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riscv64: remove valueregs_2_reg extractor. (#5426)

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This extractor had a side-effect of invoking `put_in_regs`, which is not
supposed to be invoked until the pattern-matching commits to evaluating
a rule right-hand side (i.e., cannot backtrack). In this case the
side-effect was mostly benign (in theory it could have caused additional
values to be computed needlessly), but in general we should be careful
to keep side-effects out of the left-hand side to enable further
optimizations and work on islec.

The implicit conversion from `Value` to `Reg` turns out to be enough to
make the rules in question work, so we can simply remove the use of the
extractor in this case.
This commit is contained in:
Chris Fallin
2022-12-13 11:47:20 -08:00
committed by GitHub
parent a76e0e8aa5
commit 92ce79366c
4 changed files with 44 additions and 53 deletions
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5
cranelift/codegen/src/isa/riscv64/inst.isle
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@@ -1366,11 +1366,6 @@
(load_imm12 x)
(alu_rr_imm12 (AluOPRRI.Addi) (zero_reg) (imm12_const x)))
;; Let me always get low part of ValueRegs.
;; Sometimes I only need lowest bits, like `I8 << I128`.
(decl valueregs_2_reg (Reg) Value)
(extern extractor infallible valueregs_2_reg valueregs_2_reg)
(decl lower_cls_i128 (ValueRegs) ValueRegs)
(rule
(lower_cls_i128 x)

58
cranelift/codegen/src/isa/riscv64/lower.isle
View File

@@ -298,93 +298,93 @@
(lower_popcnt_i128 x))
;;;; Rules for `ishl` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(rule 1 (lower (has_type $I8 (ishl x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Sllw) x (alu_andi y 7))
(rule 1 (lower (has_type $I8 (ishl x y)))
(alu_rrr (AluOPRRR.Sllw) x (alu_andi (value_regs_get y 0) 7))
)
(rule 2 (lower (has_type $I8 (ishl x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Slliw) x (imm12_and y 7)))
(rule 1 (lower (has_type $I16 (ishl x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Sllw) x (alu_andi y 15))
(rule 1 (lower (has_type $I16 (ishl x y)))
(alu_rrr (AluOPRRR.Sllw) x (alu_andi (value_regs_get y 0) 15))
)
(rule 2 (lower (has_type $I16 (ishl x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Slliw) x (imm12_and y 15)))
(rule 1 (lower (has_type $I32 (ishl x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Sllw) x y))
(rule 1 (lower (has_type $I32 (ishl x y)))
(alu_rrr (AluOPRRR.Sllw) x (value_regs_get y 0)))
(rule 2 (lower (has_type $I32 (ishl x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Slliw) x y))
(rule 2 (lower (has_type $I64 (ishl x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Slli) x y))
(rule 1 (lower (has_type $I64 (ishl x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Sll) x y))
(rule 1 (lower (has_type $I64 (ishl x y)))
(alu_rrr (AluOPRRR.Sll) x (value_regs_get y 0)))
(rule 0 (lower (has_type $I128 (ishl x y)))
(lower_i128_ishl x y))
;;;; Rules for `ushr` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(rule 1 (lower (has_type $I8 (ushr x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Srlw) (ext_int_if_need $false x $I8) (alu_andi y 7))
(rule 1 (lower (has_type $I8 (ushr x y)))
(alu_rrr (AluOPRRR.Srlw) (ext_int_if_need $false x $I8) (alu_andi (value_regs_get y 0) 7))
)
(rule 2 (lower (has_type $I8 (ushr x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.SrliW) (ext_int_if_need $false x $I8) (imm12_and y 7)))
(rule 1 (lower (has_type $I16 (ushr x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Srlw) (ext_int_if_need $false x $I16) (alu_andi y 15))
(rule 1 (lower (has_type $I16 (ushr x y)))
(alu_rrr (AluOPRRR.Srlw) (ext_int_if_need $false x $I16) (alu_andi (value_regs_get y 0) 15))
)
(rule 2 (lower (has_type $I16 (ushr x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.SrliW) (ext_int_if_need $false x $I16) (imm12_and y 15)))
(rule 1 (lower (has_type $I32 (ushr x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Srlw) x y))
(rule 1 (lower (has_type $I32 (ushr x y)))
(alu_rrr (AluOPRRR.Srlw) x (value_regs_get y 0)))
(rule 2 (lower (has_type $I32 (ushr x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.SrliW) x y))
(rule 2 (lower (has_type $I64 (ushr x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Srli) x y))
(rule 1 (lower (has_type $I64 (ushr x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Srl) x y))
(rule 1 (lower (has_type $I64 (ushr x y)))
(alu_rrr (AluOPRRR.Srl) x (value_regs_get y 0)))
(rule 0 (lower (has_type $I128 (ushr x y)))
(lower_i128_ushr x y))
;;;; Rules for `sshr` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(rule 1 (lower (has_type $I8 (sshr x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Sra) (ext_int_if_need $true x $I8) (alu_andi y 7))
(rule 1 (lower (has_type $I8 (sshr x y)))
(alu_rrr (AluOPRRR.Sra) (ext_int_if_need $true x $I8) (alu_andi (value_regs_get y 0) 7))
)
(rule 2 (lower (has_type $I8 (sshr x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Srai) (ext_int_if_need $true x $I8) (imm12_and y 7)))
(rule 1 (lower (has_type $I16 (sshr x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Sra) (ext_int_if_need $true x $I16) (alu_andi y 15))
(rule 1 (lower (has_type $I16 (sshr x y)))
(alu_rrr (AluOPRRR.Sra) (ext_int_if_need $true x $I16) (alu_andi (value_regs_get y 0) 15))
)
(rule 2 (lower (has_type $I16 (sshr x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Srai) (ext_int_if_need $true x $I16) (imm12_and y 15)))
(rule 1 (lower (has_type $I32 (sshr x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Sraw) x y))
(rule 1 (lower (has_type $I32 (sshr x y)))
(alu_rrr (AluOPRRR.Sraw) x (value_regs_get y 0)))
(rule 2 (lower (has_type $I32 (sshr x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Sraiw) x y))
(rule 1 (lower (has_type $I64 (sshr x (valueregs_2_reg y))))
(alu_rrr (AluOPRRR.Sra) x y))
(rule 1 (lower (has_type $I64 (sshr x y)))
(alu_rrr (AluOPRRR.Sra) x (value_regs_get y 0)))
(rule 2 (lower (has_type $I64 (sshr x (imm12_from_value y))))
(alu_rr_imm12 (AluOPRRI.Srai) x y))
(rule 0 (lower (has_type $I128 (sshr x y)))
(lower_i128_sshr x y))
(lower_i128_sshr x (value_regs_get y 0)))
;;;; Rules for `rotl` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(rule (lower (has_type (fits_in_64 ty) (rotl x (valueregs_2_reg y))))
(lower_rotl ty (ext_int_if_need $false x ty) y))
(rule (lower (has_type (fits_in_64 ty) (rotl x y)))
(lower_rotl ty (ext_int_if_need $false x ty) (value_regs_get y 0)))
(rule 1 (lower (has_type $I128 (rotl x y)))
(lower_i128_rotl x y))
;;;; Rules for `rotr` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(rule (lower (has_type (fits_in_64 ty) (rotr x (valueregs_2_reg y))))
(lower_rotr ty (ext_int_if_need $false x ty) y))
(rule (lower (has_type (fits_in_64 ty) (rotr x y)))
(lower_rotr ty (ext_int_if_need $false x ty) (value_regs_get y 0)))
(rule 1 (lower (has_type $I128 (rotr x y)))
(lower_i128_rotr x y))

4
cranelift/codegen/src/isa/riscv64/lower/isle.rs
View File

@@ -315,10 +315,6 @@ impl generated_code::Context for IsleContext<'_, '_, MInst, Flags, IsaFlags, 6>
self.isa_flags.has_zbkb()
}
fn valueregs_2_reg(&mut self, val: Value) -> Reg {
self.put_in_regs(val).regs()[0]
}
fn inst_output_get(&mut self, x: InstOutput, index: u8) -> ValueRegs {
x[index as usize]
}