Currently, a node and its users are added back to the worklist in reverse topological order after it is combined. This diff changes that order to be topological. This is part of a larger migration to get the DAGCombiner to process nodes in topological order.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D127115
Use computeOverflowForUnsignedAdd and computeOverflowForSignedAdd
instead. Unfortunately, this recomputes some known bits and sign bits
we may have already computed, but was the easiest fix without a lot
of restructuring.
This recovers the regressions from D151472.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D151858
This reverts commit 0a762ec1b09d96734a3462f8792a5574d089b24d.
Some CPUs enable fp64 by default (such as cortex-m7). When specifying a
single-precision fpu with them like -mfpu=fpv5-sp-d16, the fp64 feature will
be disabled, but fpreg64 will not. We need to disable them both correctly under
clang in order for the backend to be able to use the reliably. In the meantime
this reverts 0a762ec1b09d96734 until that issue is fixed.
Given an insert of a scalar load into a vector shuffle with mask
u,0,1,2,3,4,5,6 or 1,2,3,4,5,6,7,u (depending on the insert index),
it can be more profitable to convert to a single load and avoid the
shuffles. This adds a DAG combine for it, providing the new load is
still fast.
Differential Revision: https://reviews.llvm.org/D151029
Code generated with -Ofast and -O3 -ffp-contract=fast (add
-ffinite-math-only to enable vectorization) can differ significantly.
Code compiled with -O3 can be deinterleaved using patterns as the
instruction order is preserved. However, with the -Ofast flag, there
can be multiple changes in the computation sequence, and even the real
and imaginary parts may not be calculated in parallel.
For more details, refer to
llvm/test/CodeGen/AArch64/complex-deinterleaving-*-fast.ll and
llvm/test/CodeGen/AArch64/complex-deinterleaving-*-contract.ll tests.
This patch implements a more general approach and enables handling most
-Ofast cases.
Differential Revision: https://reviews.llvm.org/D148558
This exposed a miscompile due to incorrect flag preservation in
integer type legalization, which has been fixed in D151472.
-----
This patch is a continuation of D150110. It separates the cases for
ADD and SUB into their own cases so that computeForAddSub can be
directly called and the NSW flag passed. This allows better
optimization when the NSW flag is enabled, and allows fixing up the
TODO that was there previously in SimplifyDemandedBits.
Differential Revision: https://reviews.llvm.org/D150769
This was originally added to preserve FMF on SETCC. Unfortunately,
it also incorrectly preserves nuw/nsw on ADD/SUB in some cases.
There's also no guarantee the new opcode is even the same opcode
as the original node.
This patch removes the code and adds code to explicitly preserve
FMF flags in the SETCC promotion function.
The other test changes are from nuw/nsw not being preserved. I
believe for all these tests it was correct to preserve the flags,
so we need new code to preserve the flags when possible. I'll post
another patch for that since it's a riskier change.
This should unblock D150769.
Differential Revision: https://reviews.llvm.org/D151472
This is an attempt to reland D42600 and enabling this optimisation by default.
This also resolves the issue pointed out in the context of PGO build.
Differential Revision: https://reviews.llvm.org/D42600
There are two motivations.
`-fno-pic -fstack-protector -mstack-protector-guard=global` created
`__stack_chk_guard` is referenced directly on all ELF OSes except FreeBSD.
This patch allows referencing the symbol indirectly with
-fno-direct-access-external-data.
Some Linux kernel folks want
`-fno-pic -fstack-protector -mstack-protector-guard-reg=gs -mstack-protector-guard-symbol=__stack_chk_guard`
created `__stack_chk_guard` to be referenced directly, avoiding
R_X86_64_REX_GOTPCRELX (even if the relocation may be optimized out by the linker).
https://github.com/llvm/llvm-project/issues/60116
Why they need this isn't so clear to me.
---
Add module flag "direct-access-external-data" and set the dso_local property of
the stack protector symbol. The module flag can benefit other LLVMCodeGen
synthesized symbols that are not represented in LLVM IR.
Nowadays, with `-fno-pic` being uncommon, ideally we should set
"direct-access-external-data" when it is true. However, doing so would require
~90 clang/test tests to be updated, which are too much.
As a compromise, we set "direct-access-external-data" only when it's different
from the implied default value.
Reviewed By: nickdesaulniers
Differential Revision: https://reviews.llvm.org/D150841
We can compute a simpler expression for Lo for these cases. This
is an alternative for the test cases in D151180 that works for
more targets.
This is similar to some of the special cases we have for expanding
setcc operands.
Differential Revision: https://reviews.llvm.org/D151182
This is a follow-up to b71edfaa4ec3c998aadb35255ce2f60bba2940b0
since I forgot the lit.local.cfg files in that one.
Reformatting is done with `black`.
If you end up having problems merging this commit because you
have made changes to a python file, the best way to handle that
is to run git checkout --ours <yourfile> and then reformat it
with black.
If you run into any problems, post to discourse about it and
we will try to help.
RFC Thread below:
https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Reviewed By: barannikov88, kwk
Differential Revision: https://reviews.llvm.org/D150762
This patch is a continuation of D150110. It separates the cases for
ADD and SUB into their own cases so that computeForAddSub can be
directly called and the NSW flag passed. This allows better
optimization when the NSW flag is enabled, and allows fixing up the
TODO that was there previously in SimplifyDemandedBits.
Differential Revision: https://reviews.llvm.org/D150769
This reverts commit 1ddfd1c8186735c62b642df05c505dc4907ffac4.
The original commit causes a Chrome build assertion failure with
ThinLTO: https://crbug.com/1443635
Assuming that the stack grows downwards, it is fine if the stack
pointer is exactly at the stacklet boundary. We should use
less-or-equal condition when deciding whether to skip new memory
allocation.
Differential Revision: https://reviews.llvm.org/D149315
This uses the patterns defined in MVE_TwoOpPattern to add predicated patterns
for vshls/u instructions.
Differnetial Revision: https://reviews.llvm.org/D149366
This function gets called for vectors and ISD::SELECT_CC was never
intended to support vectors. Some updates were made to support
it when this function started getting used for vectors.
Overall, using separate ISD::SETCC and ISD::SELECT looks like an
improvement even for scalar.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D149481
We already have tablegen patterns for a lot of these, but performing the
combine earlier in DAG can help in a few extra cases.
Differential Revision: https://reviews.llvm.org/D149269
This patch splits a restore point to allow it to only post-dominate blocks reachable by use
or def of CSRs(Callee Saved Registers)/FI(Frame Index).
Benchmarking this on SPEC2017, this gives around 4% improvement on povray and no significant change
for others.
Co-authored-by: junbuml
Differential Revision: https://reviews.llvm.org/D42600
This adds an extra tablegen combine for folding fadd(a, vcmul(b, c)) into
vcmla(a, b, c), so long as the fadd is allowed to contract.
Differential Revision: https://reviews.llvm.org/D147201
This is the MVE equivalent of https://reviews.llvm.org/D146407. It adds a
target combine for fadd(a, vcmla(b, c, d)) -> vcmla(fadd(a, b), c, d), pushing
the fadd into the operands of the fcmla, which can help simplify away some
additions.
Differential Revision: https://reviews.llvm.org/D147200
The required target features for VMOVSR instruction (integer -> MVE
FP register copy) are HasFPRegs and UseVMOVSR (see
https://reviews.llvm.org/D60694).
The instruction selection pattern must use the same set of
requirements (i.e., HasFPRegs instead of HasVFP2). The discrepancy
can cause instruction selection failure when compiling code for
execute-only position-independence mode.
Reviewed By: dmgreen
Differential Revision: https://reviews.llvm.org/D147523
This attempts to expand the logic in the MVETailPredication pass to convert
active lane masks that the vectorizer produces to vctp instructions that the
backend can later turn into tail predicated loops. Especially for addrecs with
non-zero starts that can be created from epilog vectorization. There is some
adjustment to the logic to handle this, moving some of the code to check the
addrec earlier so that we can get the start value. This start value is then
incorporated into the logic of checkin the new vctp is valid, and there is a
newly added check that it is known to be a multiple of the VF as we expect.
Differential Revision: https://reviews.llvm.org/D146517
Since the redundant BTI instructions emitted by jump tables are now
removed in the ARMBranchTargets pass, the fixupBTI function is not needed
in the ARMConstantIslandPass. Some related tests are removed as well.
The relevant patch that removes the redundant BTI instructions:
https://reviews.llvm.org/D144470
Differential Revision: https://reviews.llvm.org/D145048
Address the dominating condition, the urem fold is benefit from the analytics improvements.
Fix https://github.com/llvm/llvm-project/issues/60546
NOTE: delete the calls in simplifyBinaryIntrinsic and foldICmpWithDominatingICmp
is used to reduce compile time.
Reviewed By: nikic, arsenm, erikdesjardins
Differential Revision: https://reviews.llvm.org/D144248
A BTI instruction was previously inserted at the beginning of each block
that has its address stored in a jump table. Jump tables only emit
indirect jumps in ARM or Thumb1 modes. However, PACBTI is not supported
in these modes. As a result, BTI instructions emitted by jump tables are
redundant. Removing redundant BTI instructions improves the code size
and prevents potential gadgets.
Differential Revision: https://reviews.llvm.org/D144470
Alignment of an alloca in IR can be lower than the preferred alignment
on purpose, but this override essentially treats the preferred
alignment as the minimum alignment.
The patch changes this behavior to always use the specified
alignment. If alignment is not set explicitly in LLVM IR, it is set to
DL.getPrefTypeAlign(Ty) in computeAllocaDefaultAlign.
Tests are changed as well: explicit alignment is increased to match
the preferred alignment if it changes output, or omitted when it is
hard to determine the right value (e.g. for pointers, some structs, or
weird types).
Differential Revision: https://reviews.llvm.org/D135462
So long as the operation is reassociative, we can reassociate the double
vecreduce from for example fadd(vecreduce(a), vecreduce(b)) to
vecreduce(fadd(a,b)). This will in general save a few instructions, but some
architectures (MVE) require the opposite fold, so a shouldExpandReduction is
added to account for it. Only targets that use shouldExpandReduction will be
affected.
Differential Revision: https://reviews.llvm.org/D141870
We have a pass for MVE to perform lane interleaving to make use of top/bottom
instructions, that adds shuffles before extends and after truncates. This
extends it to also start from add reductions, where the order of lanes does not
matter so the shuffle is not needed. We need to be careful about not breaking
the form of existing reductions, but otherwise can save some instructions and
awkward extends.
Differential Revision: https://reviews.llvm.org/D143396
This looks for vaddv(shuffle) or vmlav(shuffle, shuffle), with a shuffle where
all the lanes are used once. Due to the reduction being commutative the shuffle
can be removed.
Differential Revision: https://reviews.llvm.org/D143382
