[RISCV] Enable bidirectional scheduling and tracking register pressure (#115445)


This is based on other targets like PPC/AArch64 and some experiments.

This PR will only enable bidirectional schedu

[RISCV] Enable bidirectional scheduling and tracking register pressure (#115445)


This is based on other targets like PPC/AArch64 and some experiments.

This PR will only enable bidirectional scheduling and tracking register
pressure.

Disclaimer: I haven't tested it on many cores, maybe we should make
some options being features. I believe downstreams must have tried
this before, so feedbacks are welcome.

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[RISCV] Omit "@plt" in assembly output "call foo@plt" (#72467)

R_RISCV_CALL/R_RISCV_CALL_PLT distinction is not necessary and
R_RISCV_CALL has been deprecated. Since https://reviews.llvm.org/D132530

[RISCV] Omit "@plt" in assembly output "call foo@plt" (#72467)

R_RISCV_CALL/R_RISCV_CALL_PLT distinction is not necessary and
R_RISCV_CALL has been deprecated. Since https://reviews.llvm.org/D132530
`call foo` assembles to R_RISCV_CALL_PLT. The `@plt` suffix is not
useful and can be removed now (matching AArch64 and PowerPC).

GNU assembler assembles `call foo` to RISCV_CALL_PLT since 2022-09
(70f35d72ef04cd23771875c1661c9975044a749c).

Without this patch, unconditionally changing MO_CALL to MO_PLT could
create `jump .L1@plt, a0`, which is invalid in LLVM integrated assembler
and GNU assembler.

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[RISCV] Strip W suffix from ADDIW (#68425)

The motivation of this change is simply to reduce test duplication. As
can be seen in the (massive) test delta, we have many tests whose output
differ on

[RISCV] Strip W suffix from ADDIW (#68425)

The motivation of this change is simply to reduce test duplication. As
can be seen in the (massive) test delta, we have many tests whose output
differ only due to the use of addi on rv32 vs addiw on rv64 when the
high bits are don't care.

As an aside, we don't need to worry about the non-zero immediate
restriction on the compressed variants because we're not directly
forming the compressed variants. If we happen to get a zero immediate
for the ADDI, then either a later optimization will strip the useless
instruction or the encoder is responsible for not compressing the
instruction.

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[RISCV] Add pass to remove W suffix from ADDIW and SLLIW to improve compressibility

SLLI and ADD are more compressible than SLLIW and ADDW. SLLI/ADD both have a 5-bit register encoding. SLLIW/ADDW h

[RISCV] Add pass to remove W suffix from ADDIW and SLLIW to improve compressibility

SLLI and ADD are more compressible than SLLIW and ADDW. SLLI/ADD both have a 5-bit register encoding. SLLIW/ADDW have a 3-bit register encoding. They both require the dest to also be one of the sources.

We aggressively form ADDW/SLLIW as it helps hasAllWBitUsers in RISCVISelDAGToDAG to not require recursion. So we need a pass to remove excessive -w suffixes.

Differential Revision: https://reviews.llvm.org/D139948

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[RISCV][CodeGen][SelectionDAG] Recursively check hasAllNBitUsers for logical machine opcodes

We don’t have W versions of AND/OR/XOR/ANDN/ORN/XNOR so we should recursively check their users. We shoul

[RISCV][CodeGen][SelectionDAG] Recursively check hasAllNBitUsers for logical machine opcodes

We don’t have W versions of AND/OR/XOR/ANDN/ORN/XNOR so we should recursively check their users. We should limit the recursion to SelectionDAG::MaxRecursionDepth levels.

We need to add a Depth argument, all existing callers should pass 0 to the Depth. The new recursive calls should increment it by 1. At the top of the function we should give up and return false if Depth >= SelectionDAG::MaxRecursionDepth.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D139462

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[RISCV] Implement isUsedByReturnOnly TargetLowering hook in order to tailcall more libcalls

Prior to this patch, libcalls inserted by the SelectionDAG legalizer
could never be tailcalled. The eligib

[RISCV] Implement isUsedByReturnOnly TargetLowering hook in order to tailcall more libcalls

Prior to this patch, libcalls inserted by the SelectionDAG legalizer
could never be tailcalled. The eligibility of libcalls for tail calling
is is partly determined by checking TargetLowering::isInTailCallPosition
and comparing the return type of the libcall and the calleer.
isInTailCallPosition in turn calls TargetLowering::isUsedByReturnOnly
(which always returns false if not implemented by the target).

This patch provides a minimal implementation of
TargetLowering::isUsedByReturnOnly - enough to support tail calling
libcalls on hard float ABIs. Soft-float ABIs are left for a follow on
patch. libcall-tail-calls.ll also shows missed opportunities to tail
call integer libcalls, but this is due to issues outside of
the isUsedByReturnOnly hook.

Differential Revision: https://reviews.llvm.org/D131087

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[RISCV] Use shift for zero extension when Zbb and Zbp are not enabled

Now AND is used for zero extension when both Zbb and Zbp are not enabled.
It may be better to use shift operation if the trailin

[RISCV] Use shift for zero extension when Zbb and Zbp are not enabled

Now AND is used for zero extension when both Zbb and Zbp are not enabled.
It may be better to use shift operation if the trailing ones mask exceeds simm12.

This patch optimzes LUI+ADDI+AND to SLLI+SRLI.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D116720

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[RISCV] Generate pseudo instruction li

Add an alias of `addi [x], zero, imm` to generate pseudo
instruction li, which makes assembly mush more readable.
For existed tests, users can update them by r

[RISCV] Generate pseudo instruction li

Add an alias of `addi [x], zero, imm` to generate pseudo
instruction li, which makes assembly mush more readable.
For existed tests, users can update them by running script
`llvm/utils/update_llc_test_checks.py`.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D112692

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[RISCV] Add custom isel to select (and (srl X, C1), C2) and (and (shl X, C1), C2)

Replace some existing isel patterns that are covered by the new
code. SLLIUWPat has been removed in favor of folding

[RISCV] Add custom isel to select (and (srl X, C1), C2) and (and (shl X, C1), C2)

Replace some existing isel patterns that are covered by the new
code. SLLIUWPat has been removed in favor of folding its root case
into the new code. The other uses in isel patterns for shXadd.uw
have been switched to using hardcoded AND masks.

This is based on the original version of D49585 from ARM. The final
version of that was made a DAG combine, but I've chosen to keep it
as custom isel. I'm not convinced DAG combine is as good with
shift pairs as it is with and+shift. I saw some issues optimizing
the shifts created by vscale lowering if an and isn't created for
from a shift pair.

Reviewed By: luismarques

Differential Revision: https://reviews.llvm.org/D106230

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[RISCV] Add more i32 srem/sdiv with power of 2 constant tests. NFC

Add a small power 2 srem test to match existing sdiv test. Add
larger power of 2 test to both.

The larger constant test shows mate

[RISCV] Add more i32 srem/sdiv with power of 2 constant tests. NFC

Add a small power 2 srem test to match existing sdiv test. Add
larger power of 2 test to both.

The larger constant test shows materialization of a constant
for an AND in the RV64 code. We should be using W shift instructions
to match the RV32 code.

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[RISCV] Use DIVUW/REMUW/DIVW instructions for i8/i16/i32 udiv/urem/sdiv when LHS is constant.

We don't really have optimizations for division with a constant
LHS. If we don't use a W instruction we

[RISCV] Use DIVUW/REMUW/DIVW instructions for i8/i16/i32 udiv/urem/sdiv when LHS is constant.

We don't really have optimizations for division with a constant
LHS. If we don't use a W instruction we end up needing to sign
or zero extend the RHS to use the 64-bit instruction.

I had to sign_extend i32 constants on the LHS instead of using
any_extend which becomes zero_extend. If we don't do this, constants
that were originally negative become harder to materialize. I think
this problem exists for more of our W instruction cases. For example
(i32 (shl -1, X)), but we don't have lit tests. I'll work on that
as a follow up.

I also left a FIXME for enabling W instruction for RHS constants
under -Oz.

Reviewed By: luismarques

Differential Revision: https://reviews.llvm.org/D105769

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[RISCV] Restore non-constant srem test I accidentally deleted. NFC

[RISCV] Add test cases for div/rem with constant left hand side. NFC

Some of these would produce better code if we used W instructions,
but constant LHS currently prevents that.

[RISCV] Use ComputeNumSignBits/MaskedValueIsZero in RISCVDAGToDAGISel::selectSExti32/selectZExti32.

This helps us select W instructions in more cases. Most of the
affected tests have had the sign_ex

[RISCV] Use ComputeNumSignBits/MaskedValueIsZero in RISCVDAGToDAGISel::selectSExti32/selectZExti32.

This helps us select W instructions in more cases. Most of the
affected tests have had the sign_extend_inreg or AND folded into
sextload/zextload.

Differential Revision: https://reviews.llvm.org/D104079

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[RISCV] Add i8/i16 test cases to div.ll and i8/i16/i64 to rem.ll. NFC

This improves our coverage of these operations and shows that we
use really large constants for division by constant on i8/i16
e

[RISCV] Add i8/i16 test cases to div.ll and i8/i16/i64 to rem.ll. NFC

This improves our coverage of these operations and shows that we
use really large constants for division by constant on i8/i16
especially on RV64. The issue is that BuildSDIV/BuildUDIV are
limited to legal types so we have to promote to i64 before it
kicks in. At that point we've lost the range information for the
original type.

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[RISCV][NFC] Regenerate RISCV CodeGen tests

Regenerated using:

./llvm/utils/update_llc_test_checks.py -u llvm/test/CodeGen/RISCV/*.ll

This has added comments to spill-related instructions and adde

[RISCV][NFC] Regenerate RISCV CodeGen tests

Regenerated using:

./llvm/utils/update_llc_test_checks.py -u llvm/test/CodeGen/RISCV/*.ll

This has added comments to spill-related instructions and added @plt to
some symbols.

Differential Revision: https://reviews.llvm.org/D92841

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[RISCV] Introduce codegen patterns for RV64M-only instructions

As discussed on llvm-dev
<http://lists.llvm.org/pipermail/llvm-dev/2018-December/128497.html>, we have
to be careful when trying to sel

[RISCV] Introduce codegen patterns for RV64M-only instructions

As discussed on llvm-dev
<http://lists.llvm.org/pipermail/llvm-dev/2018-December/128497.html>, we have
to be careful when trying to select the *w RV64M instructions. i32 is not a
legal type for RV64 in the RISC-V backend, so operations have been promoted by
the time they reach instruction selection. Information about whether the
operation was originally a 32-bit operations has been lost, and it's easy to
write incorrect patterns.

Similarly to the variable 32-bit shifts, a DAG combine on ANY_EXTEND will
produce a SIGN_EXTEND if this is likely to result in sdiv/udiv/urem being
selected (and so save instructions to sext/zext the input operands).

Differential Revision: https://reviews.llvm.org/D53230

llvm-svn: 350993

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[RISCV] Expand function call to "call" pseudoinstruction

To do this:
1. Change GlobalAddress SDNode to TargetGlobalAddress to avoid legalizer
split the symbol.

2. Change ExternalSymbol SDNode to

[RISCV] Expand function call to "call" pseudoinstruction

To do this:
1. Change GlobalAddress SDNode to TargetGlobalAddress to avoid legalizer
split the symbol.

2. Change ExternalSymbol SDNode to TargetExternalSymbol to avoid legalizer
split the symbol.

3. Let PseudoCALL match direct call with target operand TargetGlobalAddress
and TargetExternalSymbol.

Differential Revision: https://reviews.llvm.org/D44885

llvm-svn: 330827

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[RISCV] Codegen support for the standard RV32M instruction set extension

llvm-svn: 322843

[RISCV] Implement frame pointer elimination

llvm-svn: 322839

[RISCV] Enable emission of alias instructions by default

This patch switches the default for -riscv-no-aliases to false
and updates all affected MC and CodeGen tests. As recommended in
D41071, MC te

[RISCV] Enable emission of alias instructions by default

This patch switches the default for -riscv-no-aliases to false
and updates all affected MC and CodeGen tests. As recommended in
D41071, MC tests use the canonical instructions and the CodeGen
tests use the aliases.

Additionally, for the f and d instructions with rounding mode,
the tests for the aliased versions are moved and tightened such
that they can actually detect if alias emission is enabled.
(see D40902 for context)

Differential Revision: https://reviews.llvm.org/D41225

Patch by Mario Werner.

llvm-svn: 320797

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[RISCV] Implement prolog and epilog insertion

As frame pointer elimination isn't implemented until a later patch and we make
extensive use of update_llc_test_checks.py, this changes touches a lot o

[RISCV] Implement prolog and epilog insertion

As frame pointer elimination isn't implemented until a later patch and we make
extensive use of update_llc_test_checks.py, this changes touches a lot of the
RISC-V tests.

Differential Revision: https://reviews.llvm.org/D39849

llvm-svn: 320357

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[RISCV] Support lowering FrameIndex

Introduces the AddrFI "addressing mode", which is necessary simply because
it's not possible to write a pattern that directly matches a frameindex.

Ensure calle

[RISCV] Support lowering FrameIndex

Introduces the AddrFI "addressing mode", which is necessary simply because
it's not possible to write a pattern that directly matches a frameindex.

Ensure callee-saved registers are accessed relative to the stackpointer. This
is necessary as callee-saved register spills are performed before the frame
pointer is set.

Move HexagonDAGToDAGISel::isOrEquivalentToAdd to SelectionDAGISel, so we can
make use of it in the RISC-V backend.

Differential Revision: https://reviews.llvm.org/D39848

llvm-svn: 320353

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[CodeGen] Unify MBB reference format in both MIR and debug output

As part of the unification of the debug format and the MIR format, print
MBB references as '%bb.5'.

The MIR printer prints the IR n

[CodeGen] Unify MBB reference format in both MIR and debug output

As part of the unification of the debug format and the MIR format, print
MBB references as '%bb.5'.

The MIR printer prints the IR name of a MBB only for block definitions.

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)->getNumber\(\)/" << printMBBReference(*\1)/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)\.getNumber\(\)/" << printMBBReference(\1)/g'
* find . \( -name "*.txt" -o -name "*.s" -o -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#([0-9]+)/%bb.\1/g'
* grep -nr 'BB#' and fix

Differential Revision: https://reviews.llvm.org/D40422

llvm-svn: 319665

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[RISCV] Support and tests for a variety of additional LLVM IR constructs

Previous patches primarily ensured that codegen was possible for the standard
RISC-V instructions. However, there are a numbe

[RISCV] Support and tests for a variety of additional LLVM IR constructs

Previous patches primarily ensured that codegen was possible for the standard
RISC-V instructions. However, there are a number of IR inputs that wouldn't be
appropriately lowered. This patch both adds test cases and supports lowering
for a number of these cases:
* Improved sext/zext/trunc support
* Support for setcc variants that don't map directly to RISC-V instructions
* Lowering mul, and hence support for external symbols
* addc, adde, subc, sube
* mulhs, srem, mulhu, urem, udiv, sdiv
* {srl,sra,shl}_parts
* brind
* br_jt
* bswap, ctlz, cttz, ctpop
* rotl, rotr
* BlockAddress operands

Differential Revision: https://reviews.llvm.org/D29938

llvm-svn: 318737

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