;; Constant propagation.
(rule (simplify
(iadd (fits_in_64 ty)
(iconst ty (u64_from_imm64 k1))
(iconst ty (u64_from_imm64 k2))))
(subsume (iconst ty (imm64_masked ty (u64_add k1 k2)))))
(rule (simplify
(isub (fits_in_64 ty)
(iconst ty (u64_from_imm64 k1))
(iconst ty (u64_from_imm64 k2))))
(subsume (iconst ty (imm64_masked ty (u64_sub k1 k2)))))
(rule (simplify
(imul (fits_in_64 ty)
(iconst ty (u64_from_imm64 k1))
(iconst ty (u64_from_imm64 k2))))
(subsume (iconst ty (imm64_masked ty (u64_mul k1 k2)))))
(rule (simplify
(sdiv (fits_in_64 ty)
(iconst ty (u64_from_imm64 k1))
(iconst ty (u64_from_imm64 k2))))
(if-let d (u64_sdiv k1 k2))
(subsume (iconst ty (imm64_masked ty d))))
(rule (simplify
(udiv (fits_in_64 ty)
(iconst ty (u64_from_imm64 k1))
(iconst ty (u64_from_imm64 k2))))
(if-let d (u64_udiv k1 k2))
(subsume (iconst ty (imm64_masked ty d))))
(rule (simplify
(bor (fits_in_64 ty)
(iconst ty (u64_from_imm64 k1))
(iconst ty (u64_from_imm64 k2))))
(subsume (iconst ty (imm64_masked ty (u64_or k1 k2)))))
(rule (simplify
(band (fits_in_64 ty)
(iconst ty (u64_from_imm64 k1))
(iconst ty (u64_from_imm64 k2))))
(subsume (iconst ty (imm64_masked ty (u64_and k1 k2)))))
(rule (simplify
(bxor (fits_in_64 ty)
(iconst ty (u64_from_imm64 k1))
(iconst ty (u64_from_imm64 k2))))
(subsume (iconst ty (imm64_masked ty (u64_xor k1 k2)))))
(rule (simplify
(bnot (fits_in_64 ty)
(iconst ty (u64_from_imm64 k))))
(subsume (iconst ty (imm64_masked ty (u64_not k)))))
(rule (simplify (ishl (fits_in_64 ty)
(iconst ty k1)
(iconst _ k2)))
(subsume (iconst ty (imm64_shl ty k1 k2))))
(rule (simplify (ushr (fits_in_64 ty)
(iconst ty k1)
(iconst _ k2)))
(subsume (iconst ty (imm64_ushr ty k1 k2))))
(rule (simplify (sshr (fits_in_64 ty)
(iconst ty k1)
(iconst _ k2)))
(subsume (iconst ty (imm64_sshr ty k1 k2))))
(rule (simplify (ireduce narrow (iconst (fits_in_64 _) (u64_from_imm64 imm))))
(subsume (iconst narrow (imm64_masked narrow imm))))
;; iconst_[su] support $I128, but do so by extending, so restricting to
;; 64-bit or smaller keeps it from just remaking essentially the same thing.
(rule (simplify (uextend (fits_in_64 wide) (iconst_u narrow k)))
(subsume (iconst_u wide k)))
(rule (simplify (sextend (fits_in_64 wide) (iconst_s narrow k)))
(subsume (iconst_s wide k)))
(rule (simplify
(icmp result_ty
cc
(iconst ty k1)
(iconst ty k2)))
(subsume (iconst result_ty (imm64_icmp ty cc k1 k2))))
;; Canonicalize via commutativity: push immediates to the right.
;;
;; (op k x) --> (op x k)
(rule (simplify
(iadd ty k @ (iconst ty _) x))
(iadd ty x k))
;; sub is not commutative, but we can flip the args and negate the
;; whole thing.
(rule (simplify
(isub ty k @ (iconst ty _) x))
(ineg ty (isub ty x k)))
(rule (simplify
(imul ty k @ (iconst ty _) x))
(imul ty x k))
(rule (simplify
(bor ty k @ (iconst ty _) x))
(bor ty x k))
(rule (simplify
(band ty k @ (iconst ty _) x))
(band ty x k))
(rule (simplify
(bxor ty k @ (iconst ty _) x))
(bxor ty x k))
(rule (simplify
(icmp ty cc k @ (iconst _ _) x))
(icmp ty (intcc_swap_args cc) x k))
;; Canonicalize via associativity: reassociate to a right-heavy tree
;; for constants.
;;
;; (op (op x k) k) --> (op x (op k k))
(rule (simplify
(iadd ty (iadd ty x k1 @ (iconst ty _)) k2 @ (iconst ty _)))
(iadd ty x (iadd ty k1 k2)))
;; sub is not directly associative, but we can flip a sub to an add to
;; make it work:
;; - (sub (sub x k1) k2) -> (sub x (add k1 k2))
;; - (sub (sub k1 x) k2) -> (sub (sub k1 k2) x)
;; - (sub (add x k1) k2) -> (sub x (sub k2 k1))
;; - (add (sub x k1) k2) -> (add x (sub k2 k1))
;; - (add (sub k1 x) k2) -> (sub (add k1 k2) x)
(rule (simplify (isub ty
(isub ty x (iconst ty (u64_from_imm64 k1)))
(iconst ty (u64_from_imm64 k2))))
(isub ty x (iconst ty (imm64_masked ty (u64_add k1 k2)))))
(rule (simplify (isub ty
(isub ty (iconst ty (u64_from_imm64 k1)) x)
(iconst ty (u64_from_imm64 k2))))
(isub ty (iconst ty (imm64_masked ty (u64_sub k1 k2))) x))
(rule (simplify (isub ty
(iadd ty x (iconst ty (u64_from_imm64 k1)))
(iconst ty (u64_from_imm64 k2))))
(isub ty x (iconst ty (imm64_masked ty (u64_sub k2 k1)))))
(rule (simplify (iadd ty
(isub ty x (iconst ty (u64_from_imm64 k1)))
(iconst ty (u64_from_imm64 k2))))
(iadd ty x (iconst ty (imm64_masked ty (u64_sub k2 k1)))))
(rule (simplify (iadd ty
(isub ty (iconst ty (u64_from_imm64 k1)) x)
(iconst ty (u64_from_imm64 k2))))
(isub ty (iconst ty (imm64_masked ty (u64_add k1 k2))) x))
(rule (simplify
(imul ty (imul ty x k1 @ (iconst ty _)) k2 @ (iconst ty _)))
(imul ty x (imul ty k1 k2)))
(rule (simplify
(bor ty (bor ty x k1 @ (iconst ty _)) k2 @ (iconst ty _)))
(bor ty x (bor ty k1 k2)))
(rule (simplify
(band ty (band ty x k1 @ (iconst ty _)) k2 @ (iconst ty _)))
(band ty x (band ty k1 k2)))
(rule (simplify
(bxor ty (bxor ty x k1 @ (iconst ty _)) k2 @ (iconst ty _)))
(bxor ty x (bxor ty k1 k2)))
(rule (simplify (select ty (iconst_u _ (u64_nonzero _)) x _))
(subsume x))
(rule (simplify (select ty (iconst_u _ 0) _ y))
(subsume y))
;; Replace subtraction by a "negative" constant with addition.
;; Notably, this gives `x - (-1) == x + 1`, so other patterns don't have to
;; match the subtract-negative-one version too.
;; TODO: it would be nice to do this for `x + (-1) == x - 1` as well, but
;; that needs work in lowering first to avoid regressing addressing modes.
(rule (simplify (isub ty x (iconst_s ty k)))
(if-let $true (u64_lt (i64_as_u64 (i64_neg k)) (i64_as_u64 k)))
(iadd ty x (iconst ty (imm64_masked ty (i64_as_u64 (i64_neg k))))))
;; TODO: fadd, fsub, fmul, fdiv, fneg, fabs
;; A splat of a constant can become a direct `vconst` with the appropriate bit
;; pattern.
(rule (simplify (splat dst (iconst $I8 n)))
(vconst dst (splat8 (u64_uextend_imm64 $I8 n))))
(rule (simplify (splat dst (iconst $I16 n)))
(vconst dst (splat16 (u64_uextend_imm64 $I16 n))))
(rule (simplify (splat dst (iconst $I32 n)))
(vconst dst (splat32 (u64_uextend_imm64 $I32 n))))
(rule (simplify (splat dst (iconst $I64 n)))
(vconst dst (splat64 (u64_uextend_imm64 $I64 n))))
(rule (simplify (splat dst (f32const _ (u32_from_ieee32 n))))
(vconst dst (splat32 n)))
(rule (simplify (splat dst (f64const _ (u64_from_ieee64 n))))
(vconst dst (splat64 n)))
(decl splat8 (u64) Constant)
(rule (splat8 n) (splat16 (u64_or n (u64_shl n 8))))
(decl splat16 (u64) Constant)
(rule (splat16 n) (splat32 (u64_or n (u64_shl n 16))))
(decl splat32 (u64) Constant)
(rule (splat32 n) (splat64 (u64_or n (u64_shl n 32))))
(decl splat64 (u64) Constant)
(extern constructor splat64 splat64)
;; Reassociate nested shifts of constants to put constants together for cprop.
;;
;; ((A shift b) shift C) ==> ((A shift C) shift b)
(rule (simplify (ishl ty (ishl ty a@(iconst _ _) b) c@(iconst _ _)))
(ishl ty (ishl ty a c) b))
(rule (simplify (ushr ty (ushr ty a@(iconst _ _) b) c@(iconst _ _)))
(ushr ty (ushr ty a c) b))
(rule (simplify (sshr ty (sshr ty a@(iconst _ _) b) c@(iconst _ _)))
(sshr ty (sshr ty a c) b))
;; When we operations that are both commutative and associative, reassociate
;; constants together for cprop:
;;
;; ((a op B) op (c op D)) ==> ((a op c) op (B op D))
;;
;; Where `op` is one of: `iadd`, `imul`, `band`, `bor`, or `bxor`.
(rule (simplify (iadd ty
(iadd ty a b@(iconst _ _))
(iadd ty c d@(iconst _ _))))
(iadd ty (iadd ty a c) (iadd ty b d)))
(rule (simplify (imul ty
(imul ty a b@(iconst _ _))
(imul ty c d@(iconst _ _))))
(imul ty (imul ty a c) (imul ty b d)))
(rule (simplify (band ty
(band ty a b@(iconst _ _))
(band ty c d@(iconst _ _))))
(band ty (band ty a c) (band ty b d)))
(rule (simplify (bor ty
(bor ty a b@(iconst _ _))
(bor ty c d@(iconst _ _))))
(bor ty (bor ty a c) (bor ty b d)))
(rule (simplify (bxor ty
(bxor ty a b@(iconst _ _))
(bxor ty c d@(iconst _ _))))
(bxor ty (bxor ty a c) (bxor ty b d)))