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x64: Peephole optimization for x < 0 (#4625)

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https://github.com/bytecodealliance/wasmtime/pull/4625

Fixes #4607
This commit is contained in:
Trevor Elliott
2022-08-09 09:45:53 -07:00
committed by GitHub
parent a36a52a017
commit ed7dfd3925
3 changed files with 224 additions and 0 deletions
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32
cranelift/codegen/src/isa/x64/lower.isle
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@@ -1501,6 +1501,38 @@
(rule (lower (icmp cc a @ (value_type $I128) b))
(lower_icmp_bool (emit_cmp cc a b)))
;; Peephole optimization for `x < 0`, when x is a signed 64 bit value
(rule (lower (has_type $B1 (icmp (IntCC.SignedLessThan) x @ (value_type $I64) (u64_from_iconst 0))))
(x64_shr $I64 x (Imm8Reg.Imm8 63)))
;; Peephole optimization for `0 > x`, when x is a signed 64 bit value
(rule (lower (has_type $B1 (icmp (IntCC.SignedGreaterThan) (u64_from_iconst 0) x @ (value_type $I64))))
(x64_shr $I64 x (Imm8Reg.Imm8 63)))
;; Peephole optimization for `0 <= x`, when x is a signed 64 bit value
(rule (lower (has_type $B1 (icmp (IntCC.SignedLessThanOrEqual) (u64_from_iconst 0) x @ (value_type $I64))))
(x64_shr $I64 (x64_not $I64 x) (Imm8Reg.Imm8 63)))
;; Peephole optimization for `x >= 0`, when x is a signed 64 bit value
(rule (lower (has_type $B1 (icmp (IntCC.SignedGreaterThanOrEqual) x @ (value_type $I64) (u64_from_iconst 0))))
(x64_shr $I64 (x64_not $I64 x) (Imm8Reg.Imm8 63)))
;; Peephole optimization for `x < 0`, when x is a signed 32 bit value
(rule (lower (has_type $B1 (icmp (IntCC.SignedLessThan) x @ (value_type $I32) (u64_from_iconst 0))))
(x64_shr $I32 x (Imm8Reg.Imm8 31)))
;; Peephole optimization for `0 > x`, when x is a signed 32 bit value
(rule (lower (has_type $B1 (icmp (IntCC.SignedGreaterThan) (u64_from_iconst 0) x @ (value_type $I32))))
(x64_shr $I32 x (Imm8Reg.Imm8 31)))
;; Peephole optimization for `0 <= x`, when x is a signed 32 bit value
(rule (lower (has_type $B1 (icmp (IntCC.SignedLessThanOrEqual) (u64_from_iconst 0) x @ (value_type $I32))))
(x64_shr $I32 (x64_not $I64 x) (Imm8Reg.Imm8 31)))
;; Peephole optimization for `x >= 0`, when x is a signed 32 bit value
(rule (lower (has_type $B1 (icmp (IntCC.SignedGreaterThanOrEqual) x @ (value_type $I32) (u64_from_iconst 0))))
(x64_shr $I32 (x64_not $I64 x) (Imm8Reg.Imm8 31)))
;; For XMM-held values, we lower to `PCMP*` instructions, sometimes more than
;; one. To note: what is different here about the output values is that each
;; lane will be filled with all 1s or all 0s according to the comparison,