Use ICmpInst::compare() where possible, ConstantFoldCompareInstOperands
in other places. This only changes places where the either the fold is
guaranteed to succeed, or the code doesn't use the resulting compare if
we fail to fold.
Canonicalize getelementptr instructions for scalable vector types into
ptradd representation with an explicit llvm.vscale call. This
representation has better support in BasicAA, which can reason about
llvm.vscale, but not plain scalable GEPs.
This patch is moving out following intrinsics:
* vector.interleave2/deinterleave2
* vector.reverse
* vector.splice
from the experimental namespace.
All these intrinsics exist in LLVM for more than a year now, and are
widely used, so should not be considered as experimental.
When canonicalizing gep+add into gep+gep we can preserve inbounds if the
add is also nsw and both add operands are non-negative (or both
negative, but I don't think that's practically relevant).
Proof: https://alive2.llvm.org/ce/z/tJLBta
This change adds the z/OS personality function to the list of known EH
personality functions. It enables removing of the EH data/labels if the
personality function is not invoked.
In #88217 a large set of matchers was changed to only accept poison
values in splats, but not undef values. This is because we now use
poison for non-demanded vector elements, and allowing undef can cause
correctness issues.
This patch covers the remaining matchers by changing the AllowUndef
parameter of getSplatValue() to AllowPoison instead. We also carry out
corresponding renames in matchers.
As a followup, we may want to change the default for things like m_APInt
to m_APIntAllowPoison (as this is much less risky when only allowing
poison), but this change doesn't do that.
There is one caveat here: We have a single place
(X86FixupVectorConstants) which does require handling of vector splats
with undefs. This is because this works on backend constant pool
entries, which currently still use undef instead of poison for
non-demanded elements (because SDAG as a whole does not have an explicit
poison representation). As it's just the single use, I've open-coded a
getSplatValueAllowUndef() helper there, to discourage use in any other
places.
Rename has/dropPoisonGeneratingFlagsOrMetadata to
has/dropPoisonGeneratingAnnotations and make it also handle
nonnull, align and range return attributes on calls, similar
to the existing handling for !nonnull, !align and !range metadata.
Prior to #85863, the required parameters of llvm::isKnownNonZero were
Value and DataLayout. After, they are Value, Depth, and SimplifyQuery,
where SimplifyQuery is implicitly constructible from DataLayout. The
change to move Depth before SimplifyQuery needed callers to be updated
unnecessarily, and as commented in #85863, we actually want Depth to be
after SimplifyQuery anyway so that it can be defaulted and the caller
does not need to specify it.
An example from https://github.com/image-rs/image:
```
define void @test_ult_rhsc(i8 %x) {
%val = add nsw i8 %x, -2
%cmp = icmp ult i8 %val, 11
%cond = select i1 %cmp, i8 %val, i8 6
switch i8 %cond, label %bb1 [
i8 0, label %bb2
i8 10, label %bb3
]
bb1:
call void @func1()
unreachable
bb2:
call void @func2()
unreachable
bb3:
call void @func3()
unreachable
}
```
When `%cmp` evaluates to false, we can prove that the range of `%val` is
[11, umax]. Thus we can safely replace `%cond` with `%val` since both
`switch 6` and `switch %val` go to the default dest `%bb1`.
Alive2: https://alive2.llvm.org/ce/z/uSTj6w
Godbolt: https://godbolt.org/z/MGrG84bzr
This patch will benefit many rust applications and some C/C++
applications (e.g., cvc5).
This is the major rename patch that prior patches have built towards.
The DPValue class is being renamed to DbgVariableRecord, which reflects
the updated terminology for the "final" implementation of the RemoveDI
feature. This is a pure string substitution + clang-format patch. The
only manual component of this patch was determining where to perform
these string substitutions: `DPValue` and `DPV` are almost exclusively
used for DbgRecords, *except* for:
- llvm/lib/target, where 'DP' is used to mean double-precision, and so
appears as part of .td files and in variable names. NB: There is a
single existing use of `DPValue` here that refers to debug info, which
I've manually updated.
- llvm/tools/gold, where 'LDPV' is used as a prefix for symbol
visibility enums.
Outside of these places, I've applied several basic string
substitutions, with the intent that they only affect DbgRecord-related
identifiers; I've checked them as I went through to verify this, with
reasonable confidence that there are no unintended changes that slipped
through the cracks. The substitutions applied are all case-sensitive,
and are applied in the order shown:
```
DPValue -> DbgVariableRecord
DPVal -> DbgVarRec
DPV -> DVR
```
Following the previous rename patches, it should be the case that there
are no instances of any of these strings that are meant to refer to the
general case of DbgRecords, or anything other than the DPValue class.
The idea behind this patch is therefore that pure string substitution is
correct in all cases as long as these assumptions hold.
When speculating an instruction in `InstCombinerImpl::FoldOpIntoSelect`,
the call may result in undefined behavior. This patch drops all
UB-implying attrs/metadata to fix this.
Fixes#85536.
This patch adds the support for and/or in `getFreelyInvertedImpl` using
DeMorgan's Law:
```
(~(A | B)) -> (~A & ~B)
(~(A & B)) -> (~A | ~B)
```
Alive2: https://alive2.llvm.org/ce/z/Uig8-j
This patch changes DPValue::filter to be a non-member method
filterDbgVars. There are two reasons for this: firstly, the name of
DPValue is about to change to DbgVariableRecord, which will result in
every `for` loop that uses DPValue::filter to require a line break. This
is a small thing, but it makes the rename patch more difficult to
review, and is just generally more awkward for what is a fairly common
loop. Secondly, the intent is to later break up the DPValue class into
subclasses, at which point it would be better to have a non-member
function that allows template arguments for the cases we want to filter
with greater specificity.
This patch canonicalizes `extractvalue (select Cond, TV, FV)` into
`select Cond, (extractvalue TV), (extractvalue FV)`. The latter form may
enable more optimizations.
As part of the effort to rename the DbgRecord classes, this patch
renames the widely-used functions that operate on DbgRecords but refer
to DbgValues or DPValues in their names to refer to DbgRecords instead;
all such functions are defined in one of `BasicBlock.h`,
`Instruction.h`, and `DebugProgramInstruction.h`.
This patch explicitly does not change the names of any comments or
variables, except for where they use the exact name of one of the
renamed functions. The reason for this is reviewability; this patch can
be trivially examined to determine that the only changes are direct
string substitutions and any results from clang-format responding to the
changed line lengths. Future patches will cover renaming variables and
comments, and then renaming the classes themselves.
Instead of taking the sign of the cast operation as the required since
for the transform, only force a sign if an operation is maybe
negative.
This gives us more flexability when checking if the floats are safely
converable to integers.
Closes#84389
The full fold is one of the following:
1) `(fp_binop ({s|u}itofp x), ({s|u}itofp y))`
-> `({s|u}itofp (int_binop x, y))`
2) `(fp_binop ({s|u}itofp x), FpC)`
-> `({s|u}itofp (int_binop x, (fpto{s|u}i FpC)))`
And support the following binops:
`fmul` -> `mul`
`fadd` -> `add`
`fsub` -> `sub`
Proofs: https://alive2.llvm.org/ce/z/zuacA8
The proofs timeout, so they must be reproduced locally.
Closes#82555
Instructions in unreachable basic blocks are removed, but terminators
are not. In this case, even instructions that are only referenced by
a terminator, such as a return instruction, cannot be processed
properly.
This patch changes the operand of a return instruction in an
unreachable basic block to poison if it refers to the instruction,
allowing the instruction to be properly processed.
Fixes#65107.
Patch 1 of 3 to add llvm.dbg.label support to the RemoveDIs project. The
patch stack adds a new base class
-> 1. Add DbgRecord base class for DPValue and the not-yet-added
DPLabel class.
2. Add the DPLabel class.
3. Enable dbg.label conversion and add support to passes.
Patches 1 and 2 are NFC.
In the near future we also will rename DPValue to DbgVariableRecord and
DPLabel to DbgLabelRecord, at which point we'll overhaul the function
names too. The name DPLabel keeps things consistent for now.
This reverts commit ef388334ee5a3584255b9ef5b3fefdb244fa3fd7.
The referenced issue violates the spec for finite-only math only by
using a return value for a constant infinity. If the interpretation
is results and arguments cannot violate nofpclass, then any
std::numeric_limits<T>::infinity() result is invalid under
-ffinite-math-only. Without this interpretation the utility of
nofpclass is slashed.
This patch does the following folds if only the overflow result is used:
```
extractvalue (umul.with.overflow iN X, X), 1 -> icmp ugt X, 2^(N/2)-1
```
Alive2: https://alive2.llvm.org/ce/z/a8yPC6
In instcombine, when we sink an instruction into a successor block, we try
to clone and salvage all the variable assignments that use that Value. This
is a behaviour that's (IMO) flawed, but there are important use cases where
we want to avoid regressions, thus we're implementing this for the
non-instruction debug-info representation.
This patch refactors the dbg.value sinking code into it's own function, and
installs a parallel implementation for DPValues, the non-instruction
debug-info container. This is mostly identical to the dbg.value
implementation, except that we don't have an easy-to-access ordering
between DPValues, and have to jump through extra hoops to establish one in
the (rare) cases where that ordering is required.
The test added represents a common use-case in LLVM where these behaviours
are important: a loop has been completely optimised away, leaving several
dbg.values in a row referring to an instruction that's going to sink. The
dbg.values should sink in both dbg.value and RemoveDIs mode, and
additionally only the last assignment should sink.
This patch canonicalizes getelementptr instructions with constant
indices to use the `i8` source element type. This makes it easier for
optimizations to recognize that two GEPs are identical, because they
don't need to see past many different ways to express the same offset.
This is a first step towards
https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699.
This is limited to constant GEPs only for now, as they have a clear
canonical form, while we're not yet sure how exactly to deal with
variable indices.
The test llvm/test/Transforms/PhaseOrdering/switch_with_geps.ll gives
two representative examples of the kind of optimization improvement we
expect from this change. In the first test SimplifyCFG can now realize
that all switch branches are actually the same. In the second test it
can convert it into simple arithmetic. These are representative of
common optimization failures we see in Rust.
Fixes https://github.com/llvm/llvm-project/issues/69841.
With the soon-to-land new-debug-info storage model, it's going to be
important to use iterators for instruction insertion rather than
instruction pointers. This (single line in instcombine) is the last place
that trips up our internal testing for debug-info, where we insert a PHI
and it should be using an iterator.
`(ctpop (not x))` <-> `(sub nuw nsw BitWidth(x), (ctpop x))`. The
`sub` expression can sometimes be constant folded depending on the use
case of `(ctpop (not x))`.
This patch adds fold for the following cases:
`(add/sub/disjoint_or C, (ctpop (not x))`
-> `(add/sub/disjoint_or C', (ctpop x))`
`(cmp pred C, (ctpop (not x))`
-> `(cmp swapped_pred C', (ctpop x))`
Where `C'` depends on how we constant fold `C` with `BitWidth(x)` for
the given opcode.
Proofs: https://alive2.llvm.org/ce/z/qUgfF3Closes#77859
This patch folds `switch(zext/sext(X))` into `switch(X)`.
The original motivation of this patch is to optimize a pattern found in
cvc5. For example:
```
%bf.load.i = load i16, ptr %d_kind.i, align 8
%bf.clear.i = and i16 %bf.load.i, 1023
%bf.cast.i = zext nneg i16 %bf.clear.i to i32
switch i32 %bf.cast.i, label %if.else [
i32 335, label %if.then
i32 303, label %if.then
]
if.then: ; preds = %entry, %entry
%d_children.i.i = getelementptr inbounds %"class.cvc5::internal::expr::NodeValue", ptr %0, i64 0, i32 3
%cmp.i.i.i.i.i = icmp eq i16 %bf.clear.i, 1023
%cond.i.i.i.i.i = select i1 %cmp.i.i.i.i.i, i32 -1, i32 %bf.cast.i
```
`%cmp.i.i.i.i.i` always evaluates to false because `%bf.clear.i` can
only be 335 or 303.
Folding `switch i32 %bf.cast.i` to `switch i16 %bf.clear.i` will help
`CVP` to handle this case.
See also
https://github.com/llvm/llvm-project/pull/76928#issuecomment-1877055722.
Compile-time impact:
http://llvm-compile-time-tracker.com/compare.php?from=7954c57124b495fbdc73674d71f2e366e4afe522&to=502b13ed34e561d995ae1f724cf06d20008bd86f&stat=instructions:u
|stage1-O3|stage1-ReleaseThinLTO|stage1-ReleaseLTO-g|stage1-O0-g|stage2-O3|stage2-O0-g|stage2-clang|
|--|--|--|--|--|--|--|
|+0.03%|+0.06%|+0.07%|+0.00%|-0.02%|-0.03%|+0.02%|
This patch cleans up the duplicate code for folding commutative binops
over `select/phi/minmax`.
Related commits:
+ select support:
88cc35b27e
+ phi support:
8674a023bc
+ minmax support:
624973806c
7d7001b2cb
canonicalizes `(gep i8, X, (ptrtoint Y) - (ptrtoint X))` into `bitcast
Y` iff `X` and `Y` have the same underlying object.
I find that the result of this pattern is usually used as an operand of
an icmp in some real-world applications. I think we can do the
canonicalization if the result is only used by icmps/ptrtoints.
Alive2: https://alive2.llvm.org/ce/z/j4-HJZ
This patch canonicalize `gep T* X, V / sizeof(T)` to `gep i8* X, V`.
Alive2: https://alive2.llvm.org/ce/z/7XGjiB
As this pattern has been handled by the backends, the motivation of this
patch is to reduce the ref count of sdiv, which will enable more
optimizations.
In line with updated shufflevector semantics, this represents the
poison elements rather than undef elements now. This commit is a
pure rename, without any logic changes.
