[DAG] SimplifyDemandedBits - AND/OR/XOR - attempt basic knownbits simplifications before calling SimplifyMultipleUseDemandedBits

Noticed while investigating the SystemZ regressions in D77804, prefer

[DAG] SimplifyDemandedBits - AND/OR/XOR - attempt basic knownbits simplifications before calling SimplifyMultipleUseDemandedBits

Noticed while investigating the SystemZ regressions in D77804, prefer handling the knownbits analysis/simplification in the bitop nodes directly before falling back to SimplifyMultipleUseDemandedBits

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[DAG] Fold (shl (srl x, c), c) -> and(x, m) even if srl has other uses

If we're using shift pairs to mask, then relax the one use limit if the shift amounts are equal - we'll only be generating a si

[DAG] Fold (shl (srl x, c), c) -> and(x, m) even if srl has other uses

If we're using shift pairs to mask, then relax the one use limit if the shift amounts are equal - we'll only be generating a single AND node.

AArch64 has a couple of regressions due to this, so I've enforced the existing one use limit inside a AArch64TargetLowering::shouldFoldConstantShiftPairToMask callback.

Part of the work to fix the regressions in D77804

Differential Revision: https://reviews.llvm.org/D125607

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[DAG] Enable ISD::SHL SimplifyMultipleUseDemandedBits handling inside SimplifyDemandedBits

Pulled out of D77804 as its going to be easier to address the regressions individually.

This patch allows

[DAG] Enable ISD::SHL SimplifyMultipleUseDemandedBits handling inside SimplifyDemandedBits

Pulled out of D77804 as its going to be easier to address the regressions individually.

This patch allows SimplifyDemandedBits to call SimplifyMultipleUseDemandedBits in cases where the source operand has other uses, enabling us to peek through the shifted value if we don't demand all the bits/elts.

The lost RISCV gorc2 fold shouldn't be a problem - instcombine would have already destroyed that pattern - see https://github.com/llvm/llvm-project/issues/50553

Differential Revision: https://reviews.llvm.org/D124839

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[LegalizeTypes] Scalarize non-byte sized loads in WidenRecRes_Load and SplitVecResLoad

Should fix PR42803 and PR44902

Differential Revision: https://reviews.llvm.org/D74590

[SystemZ] Regenerate <8 x i31> store test

To help show the diffs from an upcoming SimplifyDemandedBits patch.

llvm-svn: 367216

[TargetLowering] Add SimplifyMultipleUseDemandedBits

This patch introduces the DAG version of SimplifyMultipleUseDemandedBits, which attempts to peek through ops (mainly and/or/xor so far) that don'

[TargetLowering] Add SimplifyMultipleUseDemandedBits

This patch introduces the DAG version of SimplifyMultipleUseDemandedBits, which attempts to peek through ops (mainly and/or/xor so far) that don't contribute to the demandedbits/elts of a node - which means we can do this even in cases where we have multiple uses of an op, which normally requires us to demanded all bits/elts. The intention is to remove a similar instruction - SelectionDAG::GetDemandedBits - once SimplifyMultipleUseDemandedBits has matured.

The InstCombine version of SimplifyMultipleUseDemandedBits can constant fold which I haven't added here yet, and so far I've only wired this up to some basic binops (and/or/xor/add/sub/mul) to demonstrate its use.

We do see a couple of regressions that need to be addressed:

AMDGPU unsigned dot product codegen retains an AND mask (for ZERO_EXTEND) that it previously removed (but otherwise the dotproduct codegen is a lot better).

X86/AVX2 has poor handling of vector ANY_EXTEND/ANY_EXTEND_VECTOR_INREG - it prematurely gets converted to ZERO_EXTEND_VECTOR_INREG.

The code owners have confirmed its ok for these cases to fixed up in future patches.

Differential Revision: https://reviews.llvm.org/D63281

llvm-svn: 366799

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[SystemZ, RegAlloc] Favor 3-address instructions during instruction selection.

This patch aims to reduce spilling and register moves by using the 3-address
versions of instructions per default inst

[SystemZ, RegAlloc] Favor 3-address instructions during instruction selection.

This patch aims to reduce spilling and register moves by using the 3-address
versions of instructions per default instead of the 2-address equivalent
ones. It seems that both spilling and register moves are improved noticeably
generally.

Regalloc hints are passed to increase conversions to 2-address instructions
which are done in SystemZShortenInst.cpp (after regalloc).

Since the SystemZ reg/mem instructions are 2-address (dst and lhs regs are
the same), foldMemoryOperandImpl() can no longer trivially fold a spilled
source register since the reg/reg instruction is now 3-address. In order to
remedy this, new 3-address pseudo memory instructions are used to perform the
folding only when the dst and lhs virtual registers are known to be allocated
to the same physreg. In order to not let MachineCopyPropagation run and
change registers on these transformed instructions (making it 3-address), a
new target pass called SystemZPostRewrite.cpp is run just after
VirtRegRewriter, that immediately lowers the pseudo to a target instruction.

If it would have been possibe to insert a COPY instruction and change a
register operand (convert to 2-address) in foldMemoryOperandImpl() while
trusting that the caller (e.g. InlineSpiller) would update/repair the
involved LiveIntervals, the solution involving pseudo instructions would not
have been needed. This is perhaps a potential improvement (see Phabricator
post).

Common code changes:

* A new hook TargetPassConfig::addPostRewrite() is utilized to be able to run a
target pass immediately before MachineCopyPropagation.

* VirtRegMap is passed as an argument to foldMemoryOperand().

Review: Ulrich Weigand, Quentin Colombet
https://reviews.llvm.org/D60888

llvm-svn: 362868

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[DAGCombine] Improve Load-Store Forwarding

Summary:
Extend analysis forwarding loads from preceeding stores to work with
extended loads and truncated stores to the same address so long as the
load i

[DAGCombine] Improve Load-Store Forwarding

Summary:
Extend analysis forwarding loads from preceeding stores to work with
extended loads and truncated stores to the same address so long as the
load is fully subsumed by the store.

Hexagon's swp-epilog-phis.ll and swp-memrefs-epilog1.ll test are
deleted as they've no longer seem to be relevant.

Reviewers: RKSimon, rnk, kparzysz, javed.absar

Subscribers: sdardis, nemanjai, hiraditya, atanasyan, llvm-commits

Differential Revision: https://reviews.llvm.org/D49200

llvm-svn: 344142

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[SystemZ] Reimplent SchedModel IssueWidth and WriteRes/ReadAdvance mappings.

As a consequence of recent discussions
(http://lists.llvm.org/pipermail/llvm-dev/2018-May/123164.html), this patch
change

[SystemZ] Reimplent SchedModel IssueWidth and WriteRes/ReadAdvance mappings.

As a consequence of recent discussions
(http://lists.llvm.org/pipermail/llvm-dev/2018-May/123164.html), this patch
changes the SystemZ SchedModels so that the IssueWidth is 6, which is the
decoder capacity, and NumMicroOps become the number of decoder slots needed
per instruction.

In addition, the SchedWrite latencies now match the MachineInstructions
def-operand indexes, and ReadAdvances have been added on instructions with
one register operand and one memory operand.

Review: Ulrich Weigand
https://reviews.llvm.org/D47008

llvm-svn: 337538

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[SelectionDAG] Consider endianness in scalarizeVectorStore().

When handling vectors with non byte-sized elements, reverse the order of the
elements in the built integer if the target is Big-Endian.

[SelectionDAG] Consider endianness in scalarizeVectorStore().

When handling vectors with non byte-sized elements, reverse the order of the
elements in the built integer if the target is Big-Endian.

SystemZ tests updated.

Review: Eli Friedman, Ulrich Weigand.
https://reviews.llvm.org/D42786

llvm-svn: 324063

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Followup on Proposal to move MIR physical register namespace to '$' sigil.

Discussed here:

http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html

In preparation for adding support for n

Followup on Proposal to move MIR physical register namespace to '$' sigil.

Discussed here:

http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html

In preparation for adding support for named vregs we are changing the sigil for
physical registers in MIR to '$' from '%'. This will prevent name clashes of
named physical register with named vregs.

llvm-svn: 323922

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Move new test from Generic to SystemZ.

A few build bots failed with r323042 because they are not configured to
build the SystemZ target.

llvm-svn: 323044