z/qHpmNn
This will need to be adapted/extended for SDAG to handle the motivating
bug ( #49541 ) because the patterns only appear later with that example
(added some tests: bb850d422b64)
This can be extended within InstSimplify to handle cases where we 'and'
with a shift too (in that case, kill the funnel shift).
We could also handle patterns where the shift and funnel shift directions
are inverted, but I think it's better to canonicalize that instead to
avoid pattern-match case explosion.
Differential Revision: https://reviews.llvm.org/D120253
The code was using exact sizing only, but since what we really need is just to make sure the offsets are in bounds, a minimum bound on the object size is sufficient.
To demonstrate the difference, support computing minimum sizes from obects of scalable vector type.
Remove some code which tried to handle the case of comparing two allocas where an object size could not be precisely computed. This code had zero coverage in tree, and at least one nasty bug.
The bug comes from the fact that the code uses the size of the result pointer as a proxy for whether the alloca can be of size zero. Since the result of an alloca is *always* a pointer type, and a pointer type can *never* be empty, this check was a nop. As a result, we blindly consider a zero offset from two allocas to never be equal. They can in fact be equal when one or more of the allocas is zero sized.
This is particularly ugly because instcombine contains the exact opposite rule. If instcombine reaches the allocas first, it combines them into one (making them equal). If instsimplify reaches the compare first, it would consider them not equal. This creates all kinds of fun scenarios for order of optimization reaching different and contradictory conclusions.
