[JumpThreading] Make test more robust (NFC)

Optimizing away this comparison is not the point of this test,
so make sure it cannot be optimized away.

Infer alignment of unmarked loads in IR/bitcode parsing.

For IR generated by a compiler, this is really simple: you just take the
datalayout from the beginning of the file, and apply it to all the I

Infer alignment of unmarked loads in IR/bitcode parsing.

For IR generated by a compiler, this is really simple: you just take the
datalayout from the beginning of the file, and apply it to all the IR
later in the file. For optimization testcases that don't care about the
datalayout, this is also really simple: we just use the default
datalayout.

The complexity here comes from the fact that some LLVM tools allow
overriding the datalayout: some tools have an explicit flag for this,
some tools will infer a datalayout based on the code generation target.
Supporting this properly required plumbing through a bunch of new
machinery: we want to allow overriding the datalayout after the
datalayout is parsed from the file, but before we use any information
from it. Therefore, IR/bitcode parsing now has a callback to allow tools
to compute the datalayout at the appropriate time.

Not sure if I covered all the LLVM tools that want to use the callback.
(clang? lli? Misc IR manipulation tools like llvm-link?). But this is at
least enough for all the LLVM regression tests, and IR without a
datalayout is not something frontends should generate.

This change had some sort of weird effects for certain CodeGen
regression tests: if the datalayout is overridden with a datalayout with
a different program or stack address space, we now parse IR based on the
overridden datalayout, instead of the one written in the file (or the
default one, if none is specified). This broke a few AVR tests, and one
AMDGPU test.

Outside the CodeGen tests I mentioned, the test changes are all just
fixing CHECK lines and moving around datalayout lines in weird places.

Differential Revision: https://reviews.llvm.org/D78403

show more ...

Temporarily revert "Reapply [LVI] Normalize pointer behavior" and "[LVI] Restructure caching"

This reverts commits 7e18aeba5062cd4324a9efb7bc25c9dbc4a34c2c (D70376) 21fbd5587cdfa11dabb3aeb0ead2d3d5f

Temporarily revert "Reapply [LVI] Normalize pointer behavior" and "[LVI] Restructure caching"

This reverts commits 7e18aeba5062cd4324a9efb7bc25c9dbc4a34c2c (D70376) 21fbd5587cdfa11dabb3aeb0ead2d3d5fd0b490d (D69914) due to increased memory usage.

show more ...

Reapply [LVI] Normalize pointer behavior

This is a rebase of the change over D70376, which fixes an LVI cache
invalidation issue that also affected this patch.

-----

Related to D69686. As noted th

Reapply [LVI] Normalize pointer behavior

This is a rebase of the change over D70376, which fixes an LVI cache
invalidation issue that also affected this patch.

-----

Related to D69686. As noted there, LVI currently behaves differently
for integer and pointer values: For integers, the block value is always
valid inside the basic block, while for pointers it is only valid at
the end of the basic block. I believe the integer behavior is the
correct one, and CVP relies on it via its getConstantRange() uses.

The reason for the special pointer behavior is that LVI checks whether
a pointer is dereferenced in a given basic block and marks it as
non-null in that case. Of course, this information is valid only after
the dereferencing instruction, or in conservative approximation,
at the end of the block.

This patch changes the treatment of dereferencability: Instead of
including it inside the block value, we instead treat it as something
similar to an assume (it essentially is a non-nullness assume) and
incorporate this information in intersectAssumeOrGuardBlockValueConstantRange()
if the context instruction is the terminator of the basic block.
This happens either when determining an edge-value internally in LVI,
or when a terminator was explicitly passed to getValueAt(). The latter
case makes this change not fully NFC, because we can now fold
terminator icmps based on the dereferencability information in the
same block. This is the reason why I changed one JumpThreading test
(it would optimize the condition away without the change).

Of course, we do not want to recompute dereferencability on each
intersectAssume call, so we need a new cache for this. The
dereferencability analysis requires walking the entire basic block
and computing underlying objects of all memory operands. This was
previously done separately for each queried pointer value. In the
new implementation (both because this makes the caching simpler,
and because it is faster), I instead only walk the full BB once and
cache all the dereferenced pointers. So the traversal is now performed
only once per BB, instead of once per queried pointer value.

I think the overall model now makes more sense than before, and there
will be no more pitfalls due to differing integer/pointer behavior.

Differential Revision: https://reviews.llvm.org/D69914

show more ...

Temporarily Revert "Reapply [LVI] Normalize pointer behavior" as it's broken python 3.6.

Reverting to figure out if it's a problem in python or the compiler for now.

This reverts commit 885a05f48a5

Temporarily Revert "Reapply [LVI] Normalize pointer behavior" as it's broken python 3.6.

Reverting to figure out if it's a problem in python or the compiler for now.

This reverts commit 885a05f48a5d320946c89590b73a764e5884fe4f.

show more ...

Reapply [LVI] Normalize pointer behavior

Fix cache invalidation by not guarding the dereferenced pointer cache
erasure by SeenBlocks. SeenBlocks is only populated when actually
caching a value in th

Reapply [LVI] Normalize pointer behavior

Fix cache invalidation by not guarding the dereferenced pointer cache
erasure by SeenBlocks. SeenBlocks is only populated when actually
caching a value in the block, which doesn't necessarily have to happen
just because dereferenced pointers were calculated.

-----

Related to D69686. As noted there, LVI currently behaves differently
for integer and pointer values: For integers, the block value is always
valid inside the basic block, while for pointers it is only valid at
the end of the basic block. I believe the integer behavior is the
correct one, and CVP relies on it via its getConstantRange() uses.

The reason for the special pointer behavior is that LVI checks whether
a pointer is dereferenced in a given basic block and marks it as
non-null in that case. Of course, this information is valid only after
the dereferencing instruction, or in conservative approximation,
at the end of the block.

This patch changes the treatment of dereferencability: Instead of
including it inside the block value, we instead treat it as something
similar to an assume (it essentially is a non-nullness assume) and
incorporate this information in intersectAssumeOrGuardBlockValueConstantRange()
if the context instruction is the terminator of the basic block.
This happens either when determining an edge-value internally in LVI,
or when a terminator was explicitly passed to getValueAt(). The latter
case makes this change not fully NFC, because we can now fold
terminator icmps based on the dereferencability information in the
same block. This is the reason why I changed one JumpThreading test
(it would optimize the condition away without the change).

Of course, we do not want to recompute dereferencability on each
intersectAssume call, so we need a new cache for this. The
dereferencability analysis requires walking the entire basic block
and computing underlying objects of all memory operands. This was
previously done separately for each queried pointer value. In the
new implementation (both because this makes the caching simpler,
and because it is faster), I instead only walk the full BB once and
cache all the dereferenced pointers. So the traversal is now performed
only once per BB, instead of once per queried pointer value.

I think the overall model now makes more sense than before, and there
will be no more pitfalls due to differing integer/pointer behavior.

Differential Revision: https://reviews.llvm.org/D69914

show more ...

Revert "[LVI] Normalize pointer behavior"

This reverts commit 15bc4dc9a8949f9cffd46ec647baf0818d28fb28.

clang-cmake-x86_64-sde-avx512-linux buildbot reported quite a few
compile-time regressions in

Revert "[LVI] Normalize pointer behavior"

This reverts commit 15bc4dc9a8949f9cffd46ec647baf0818d28fb28.

clang-cmake-x86_64-sde-avx512-linux buildbot reported quite a few
compile-time regressions in test-suite, will investigate.

show more ...

[LVI] Normalize pointer behavior

Related to D69686. As noted there, LVI currently behaves differently
for integer and pointer values: For integers, the block value is always
valid inside the basic b

[LVI] Normalize pointer behavior

Related to D69686. As noted there, LVI currently behaves differently
for integer and pointer values: For integers, the block value is always
valid inside the basic block, while for pointers it is only valid at
the end of the basic block. I believe the integer behavior is the
correct one, and CVP relies on it via its getConstantRange() uses.

The reason for the special pointer behavior is that LVI checks whether
a pointer is dereferenced in a given basic block and marks it as
non-null in that case. Of course, this information is valid only after
the dereferencing instruction, or in conservative approximation,
at the end of the block.

This patch changes the treatment of dereferencability: Instead of
including it inside the block value, we instead treat it as something
similar to an assume (it essentially is a non-nullness assume) and
incorporate this information in intersectAssumeOrGuardBlockValueConstantRange()
if the context instruction is the terminator of the basic block.
This happens either when determining an edge-value internally in LVI,
or when a terminator was explicitly passed to getValueAt(). The latter
case makes this change not fully NFC, because we can now fold
terminator icmps based on the dereferencability information in the
same block. This is the reason why I changed one JumpThreading test
(it would optimize the condition away without the change).

Of course, we do not want to recompute dereferencability on each
intersectAssume call, so we need a new cache for this. The
dereferencability analysis requires walking the entire basic block
and computing underlying objects of all memory operands. This was
previously done separately for each queried pointer value. In the
new implementation (both because this makes the caching simpler,
and because it is faster), I instead only walk the full BB once and
cache all the dereferenced pointers. So the traversal is now performed
only once per BB, instead of once per queried pointer value.

I think the overall model now makes more sense than before, and there
will be no more pitfalls due to differing integer/pointer behavior.

Differential Revision: https://reviews.llvm.org/D69914

show more ...

Revert "Temporarily Revert "Add basic loop fusion pass.""

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552

[Local] Make DoesKMove required for combineMetadata.

This patch makes the DoesKMove argument non-optional, to force people
to think about it. Most cases where it is false are either code hoisting
or

[Local] Make DoesKMove required for combineMetadata.

This patch makes the DoesKMove argument non-optional, to force people
to think about it. Most cases where it is false are either code hoisting
or code sinking, where we pick one instruction from a set of
equal instructions among different code paths.

Reviewers: dberlin, nlopes, efriedma, davide

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D47475

llvm-svn: 340606

show more ...