vendor/cranelift-codegen/src/opts/cprop.isle

;; 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)))))

;; 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))

;; 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 _ (u64_from_imm64 (u64_nonzero _))) x y))
      x)
(rule (simplify
       (select ty (iconst _ (u64_from_imm64 0)) x y))
      y)

;; TODO: fadd, fsub, fmul, fdiv, fneg, fabs