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Merged
cfallin merged 5 commits into from
Mar 31, 2023
Merged

ISLE: move icmp rewrites to separate file. #6120

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9f4ed3b
ISLE: move `icmp` rewrites to separate file.
Kmeakin Mar 29, 2023
0b4836c
Put parameterized and unparameterized `icmp` tests in separate files
Kmeakin Mar 30, 2023
29f0425
Undo refactoring of (ir)reflexivity rewrites
Kmeakin Mar 30, 2023
3ca8551
Fix `icmp-parameterised.clif`
Kmeakin Mar 30, 2023
e7dae6c
Undo formatting/comment changes
Kmeakin Mar 30, 2023
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5 changes: 3 additions & 2 deletions cranelift/codegen/build.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -220,11 +220,12 @@ fn get_isle_compilations(
output: out_dir.join("isle_opt.rs"),
inputs: vec![
prelude_isle.clone(),
prelude_opt_isle.clone(),
prelude_opt_isle,
src_opts.join("algebraic.isle"),
src_opts.join("icmp.isle"),
src_opts.join("cprop.isle"),
],
untracked_inputs: vec![clif_opt_isle.clone()],
untracked_inputs: vec![clif_opt_isle],
},
// The x86-64 instruction selector.
IsleCompilation {
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191 changes: 0 additions & 191 deletions cranelift/codegen/src/opts/algebraic.isle
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Original file line number Diff line number Diff line change
Expand Up @@ -322,151 +322,11 @@
(rule (simplify x @ (f64const _ _))
(remat x))

;; Optimize icmp-of-icmp.
(rule (simplify (ne ty
(uextend _ inner @ (icmp ty _ _ _))
(iconst _ (u64_from_imm64 0))))
(subsume inner))

(rule (simplify (eq ty
(uextend _ (icmp ty cc x y))
(iconst _ (u64_from_imm64 0))))
(subsume (icmp ty (intcc_inverse cc) x y)))

;; Optimize select-of-uextend-of-icmp to select-of-icmp, because
;; select can take an I8 condition too.
(rule (simplify
(select ty (uextend _ c @ (icmp _ _ _ _)) x y))
(select ty c x y))
(rule (simplify
(select ty (uextend _ c @ (icmp _ _ _ _)) x y))
(select ty c x y))

;; `x == x` is always true for integers; `x != x` is false. Strict
;; inequalities are false, and loose inequalities are true.
(rule (simplify (eq (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 1)))
(rule (simplify (ne (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 0)))
(rule (simplify (ugt (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 0)))
(rule (simplify (uge (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 1)))
(rule (simplify (sgt (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 0)))
(rule (simplify (sge (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 1)))
(rule (simplify (ult (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 0)))
(rule (simplify (ule (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 1)))
(rule (simplify (slt (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 0)))
(rule (simplify (sle (fits_in_64 (ty_int ty)) x x)) (iconst ty (imm64 1)))

;; (x ^ -1) can be replaced with the `bnot` instruction
(rule (simplify (bxor ty x (iconst ty k)))
(if-let -1 (i64_sextend_imm64 ty k))
(bnot ty x))


;; Masking the result of a comparison with 1 always results in the comparison
;; itself. Note that comparisons in wasm may sometimes be hidden behind
;; extensions.
(rule (simplify
(band (ty_int _)
cmp @ (icmp _ _ _ _)
(iconst _ (u64_from_imm64 1))))
cmp)
(rule (simplify
(band (ty_int _)
extend @ (uextend _ (icmp _ _ _ _))
(iconst _ (u64_from_imm64 1))))
extend)

;; ult(x, 0) == false.
(rule (simplify
(ult (fits_in_64 (ty_int bty)) x zero @ (iconst _ (u64_from_imm64 0))))
(subsume (iconst bty (imm64 0))))

;; ule(x, 0) == eq(x, 0)
(rule (simplify
(ule (fits_in_64 (ty_int bty)) x zero @ (iconst _ (u64_from_imm64 0))))
(eq bty x zero))

;; ugt(x, 0) == ne(x, 0).
(rule (simplify
(ugt (fits_in_64 (ty_int bty)) x zero @ (iconst _ (u64_from_imm64 0))))
(ne bty x zero))

;; uge(x, 0) == true.
(rule (simplify
(uge (fits_in_64 (ty_int bty)) x zero @ (iconst _ (u64_from_imm64 0))))
(subsume (iconst bty (imm64 1))))

;; ult(x, UMAX) == ne(x, UMAX).
(rule (simplify
(ult (fits_in_64 (ty_int bty)) x umax @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_umax cty)))
(ne bty x umax))

;; ule(x, UMAX) == true.
(rule (simplify
(ule (fits_in_64 (ty_int bty)) x umax @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_umax cty)))
(subsume (iconst bty (imm64 1))))

;; ugt(x, UMAX) == false.
(rule (simplify
(ugt (fits_in_64 (ty_int bty)) x umax @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_umax cty)))
(subsume (iconst bty (imm64 0))))

;; uge(x, UMAX) == eq(x, UMAX).
(rule (simplify
(uge (fits_in_64 (ty_int bty)) x umax @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_umax cty)))
(eq bty x umax))

;; slt(x, SMIN) == false.
(rule (simplify
(slt (fits_in_64 (ty_int bty)) x smin @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_smin cty)))
(subsume (iconst bty (imm64 0))))

;; sle(x, SMIN) == eq(x, SMIN).
(rule (simplify
(sle (fits_in_64 (ty_int bty)) x smin @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_smin cty)))
(eq bty x smin))

;; sgt(x, SMIN) == ne(x, SMIN).
(rule (simplify
(sgt (fits_in_64 (ty_int bty)) x smin @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_smin cty)))
(ne bty x smin))

;; sge(x, SMIN) == true.
(rule (simplify
(sge (fits_in_64 (ty_int bty)) x smin @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_smin cty)))
(subsume (iconst bty (imm64 1))))

;; slt(x, SMAX) == ne(x, SMAX).
(rule (simplify
(slt (fits_in_64 (ty_int bty)) x smax @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_smax cty)))
(ne bty x smax))

;; sle(x, SMAX) == true.
(rule (simplify
(sle (fits_in_64 (ty_int bty)) x smax @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_smax cty)))
(subsume (iconst bty (imm64 1))))

;; sgt(x, SMAX) == false.
(rule (simplify
(sgt (fits_in_64 (ty_int bty)) x smax @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_smax cty)))
(subsume (iconst bty (imm64 0))))

;; sge(x, SMAX) == eq(x, SMAX).
(rule (simplify
(sge (fits_in_64 (ty_int bty)) x smax @ (iconst cty (u64_from_imm64 y))))
(if-let $true (u64_eq y (ty_smax cty)))
(eq bty x smax))

;; 32-bit integers zero-extended to 64-bit integers are never negative
(rule (simplify
(slt ty
Expand All @@ -479,57 +339,6 @@
(iconst _ (u64_from_imm64 0))))
(iconst ty (imm64 1)))

(decl pure decompose_intcc (IntCC) u64)
(rule (decompose_intcc (IntCC.Equal)) 1)
(rule (decompose_intcc (IntCC.UnsignedLessThan)) 2)
(rule (decompose_intcc (IntCC.SignedLessThan)) 2)
(rule (decompose_intcc (IntCC.UnsignedLessThanOrEqual)) 3)
(rule (decompose_intcc (IntCC.SignedLessThanOrEqual)) 3)
(rule (decompose_intcc (IntCC.UnsignedGreaterThan)) 4)
(rule (decompose_intcc (IntCC.SignedGreaterThan)) 4)
(rule (decompose_intcc (IntCC.UnsignedGreaterThanOrEqual)) 5)
(rule (decompose_intcc (IntCC.SignedGreaterThanOrEqual)) 5)
(rule (decompose_intcc (IntCC.NotEqual)) 6)

(decl compose_icmp (Type u64 bool Value Value) Value)
(rule (compose_icmp ty 0 _ _ _) (subsume (iconst ty (imm64 0))))
(rule (compose_icmp ty 1 _ x y) (icmp ty (IntCC.Equal) x y))
(rule (compose_icmp ty 2 $false x y) (icmp ty (IntCC.UnsignedLessThan) x y))
(rule (compose_icmp ty 2 $true x y) (icmp ty (IntCC.SignedLessThan) x y))
(rule (compose_icmp ty 3 $false x y) (icmp ty (IntCC.UnsignedLessThanOrEqual) x y))
(rule (compose_icmp ty 3 $true x y) (icmp ty (IntCC.SignedLessThanOrEqual) x y))
(rule (compose_icmp ty 4 $false x y) (icmp ty (IntCC.UnsignedGreaterThan) x y))
(rule (compose_icmp ty 4 $true x y) (icmp ty (IntCC.SignedGreaterThan) x y))
(rule (compose_icmp ty 5 $false x y) (icmp ty (IntCC.UnsignedGreaterThanOrEqual) x y))
(rule (compose_icmp ty 5 $true x y) (icmp ty (IntCC.SignedGreaterThanOrEqual) x y))
(rule (compose_icmp ty 6 _ x y) (icmp ty (IntCC.NotEqual) x y))
(rule (compose_icmp ty 7 _ _ _) (subsume (iconst ty (imm64 1))))

(decl pure intcc_class (IntCC) u64)
(rule (intcc_class (IntCC.UnsignedLessThan)) 1)
(rule (intcc_class (IntCC.UnsignedLessThanOrEqual)) 1)
(rule (intcc_class (IntCC.UnsignedGreaterThan)) 1)
(rule (intcc_class (IntCC.UnsignedGreaterThanOrEqual)) 1)
(rule (intcc_class (IntCC.SignedLessThan)) 2)
(rule (intcc_class (IntCC.SignedLessThanOrEqual)) 2)
(rule (intcc_class (IntCC.SignedGreaterThan)) 2)
(rule (intcc_class (IntCC.SignedGreaterThanOrEqual)) 2)
(rule (intcc_class (IntCC.Equal)) 3)
(rule (intcc_class (IntCC.NotEqual)) 3)

(decl pure partial intcc_comparable (IntCC IntCC) bool)
(rule (intcc_comparable x y)
(if-let (u64_nonzero class) (u64_and (intcc_class x) (intcc_class y)))
(u64_eq 2 class))

(rule (simplify (band ty (icmp ty cc1 x y) (icmp ty cc2 x y)))
(if-let signed (intcc_comparable cc1 cc2))
(compose_icmp ty (u64_and (decompose_intcc cc1) (decompose_intcc cc2)) signed x y))

(rule (simplify (bor ty (icmp ty cc1 x y) (icmp ty cc2 x y)))
(if-let signed (intcc_comparable cc1 cc2))
(compose_icmp ty (u64_or (decompose_intcc cc1) (decompose_intcc cc2)) signed x y))

;; Transform select-of-icmp into {u,s}{min,max} instructions where possible.
(rule (simplify (select ty (sgt _ x y) x y)) (smax ty x y))
(rule (simplify (select ty (sge _ x y) x y)) (smax ty x y))
Expand Down
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