Fixes#76623
Alive2 proof: https://alive2.llvm.org/ce/z/gX6znJ (I'm not sure how to
write a proof for such transform, maybe there are mistakes)
In most cases, `icmp(a, C1) && (other_cond && icmp(a, C2))` will be
reduced to `icmp(a, C1) & (other_cond && icmp(a, C2))`, since latter
icmp always implies the poison of the former. After reduction, it's
easier to simplify the icmp chain.
Similarly, this patch does the same thing for `(A && B) && C --> A && (B
& C)`. Maybe we could constraint such reduction only on icmps if there
is regression in benchmarks.
`and/or/xor` operations can each be changed to sum of logical
operations including operators other than themselves.
`x&y -> (x|y) ^ (x^y)`
`x|y -> (x&y) | (x^y)`
`x^y -> (x|y) ^ (x&y)`
if left of condition of `SelectInst` is `and/or/xor` logical
operation and right is equal to `0, -1`, or a `constant`, and
if `TrueVal` consist of `and/or/xor` logical operation then we
can optimize this case.
This patch implements this combination.
Proof: https://alive2.llvm.org/ce/z/WW8iRR
Fixes https://github.com/llvm/llvm-project/issues/71792.
Folding a select-like `shufflevector` into a floating point binary
operators can only be done if the result is preserved for both case. In
particular, if the common operand of the `shufflevector` and the
floating point binary operator can be a NaN, then the transformation
won't preserve the result value.
This reverts commit d80d5b923c6f611590a12543bdb33e0c16044d44.
It wasn't a particularly important transform to begin with and caused
some codegen regressions on targets that prefer `sitofp` so dropping.
Might re-visit along with adding `nneg` flag to `uitofp` so its easily
reversable for the backend.
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.
Folding a `select` into a floating point binary operators can only be
done if the result is preserved for both case. In particular, if the
other operand of the `select` can be a NaN, then the transformation
won't preserve the result value.
This patch enables more optimization after canonicalizing `fmul X, 0.0`
into a copysign.
I decide to implement this fold in InstCombine because
`computeKnownFPClass` may be expensive.
Alive2: https://alive2.llvm.org/ce/z/ASM8tQ
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
Try to transform the powi(X, Y) * X into powi(X, Y+1) with Ofast
For this case, when the Y is 3, then powi(X, 4) is replaced by
X2 = X * X; X2 * X2 in the further step.
Similar to D109954, who requires reassoc.
Fixes https://github.com/llvm/llvm-project/issues/69862.
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.
This patch fixes the issues introduced in
bb5c3899d1.
I moved the check for the instruction to be div before I check for the
fast math flags which resolves the crash in
```
float a, b;
double sqrt();
void c() { b = a / sqrt(a); }
```
---------
Co-authored-by: Matt Arsenault <arsenm2@gmail.com>
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
Targets the dynamic realignment pattern of `(Ptr + Align - 1) & -Align;`
as implemented by gep then ptrmask.
Specifically, when the pointer already has alignment information,
dynamically realigning it to less than is already known should be a
no-op. Discovered while writing test cases for another patch.
For the zero low bits of a known aligned pointer, adding the gep index
then removing it with a mask is a no-op. Folding the ptrmask effect
entirely into the gep is the ideal result as that unblocks other
optimisations that are not aware of ptrmask.
In some other cases the gep is known to be dead and is removed without
changing the ptrmask.
In the least effective case, this transform creates a new gep with a
rounded-down index and still leaves the ptrmask unchanged. That
simplified gep is still a minor improvement, geps are cheap and ptrmask
occurs in address calculation contexts so I don't think it's worth
special casing to avoid the extra instruction.
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.
When replacing with a non-constant, it's possible that the result of the
simplification is actually more complicated than the original, and may
result in an infinite combine loop.
Mitigate the issue by requiring that either the replacement or
simplification result is constant, which should ensure that it's
simpler. While this check is crude, it does not appear to cause
optimization regressions in real-world code in practice.
Fixes https://github.com/llvm/llvm-project/issues/83127.
As part of the RemoveDIs project we need LLVM to insert instructions using
iterators wherever possible, so that the iterators can carry a bit of
debug-info. This commit implements some of that by updating the contents of
llvm/lib/Transforms/Utils to always use iterator-versions of instruction
constructors.
There are two general flavours of update:
* Almost all call-sites just call getIterator on an instruction
* Several make use of an existing iterator (scenarios where the code is
actually significant for debug-info)
The underlying logic is that any call to getFirstInsertionPt or similar
APIs that identify the start of a block need to have that iterator passed
directly to the insertion function, without being converted to a bare
Instruction pointer along the way.
Noteworthy changes:
* FindInsertedValue now takes an optional iterator rather than an
instruction pointer, as we need to always insert with iterators,
* I've added a few iterator-taking versions of some value-tracking and
DomTree methods -- they just unwrap the iterator. These are purely
convenience methods to avoid extra syntax in some passes.
* A few calls to getNextNode become std::next instead (to keep in the
theme of using iterators for positions),
* SeparateConstOffsetFromGEP has it's insertion-position field changed.
Noteworthy because it's not a purely localised spelling change.
All this should be NFC.
