llvm-project.git/llvm/test/Transforms/SimplifyCFG/annotations.ll, branch users/nico/python-2

[SimplifyCFG] Convert tests to opaque pointers (NFC)

2022-12-14T14:14:12+00:00

[NFC] Port all runlines for SimplifyCFG pass tests to -passes syntax

2022-12-05T18:12:20+00:00

Reland "[SimplifyCFG] Update FoldBranchToCommonDest to be poison-safe"

2021-03-23T00:19:53+00:00

This relands commit 99108c791de0285ee726a10e8274772b18cee73c (D95026) which was
reverted by 8d5a981a135a0f0ae0a10c59b7c8093aae1c28de because the underlying
problem (https://llvm.org/pr49495) is fixed.

Revert "[SimplifyCFG] Update FoldBranchToCommonDest to be poison-safe"

2021-03-08T00:15:47+00:00

This reverts commit 99108c791de0285ee726a10e8274772b18cee73c.
Clang is miscompiling LLVM with this change, a stage-2 build hits
multiple failures.

As a repro, I built clang in a stage1 directory and used it this way:

cmake -G Ninja ../llvm \
  -DCMAKE_CXX_COMPILER=`pwd`/../build-stage1/bin/clang++ \
  -DCMAKE_C_COMPILER=`pwd`/../build-stage1/bin/clang \
  -DLLVM_TARGETS_TO_BUILD="X86;NVPTX;AMDGPU" \
  -DLLVM_ENABLE_PROJECTS=mlir \
  -DLLVM_BUILD_EXAMPLES=ON \
  -DCMAKE_BUILD_TYPE=Release \
  -DLLVM_ENABLE_ASSERTIONS=On
ninja check-mlir

[SimplifyCFG] Update FoldBranchToCommonDest to be poison-safe

2021-03-07T16:38:03+00:00

This patch makes FoldBranchToCommonDest merge branch conditions into `select i1` rather than `and/or i1` when it is called by SimplifyCFG.
It is known that merging conditions into and/or is poison-unsafe, and this is towards making things *more* correct by removing possible miscompilations.
Currently, InstCombine simply consumes these selects into and/or of i1 (which is also unsafe), so the visible effect would be very small. The unsafe select -> and/or transformation will be removed in the future.
There has been efforts for updating optimizations to support the select form as well, and they are linked to D93065.

The safe transformation is fired when it is called by SimplifyCFG only. This is done by setting the new `PoisonSafe` argument as true.
Another place that calls FoldBranchToCommonDest is LoopSimplify. `PoisonSafe` flag is set to false in this case because enabling it has a nontrivial impact in performance because SCEV is more conservative with select form and InductiveRangeCheckElimination isn't aware of select form of and/or i1.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D95026

[SimplifyCFG] Teach FoldBranchToCommonDest() to preserve DomTree, part 1

2020-12-19T21:18:36+00:00

... for conditional branch case

[NFCI][SimlifyCFG] simplifyOnce(): also perform DomTree validation

2020-12-19T21:18:32+00:00

And that exposes that a number of tests don't *actually* manage to
maintain DomTree validity, which is inline with my observations.

Once again, SimlifyCFG pass currently does not require/preserve DomTree
by default, so this is effectively NFC.

[SimplifyCFG] DeleteDeadBlock() already knows how to preserve DomTree

2020-12-17T21:37:21+00:00

... so just ensure that we pass DomTreeUpdater it into it.

Fixes DomTree preservation for a large number of tests,
all of which are marked as such so that they do not regress.

[SimplifyCFG] Preserve !annotation in FoldBranchToCommonDest.

2020-12-17T14:06:58+00:00

When folding a branch to a common destination, preserve !annotation on
the created instruction, if the terminator of the BB that is going to be
removed has !annotation. This should ensure that !annotation is attached
to the instructions that 'replace' the original terminator.

Reviewed By: jdoerfert, lebedev.ri

Differential Revision: https://reviews.llvm.org/D93410

[SimplifyCFG] Precommit test for preserving !annotation.

2020-12-16T18:47:45+00:00