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x64: Add a smattering of lowerings for shuffle specializations (#5930)

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* x64: Add lowerings for `punpck{h,l}wd`

Add some special cases for `shuffle` for more specialized x86
instructions.

* x64: Add `shuffle` lowerings for `pshufd`

This commit adds special-cased lowerings for the x64 `shuffle`
instruction when the `pshufd` instruction alone is necessary. This is
possible when the shuffle immediate permutes 32-bit values within one of
the vector inputs of the `shuffle` instruction, but not both.

* x64: Add shuffle lowerings for `punpck{h,l}{q,}dq`

This adds specific permutations for some x86 instructions which
specifically interleave high/low bytes for 32 and 64-bit values. This
corresponds to the preexisting specific lowerings for interleaving 8 and
16-bit values.

* x64: Add `shuffle` lowerings for `shufps`

This commit adds targeted lowerings for the `shuffle` instruction that
match the pattern that `shufps` supports. The `shufps` instruction
selects two elements from the first vector and two elements from the
second vector which means while it's not generally applicable it should
still be more useful than the catch-all lowering of `shuffle`.

* x64: Add shuffle support for `pshuf{l,h}w`

This commit adds special lowering cases for these instructions which
permute 16-bit values within a 128-bit value either within the upper or
lower half of the 128-bit value.

* x64: Specialize `shuffle` with an all-zeros immediate

Instead of loading the all-zeros immediate from a rip-relative address
at the end of the function instead generate a zero with a `pxor`
instruction and then use `pshufb` to do the broadcast.

* Review comments
This commit is contained in:
Alex Crichton
2023-03-09 16:58:19 -06:00
committed by GitHub
parent 8a2bf29444
commit 1c3a1bda6c
10 changed files with 1332 additions and 10 deletions
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cranelift/codegen/src/prelude_lower.isle
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@@ -592,6 +592,16 @@
(decl u64_from_constant (u64) Constant)
(extern extractor u64_from_constant u64_from_constant)
;; Extracts lane indices, represented as u8's, if the immediate for a
;; `shuffle` instruction represents shuffling N-bit values. The u8 values
;; returned will be in the range of 0 to (256/N)-1, inclusive, and index the
;; N-bit chunks of two concatenated 128-bit vectors starting from the
;; least-significant bits.
(decl shuffle32_from_imm (u8 u8 u8 u8) Immediate)
(extern extractor shuffle32_from_imm shuffle32_from_imm)
(decl shuffle16_from_imm (u8 u8 u8 u8 u8 u8 u8 u8) Immediate)
(extern extractor shuffle16_from_imm shuffle16_from_imm)
;;;; Helpers for generating returns ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Extractor to check for the special case that a `WritableValueRegs`