[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] Add ADDW/AND/OR/XOR/SUB/SUBW to getRegAllocHints.

These instructions requires both register operands to be compressible
so I've only applied the hint if we already have a GPRC physical regis

[RISCV] Add ADDW/AND/OR/XOR/SUB/SUBW to getRegAllocHints.

These instructions requires both register operands to be compressible
so I've only applied the hint if we already have a GPRC physical register
assigned for the other register operand.

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D139079

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[DAG] visitXOR - fold XOR(A,B) -> OR(A,B) iff A and B have no common bits

Alive2: https://alive2.llvm.org/ce/z/7wvfns

Part of Issue #58624

[RISCV][NFC] Reorganize check prefixes in some tests to reduce redundant lines

Reviewed By: benshi001, craig.topper, frasercrmck

Differential Revision: https://reviews.llvm.org/D123176

[RISCV] Update recently ratified Zb{a,b,c,s} extensions to no longer be experimental

Agreed policy is that RISC-V extensions that have not yet been ratified
should be marked as experimental, and ena

[RISCV] Update recently ratified Zb{a,b,c,s} extensions to no longer be experimental

Agreed policy is that RISC-V extensions that have not yet been ratified
should be marked as experimental, and enabling them requires the use of
the -menable-experimental-extensions flag when using clang alongside the
version number. These extensions have now been ratified, so this is no
longer necessary, and the target feature names can be renamed to no
longer be prefixed with "experimental-".

Differential Revision: https://reviews.llvm.org/D117131

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[RISCV] Reverse the order of loading/storing callee-saved registers.

Currently, we restore the return address register as the last restoring
instruction in the epilog. The next instruction is `ret`

[RISCV] Reverse the order of loading/storing callee-saved registers.

Currently, we restore the return address register as the last restoring
instruction in the epilog. The next instruction is `ret` usually. It is
a use of return address register. In some microarchitectures, there is
load-to-use data hazard. To avoid the load-to-use data hazard, we could
separate the load instruction from its use as far as possible. In this
patch, we reverse the order of restoring callee-saved registers to
increase the distance of `load ra` and `ret` in the epilog.

Differential Revision: https://reviews.llvm.org/D113967

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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] Override TargetLowering::hasAndNot for Zbb.

Differential Revision: https://reviews.llvm.org/D113937

[RISCV] Add test cases to prepare for overring TargetLowering::hasAndNot. NFC

These test files are copied directly from AArch64. Some of the cases
may benefit from ANDN with the Zbb extension. Somes

[RISCV] Add test cases to prepare for overring TargetLowering::hasAndNot. NFC

These test files are copied directly from AArch64. Some of the cases
may benefit from ANDN with the Zbb extension. Somes cases already
improve use ANDN.

selectcc-to-shiftand.ll also contains tests that test select->and
conversion even when a ANDN isn't needed. I think this improves our
coverage of these optimizations.

Differential Revision: https://reviews.llvm.org/D113935

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