As per the stack of patches this is attached to, allow users of
BasicBlock::splitBasicBlock to provide an iterator for a position, instead
of just an instruction pointer. This is to fit with my proposal for how to
get rid of debug intrinsics [0]. There are other call-sites that would need
to change, but this is sufficient for a stage2clang self host and some
other C++ projects to build identical binaries, in the context of the whole
remove-DIs project.
[0] https://discourse.llvm.org/t/rfc-instruction-api-changes-needed-to-eliminate-debug-intrinsics-from-ir/68939
Differential Revision: https://reviews.llvm.org/D152545
Continuing the patch series to get rid of debug intrinsics [0], instruction
insertion needs to be done with iterators rather than instruction pointers,
so that we can communicate information in the iterator class. This patch
adds an iterator-taking insertBefore method and converts various call sites
to take iterators. These are all sites where such debug-info needs to be
preserved so that a stage2 clang can be built identically; it's likely that
many more will need to be changed in the future.
At this stage, this is just changing the spelling of a few operations,
which will eventually become signifiant once the debug-info bearing
iterator is used.
[0] https://discourse.llvm.org/t/rfc-instruction-api-changes-needed-to-eliminate-debug-intrinsics-from-ir/68939
Differential Revision: https://reviews.llvm.org/D152537
As outlined in my proposal of how to get rid of debug intrinsics, this
patch adds a moveBefore method that signals the caller /intends/ the order
of moved instructions is to stay the same. This semantic difference has an
effect on debug-info, as it signals whether debug-info needs to move with
instructions or not.
The patch just replaces a few calls to moveBefore with calls to
moveBeforePreserving -- and the latter just calls the former, so it's all
NFC right now. A future patch will add an implementation of
moveBeforePreserving that takes action to correctly preserve debug-info,
but that's tightly coupled with our non-instruction debug-info
representation that's still being reviewed.
[0] https://discourse.llvm.org/t/rfc-instruction-api-changes-needed-to-eliminate-debug-intrinsics-from-ir/68939
Differential Revision: https://reviews.llvm.org/D156369
isLegalToHoistInto() currently return true for callbr instructions.
That means that a callbr with one successor will be considered a
proper loop preheader, which may result in instructions that use
the callbr return value being hoisted past it.
Fix this by adding callbr to isExceptionTerminator (with a rename
to isSpecialTerminator), which also fixes similar assumptions in
other places.
Fixes https://github.com/llvm/llvm-project/issues/64215.
Differential Revision: https://reviews.llvm.org/D158609
This is the next preparation patch to support widenable conditions
widening instead of branches widening.
We've added parseWidenableGuard util which parses guard condition and
collects all checks existing in the expression tree: D157276
Here we are adding util which walks similar way through the expression
tree but looks up for widenable condition without collecting the checks.
Therefore llvm::extractWidenableCondition could parse widenable branches
with arbitrary position of widenable condition in the expression tree.
llvm::parseWidenableBranch which is we are going to get rid of is being
replaced by llvm::extractWidenableCondition where it's possible.
Reviewed By: anna
Differential Revision: https://reviews.llvm.org/D157529
swifterror pointers can only be used as pointer operands of load & store
instructions (and as swifterror argument of a call). Sinking loads or
stores with swifterror pointer operands would require introducing a
select of of the pointer operands, which isn't allowed.
Check for this condition in canSinkInstructions.
Reviewed By: aschwaighofer
Differential Revision: https://reviews.llvm.org/D158083
Add an API that allows removing multiple incoming phi values based
on a predicate callback, as suggested on D157621.
This makes sure that the removal is linear time rather than quadratic,
and avoids subtleties around iterator invalidation.
I have replaced some of the more straightforward users with the new
API, though there's a couple more places that should be able to use it.
Differential Revision: https://reviews.llvm.org/D158064
Guard FoldBranchToCommonDest in SimplifyCFG with the SpeculateBlocks
flag as it can also speculate instructions.
This was split out of D155997.
Differential Revision: https://reviews.llvm.org/D156194
When new assumption is created it should be registered in assumption cache
or cache should be invalidated.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D154601
This reverts commit 20f0c68fd83a0147a8ec1722bd2e848180610288.
https://reviews.llvm.org/D153966#4464594 reports an optimization
regression in Rust.
Additionally this change has caused an unexpected 0.3% compile-time
regression.
This reverts commit 0c03f48480f69b854f86d31235425b5cb71ac921.
Going to fix forward size regression instead due to more dependent patches needing to be reverted otherwise.
Instead of setting the SimplifyCFGOptions options at the beginning of the pass.
Otherwise it always gets overriden by the pass and the value in SimplifyCFGOptions is ignored.
Unlike every other analysis and transform, simplifyInstruction
permitted operating on instructions which are not inserted
into a function. This created an edge case no other code needs
to really worry about, and limited transforms in cases that
can make use of the context function. Only the inliner and a handful
of other utilities were making use of this, so just fix up these
edge cases. Results in some IR ordering differences since
cloned blocks are inserted eagerly now. Plus some additional
simplifications trigger (e.g. some add 0s now folded out that
previously didn't).
This commit removes constness from DILocation::getMergedLocation and
fixes all its users accordingly.
Having constness on the parameters forced the return type to be const
as well, which does force usage of `const_cast` when the location needs
to be used in metadata nodes.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D149942
D129370 introduced the idea that hoisting could skip over non-matching
instructions and continue to look for matching (hoistable) instructions,
but certain types of mismatch still aborted the whole hoisting attempt.
Fix this by splitting out some of the instruction matching checks into a
helper function.
Also forbid hoisting allocas past stacksave/stackrestore, completing the
fix started in D133730, to avoid regressing tests.
Differential Revision: https://reviews.llvm.org/D149365
This exposed another miscompile in GVN, which was fixed by
20e9b31f88149a1d5ef78c0be50051e345098e41.
-----
After D141386, violation of nonnull, range and align metadata
results in poison rather than immediate undefined behavior,
which means that these are now safe to retain when speculating.
We only need to remove UB-implying metadata like noundef.
This is done by adding a dropUBImplyingAttrsAndMetadata() helper,
which lists the metadata which is known safe to retain on speculation.
Differential Revision: https://reviews.llvm.org/D146629
This exposed a miscompile in GVN, which was fixed by D148129.
-----
After D141386, violation of nonnull, range and align metadata
results in poison rather than immediate undefined behavior,
which means that these are now safe to retain when speculating.
We only need to remove UB-implying metadata like noundef.
This is done by adding a dropUBImplyingAttrsAndMetadata() helper,
which lists the metadata which is known safe to retain on speculation.
Differential Revision: https://reviews.llvm.org/D146629
After D141386, violation of nonnull, range and align metadata
results in poison rather than immediate undefined behavior,
which means that these are now safe to retain when speculating.
We only need to remove UB-implying metadata like noundef.
This is done by adding a dropUBImplyingAttrsAndMetadata() helper,
which lists the metadata which is known safe to retain on speculation.
Differential Revision: https://reviews.llvm.org/D146629
Don't merge invokes if this replaces constant operands with phis
in a place where this is not legal.
This also disallows converting operand bundles from constant to
non-constant, in line with the restriction we use in other
transforms.
Fixes https://github.com/llvm/llvm-project/issues/61265.
Differential Revision: https://reviews.llvm.org/D146723
Currently SimplifyCFG hoists/sink common instructions in then/else basic blocks
when certain options are enabled, which is the case for default clang optimization
pipelines for -O3. It tries to hoist/sink convergent function calls in divergent
control flow, which causes incorrect ISA generated for GPU, e.g.
https://github.com/ROCm-Developer-Tools/HIP/issues/3172
This patch fixes that by conservatively disable hoisting/sinking common
convergent function calls in then/else blocks.
Reviewed by: Artem Belevich
Differential Revision: https://reviews.llvm.org/D144756
The result value of `getelementptr inbounds (TY, null, not zero)` is a poison value. We can think of it as undefined behavior.
> Please let me know if there is anything I don't understand correctly.
Reviewed By: nikic, xbolva00
Differential Revision: https://reviews.llvm.org/D144563
