Path: blob/main/cranelift/codegen/src/prelude_opt.isle
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;; Prelude definitions specific to the mid-end.
;; Any `extern` definitions here are generally implemented in `src/opts.rs`.
;;;;; eclass and enode access ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Extract any node(s) for the given eclass ID.
(decl multi inst_data_value (Type InstructionData) Value)
(extern extractor inst_data_value inst_data_value_etor)
;; An extractor from an `Inst` to its `InstructionData`.
(decl inst_data (InstructionData) Inst)
(extern extractor inst_data inst_data_etor)
;; Identical to `inst_data_value`, just with a different ISLE type. This is
;; basically a manual version of `curry`/`uncurry` in Haskell: to compose
;; extractors the outer one needs to be single-parameter, so this combines the
;; two parameters of `inst_data_value` into one.
(type TypeAndInstructionData (primitive TypeAndInstructionData))
(decl multi inst_data_value_tupled (TypeAndInstructionData) Value)
(extern extractor inst_data_value_tupled inst_data_value_tupled_etor)
;; Construct a pure node, returning a new (or deduplicated
;; already-existing) eclass ID.
(decl make_inst (Type InstructionData) Value)
(extern constructor make_inst make_inst_ctor)
;; Make a new side-effectful instruction, do not insert it into the layout, and
;; return its `Inst`.
(decl make_skeleton_inst (InstructionData) Inst)
(extern constructor make_skeleton_inst make_skeleton_inst_ctor)
;; Constructors for value arrays.
(decl value_array_2_ctor (Value Value) ValueArray2)
(extern constructor value_array_2_ctor value_array_2_ctor)
(decl value_array_3_ctor (Value Value Value) ValueArray3)
(extern constructor value_array_3_ctor value_array_3_ctor)
(rule (eq ty x y) (icmp ty (IntCC.Equal) x y))
(rule (ne ty x y) (icmp ty (IntCC.NotEqual) x y))
(rule (ult ty x y) (icmp ty (IntCC.UnsignedLessThan) x y))
(rule (ule ty x y) (icmp ty (IntCC.UnsignedLessThanOrEqual) x y))
(rule (ugt ty x y) (icmp ty (IntCC.UnsignedGreaterThan) x y))
(rule (uge ty x y) (icmp ty (IntCC.UnsignedGreaterThanOrEqual) x y))
(rule (slt ty x y) (icmp ty (IntCC.SignedLessThan) x y))
(rule (sle ty x y) (icmp ty (IntCC.SignedLessThanOrEqual) x y))
(rule (sgt ty x y) (icmp ty (IntCC.SignedGreaterThan) x y))
(rule (sge ty x y) (icmp ty (IntCC.SignedGreaterThanOrEqual) x y))
;; 3-way comparison, returning -1/0/+1 in I8
(decl spaceship_s (Type Value Value) Value)
(rule (spaceship_s ty x y) (isub $I8 (sgt ty x y) (slt ty x y)))
(extractor (spaceship_s ty x y) (isub $I8 (sgt ty x y) (slt ty x y)))
(decl spaceship_u (Type Value Value) Value)
(rule (spaceship_u ty x y) (isub $I8 (ugt ty x y) (ult ty x y)))
(extractor (spaceship_u ty x y) (isub $I8 (ugt ty x y) (ult ty x y)))
;;;;; optimization toplevel ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; The main matcher rule invoked by the toplevel driver.
(decl multi simplify (Value) Value)
;; The kind of simplification to perform on a skeleton instruction.
(type SkeletonInstSimplification
(enum
;; Remove the instruction being simplified from the skeleton, it is
;; unnecessary.
;;
;; The instruction must not define any results.
(Remove)
;; Remove the instruction being simplified from the skeleton, and
;; replace its result value with the given `val`.
(RemoveWithVal (val Value))
;; Replace the instruction being simplified with the given instruction.
;;
;; The given instruction must not already be in a block and must define
;; the same number and types of results as the old instruction that it
;; is replacing.
(Replace (inst Inst))
;; Like `Replace` but replace the old instruction's result value with
;; the given `val`.
;;
;; The old instruction must define a single result value and `val` must
;; match its type. The new instruction need not define the same number
;; or types of results as the old instruction.
(ReplaceWithVal (inst Inst) (val Value))))
(decl pure inst_to_skeleton_inst_simplification (Inst) SkeletonInstSimplification)
(rule (inst_to_skeleton_inst_simplification inst)
(SkeletonInstSimplification.Replace inst))
(decl pure value_to_skeleton_inst_simplification (Value) SkeletonInstSimplification)
(rule (value_to_skeleton_inst_simplification val)
(SkeletonInstSimplification.RemoveWithVal val))
(decl pure remove_inst () SkeletonInstSimplification)
(rule (remove_inst) (SkeletonInstSimplification.Remove))
(decl pure replace_with_val (Inst Value) SkeletonInstSimplification)
(rule (replace_with_val inst val) (SkeletonInstSimplification.ReplaceWithVal inst val))
(convert Inst SkeletonInstSimplification inst_to_skeleton_inst_simplification)
(convert Value SkeletonInstSimplification value_to_skeleton_inst_simplification)
;; The main term for simplifying side-effectful instructions, invoked by the
;; egraph driver.
(decl multi simplify_skeleton (Inst) SkeletonInstSimplification)
;; Mark a node as requiring remat when used in a different block.
(decl remat (Value) Value)
(extern constructor remat remat)
;; Mark a node as subsuming whatever else it's rewritten from -- this
;; is definitely preferable, not just a possible option. Useful for,
;; e.g., constant propagation where we arrive at a definite "final
;; answer".
(decl subsume (Value) Value)
(extern constructor subsume subsume)
;;;;; constructors ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(decl iconst_sextend_etor (Type i64) TypeAndInstructionData)
(extern extractor iconst_sextend_etor iconst_sextend_etor)
;; Construct an `iconst` from an `i64` or Extract an `i64` from an `iconst`
;; by treating the constant as signed.
;; When extracting, smaller types get their value sign-extended to 64-bits,
;; so that `iconst.i8 255` will give you a `-1_i64`.
;; When constructing, the rule will fail if the value cannot be represented in
;; the target type. If it fits, it'll be masked accordingly in the constant.
(decl iconst_s (Type i64) Value)
(extractor (iconst_s ty c) (inst_data_value_tupled (iconst_sextend_etor ty c)))
(rule 0 (iconst_s ty c)
(if-let c_masked (u64_and (i64_cast_unsigned c)
(ty_umax ty)))
(if-let c_reextended (i64_sextend_u64 ty c_masked))
(if-let true (i64_eq c c_reextended))
(iconst ty (imm64 c_masked)))
(rule 1 (iconst_s $I128 c) (sextend $I128 (iconst_s $I64 c)))
;; Construct an `iconst` from a `u64` or Extract a `u64` from an `iconst`
;; by treating the constant as unsigned.
;; When extracting, smaller types get their value zero-extended to 64-bits,
;; so that `iconst.i8 255` will give you a `255_u64`.
;; When constructing, the rule will fail if the value cannot be represented in
;; the target type.
(decl iconst_u (Type u64) Value)
(extractor (iconst_u ty c) (iconst ty (u64_from_imm64 c)))
(rule 0 (iconst_u ty c)
(if-let true (u64_lt_eq c (ty_umax ty)))
(iconst ty (imm64 c)))
(rule 1 (iconst_u $I128 c) (uextend $I128 (iconst_u $I64 c)))
;; These take `Value`, rather than going through `inst_data_value_tupled`,
;; because most of the time they want to return the original `Value`, and it
;; would be a waste to need to re-GVN the instruction data in those cases.
(decl multi sextend_maybe_etor (Type Value) Value)
(extern extractor infallible sextend_maybe_etor sextend_maybe_etor)
(decl multi uextend_maybe_etor (Type Value) Value)
(extern extractor infallible uextend_maybe_etor uextend_maybe_etor)
;; Match or Construct a possibly-`uextend`ed value.
;; Gives the extended-to type and inner value when matching something that was
;; extended, or the input value and its type when the value isn't an extension.
;; Useful to write a single pattern that can match things that may or may not
;; have undergone C's "usual arithmetic conversions".
;; When generating values, extending to the same type is invalid CLIF,
;; so this avoids doing that where there's no extension actually needed.
(decl uextend_maybe (Type Value) Value)
(extractor (uextend_maybe ty val) (uextend_maybe_etor ty val))
(rule 0 (uextend_maybe ty val) (uextend ty val))
(rule 1 (uextend_maybe ty val@(value_type ty)) val)
;; Same as `uextend_maybe` above, just for `sextend`.
(decl sextend_maybe (Type Value) Value)
(extractor (sextend_maybe ty val) (sextend_maybe_etor ty val))
(rule 0 (sextend_maybe ty val) (sextend ty val))
(rule 1 (sextend_maybe ty val@(value_type ty)) val)
;;;;;; Helper CLIF Extractors ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(decl eq (Type Value Value) Value)
(extractor (eq ty x y) (icmp ty (IntCC.Equal) x y))
(decl ne (Type Value Value) Value)
(extractor (ne ty x y) (icmp ty (IntCC.NotEqual) x y))
(decl ult (Type Value Value) Value)
(extractor (ult ty x y) (icmp ty (IntCC.UnsignedLessThan) x y))
(decl ule (Type Value Value) Value)
(extractor (ule ty x y) (icmp ty (IntCC.UnsignedLessThanOrEqual) x y))
(decl ugt (Type Value Value) Value)
(extractor (ugt ty x y) (icmp ty (IntCC.UnsignedGreaterThan) x y))
(decl uge (Type Value Value) Value)
(extractor (uge ty x y) (icmp ty (IntCC.UnsignedGreaterThanOrEqual) x y))
(decl slt (Type Value Value) Value)
(extractor (slt ty x y) (icmp ty (IntCC.SignedLessThan) x y))
(decl sle (Type Value Value) Value)
(extractor (sle ty x y) (icmp ty (IntCC.SignedLessThanOrEqual) x y))
(decl sgt (Type Value Value) Value)
(extractor (sgt ty x y) (icmp ty (IntCC.SignedGreaterThan) x y))
(decl sge (Type Value Value) Value)
(extractor (sge ty x y) (icmp ty (IntCC.SignedGreaterThanOrEqual) x y))
;;;;;; Divison-By-Constant Helpers ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(decl pure i64_is_negative_power_of_two (i64) bool)
(rule (i64_is_negative_power_of_two x)
(u64_is_power_of_two (i64_cast_unsigned (i64_wrapping_neg x))))
(decl pure i64_is_any_sign_power_of_two (i64) bool)
(rule 2 (i64_is_any_sign_power_of_two x)
(if-let true (u64_is_power_of_two (i64_cast_unsigned x)))
true)
(rule 1 (i64_is_any_sign_power_of_two x)
(if-let true (i64_is_negative_power_of_two x))
true)
(rule 0 (i64_is_any_sign_power_of_two _) false)
(type DivConstMagicU32 (enum (U32 (mul_by u32)
(do_add bool)
(shift_by u32))))
(type DivConstMagicU64 (enum (U64 (mul_by u64)
(do_add bool)
(shift_by u32))))
(type DivConstMagicS32 (enum (S32 (mul_by i32)
(shift_by u32))))
(type DivConstMagicS64 (enum (S64 (mul_by i64)
(shift_by u32))))
;; Extern magic-const constructors and accessors.
(decl div_const_magic_u32 (u32) DivConstMagicU32)
(extern constructor div_const_magic_u32 div_const_magic_u32)
(decl div_const_magic_u64 (u64) DivConstMagicU64)
(extern constructor div_const_magic_u64 div_const_magic_u64)
(decl div_const_magic_s32 (i32) DivConstMagicS32)
(extern constructor div_const_magic_s32 div_const_magic_s32)
(decl div_const_magic_s64 (i64) DivConstMagicS64)
(extern constructor div_const_magic_s64 div_const_magic_s64)
;; Applying div-const magic for u32.
(decl apply_div_const_magic_u32 (Opcode Value u32) Value)
(rule (apply_div_const_magic_u32 opcode numerator divisor)
(apply_div_const_magic_u32_inner opcode numerator divisor (div_const_magic_u32 divisor)))
;; q0 = umuli numerator, mul_by
(decl apply_div_const_magic_u32_inner (Opcode Value u32 DivConstMagicU32) Value)
(rule (apply_div_const_magic_u32_inner opcode
numerator
divisor
magic @ (DivConstMagicU32.U32 mul_by _do_add _shift_by))
(let ((q0 Value (umulhi $I32 numerator (iconst_u $I32 mul_by))))
(apply_div_const_magic_u32_maybe_add opcode numerator divisor magic q0)))
;; qf = if do_add {
;; q1 = isub numerator, q0
;; q2 = ushr q1, 1
;; q3 = iadd q0, q2
;; maybe_shift(q3)
;; } else {
;; ushr q0, shift_by
;; };
(decl apply_div_const_magic_u32_maybe_add (Opcode Value u32 DivConstMagicU32 Value) Value)
(rule (apply_div_const_magic_u32_maybe_add opcode
numerator
divisor
magic @ (DivConstMagicU32.U32 _mul_by true _shift_by)
q0)
(let ((q1 Value (isub $I32 numerator q0))
(q2 Value (ushr $I32 q1 (iconst_u $I32 1)))
(q3 Value (iadd $I32 q0 q2)))
(apply_div_const_magic_u32_maybe_shift opcode numerator divisor magic q3)))
(rule (apply_div_const_magic_u32_maybe_add opcode
numerator
divisor
magic @ (DivConstMagicU32.U32 _mul_by false shift_by)
q0)
(let ((q3 Value (ushr $I32 q0 (iconst_u $I32 shift_by))))
(apply_div_const_magic_u32_finish opcode numerator divisor q3)))
;; qf = if shift_by == 0 {
;; q3
;; } else {
;; ushr q3, shift_by - 1
;; };
(decl apply_div_const_magic_u32_maybe_shift (Opcode Value u32 DivConstMagicU32 Value) Value)
(rule 2 (apply_div_const_magic_u32_maybe_shift opcode
numerator
divisor
(DivConstMagicU32.U32 _mul_by _do_add 0)
q3)
(apply_div_const_magic_u32_finish opcode numerator divisor q3))
(rule 1 (apply_div_const_magic_u32_maybe_shift opcode
numerator
divisor
(DivConstMagicU32.U32 _mul_by
_do_add
(u32_extract_non_zero shift_by))
q3)
(let ((qf Value (ushr $I32 q3 (iconst_u $I32 (u32_sub shift_by 1)))))
(apply_div_const_magic_u32_finish opcode numerator divisor qf)))
;; Now `qf` holds the final quotient. If necessary calculate the remainder
;; instead.
;;
;; if Opcode == Urem {
;; tt = imul qf, divisor
;; isub numerator, tt
;; } else {
;; qf
;; }
(decl apply_div_const_magic_u32_finish (Opcode Value u32 Value) Value)
(rule (apply_div_const_magic_u32_finish (Opcode.Udiv) _ _ qf) qf)
(rule (apply_div_const_magic_u32_finish (Opcode.Urem) numerator divisor qf)
(let ((tt Value (imul $I32 qf (iconst_u $I32 divisor))))
(isub $I32 numerator tt)))
;; Applying div-const magic for u64.
(decl apply_div_const_magic_u64 (Opcode Value u64) Value)
(rule (apply_div_const_magic_u64 opcode numerator divisor)
(apply_div_const_magic_u64_inner opcode numerator divisor (div_const_magic_u64 divisor)))
;; q0 = umuli numerator, mul_by
(decl apply_div_const_magic_u64_inner (Opcode Value u64 DivConstMagicU64) Value)
(rule (apply_div_const_magic_u64_inner opcode
numerator
divisor
magic @ (DivConstMagicU64.U64 mul_by _do_add _shift_by))
(let ((q0 Value (umulhi $I64 numerator (iconst_u $I64 mul_by))))
(apply_div_const_magic_u64_maybe_add opcode numerator divisor magic q0)))
;; qf = if do_add {
;; q1 = isub numerator, q0
;; q2 = ushr q1, 1
;; q3 = iadd q0, q2
;; maybe_shift(q3)
;; } else {
;; ushr q0, shift_by
;; };
(decl apply_div_const_magic_u64_maybe_add (Opcode Value u64 DivConstMagicU64 Value) Value)
(rule (apply_div_const_magic_u64_maybe_add opcode
numerator
divisor
magic @ (DivConstMagicU64.U64 _mul_by true _shift_by)
q0)
(let ((q1 Value (isub $I64 numerator q0))
(q2 Value (ushr $I64 q1 (iconst_u $I64 1)))
(q3 Value (iadd $I64 q0 q2)))
(apply_div_const_magic_u64_maybe_shift opcode numerator divisor magic q3)))
(rule (apply_div_const_magic_u64_maybe_add opcode
numerator
divisor
magic @ (DivConstMagicU64.U64 _mul_by false shift_by)
q0)
(let ((q3 Value (ushr $I64 q0 (iconst_u $I64 shift_by))))
(apply_div_const_magic_u64_finish opcode numerator divisor q3)))
;; qf = if shift_by == 0 {
;; q3
;; } else {
;; ushr q3, shift_by - 1
;; };
(decl apply_div_const_magic_u64_maybe_shift (Opcode Value u64 DivConstMagicU64 Value) Value)
(rule 2 (apply_div_const_magic_u64_maybe_shift opcode
numerator
divisor
(DivConstMagicU64.U64 _mul_by _do_add 0)
q3)
(apply_div_const_magic_u64_finish opcode numerator divisor q3))
(rule 1 (apply_div_const_magic_u64_maybe_shift opcode
numerator
divisor
(DivConstMagicU64.U64 _mul_by
_do_add
(u32_extract_non_zero shift_by))
q3)
(let ((qf Value (ushr $I64 q3 (iconst_u $I64 (u64_sub shift_by 1)))))
(apply_div_const_magic_u64_finish opcode numerator divisor qf)))
;; Now `qf` holds the final quotient. If necessary calculate the remainder
;; instead.
;;
;; if Opcode == Urem {
;; tt = imul qf, divisor
;; isub numerator, tt
;; } else {
;; qf
;; }
(decl apply_div_const_magic_u64_finish (Opcode Value u64 Value) Value)
(rule (apply_div_const_magic_u64_finish (Opcode.Udiv) _ _ qf) qf)
(rule (apply_div_const_magic_u64_finish (Opcode.Urem) numerator divisor qf)
(let ((tt Value (imul $I64 qf (iconst_u $I64 divisor))))
(isub $I64 numerator tt)))
;; Applying div-const magic for s32.
(decl apply_div_const_magic_s32 (Opcode Value i32) Value)
(rule (apply_div_const_magic_s32 opcode numerator divisor)
(apply_div_const_magic_s32_inner opcode numerator divisor (div_const_magic_s32 divisor)))
;; q0 = iconst.i32 mul_by
;; q1 = smulhi numerator, q0
(decl apply_div_const_magic_s32_inner (Opcode Value i32 DivConstMagicS32) Value)
(rule (apply_div_const_magic_s32_inner opcode
numerator
divisor
magic @ (DivConstMagicS32.S32 mul_by _shift_by))
(let ((q0 Value (iconst_s $I32 mul_by))
(q1 Value (smulhi $I32 numerator q0)))
(apply_div_const_magic_s32_add_sub opcode numerator divisor magic q1)))
;; q2 = if divisor > 0 && mul_by < 0 {
;; iadd q1, numerator
;; } else if divisor < 0 && mul_by > 0 {
;; isub q1, numerator
;; } else {
;; q1
;; };
(decl apply_div_const_magic_s32_add_sub (Opcode Value i32 DivConstMagicS32 Value) Value)
(rule 2 (apply_div_const_magic_s32_add_sub opcode
numerator
divisor
magic @ (DivConstMagicS32.S32 mul_by _shift_by)
q1)
(if-let true (i32_gt divisor 0))
(if-let true (i32_lt mul_by 0))
(let ((q2 Value (iadd $I32 q1 numerator)))
(apply_div_const_magic_s32_shift opcode numerator divisor magic q2)))
(rule 1 (apply_div_const_magic_s32_add_sub opcode
numerator
divisor
magic @ (DivConstMagicS32.S32 mul_by _shift_by)
q1)
(if-let true (i32_lt divisor 0))
(if-let true (i32_gt mul_by 0))
(let ((q2 Value (isub $I32 q1 numerator)))
(apply_div_const_magic_s32_shift opcode numerator divisor magic q2)))
(rule 0 (apply_div_const_magic_s32_add_sub opcode
numerator
divisor
magic
q1)
(apply_div_const_magic_s32_shift opcode numerator divisor magic q1))
;; q3 = sshr q2, shift_by
;; t1 = ushr q3, 31
;; qf = iadd q3, t1
(decl apply_div_const_magic_s32_shift (Opcode Value i32 DivConstMagicS32 Value) Value)
(rule (apply_div_const_magic_s32_shift opcode
numerator
divisor
magic @ (DivConstMagicS32.S32 _mul_by shift_by)
q2)
;; Note: let other rules clean up `q2` when `shift_by == 0`.
(let ((q3 Value (sshr $I32 q2 (iconst_s $I32 shift_by)))
(t1 Value (ushr $I32 q3 (iconst_s $I32 31)))
(qf Value (iadd $I32 q3 t1)))
(apply_div_const_magic_s32_finish opcode numerator divisor qf)))
;; Now `qf` holds the final quotient. If necessary, produce the remainder
;; instead.
;;
;; if Opcode == Srem {
;; tt = imul qf, divisor
;; isub numerator, tt
;; } else {
;; qf
;; }
(decl apply_div_const_magic_s32_finish (Opcode Value i32 Value) Value)
(rule (apply_div_const_magic_s32_finish (Opcode.Srem) numerator divisor qf)
(let ((tt Value (imul $I32 qf (iconst_s $I32 divisor))))
(isub $I32 numerator tt)))
(rule (apply_div_const_magic_s32_finish (Opcode.Sdiv) _numerator _divisor qf)
qf)
;; Applying div-const magic for s64.
(decl apply_div_const_magic_s64 (Opcode Value i64) Value)
(rule (apply_div_const_magic_s64 opcode numerator divisor)
(apply_div_const_magic_s64_inner opcode numerator divisor (div_const_magic_s64 divisor)))
;; q0 = iconst.i64 mul_by
;; q1 = smulhi numerator, q0
(decl apply_div_const_magic_s64_inner (Opcode Value i64 DivConstMagicS64) Value)
(rule (apply_div_const_magic_s64_inner opcode
numerator
divisor
magic @ (DivConstMagicS64.S64 mul_by _shift_by))
(let ((q0 Value (iconst_s $I64 mul_by))
(q1 Value (smulhi $I64 numerator q0)))
(apply_div_const_magic_s64_add_sub opcode numerator divisor magic q1)))
;; q2 = if divisor > 0 && mul_by < 0 {
;; iadd q1, numerator
;; } else if divisor < 0 && mul_by > 0 {
;; isub q1, numerator
;; } else {
;; q1
;; };
(decl apply_div_const_magic_s64_add_sub (Opcode Value i64 DivConstMagicS64 Value) Value)
(rule 2 (apply_div_const_magic_s64_add_sub opcode
numerator
divisor
magic @ (DivConstMagicS64.S64 mul_by _shift_by)
q1)
(if-let true (i64_gt divisor 0))
(if-let true (i64_lt mul_by 0))
(let ((q2 Value (iadd $I64 q1 numerator)))
(apply_div_const_magic_s64_shift opcode numerator divisor magic q2)))
(rule 1 (apply_div_const_magic_s64_add_sub opcode
numerator
divisor
magic @ (DivConstMagicS64.S64 mul_by _shift_by)
q1)
(if-let true (i64_lt divisor 0))
(if-let true (i64_gt mul_by 0))
(let ((q2 Value (isub $I64 q1 numerator)))
(apply_div_const_magic_s64_shift opcode numerator divisor magic q2)))
(rule 0 (apply_div_const_magic_s64_add_sub opcode
numerator
divisor
magic
q1)
(apply_div_const_magic_s64_shift opcode numerator divisor magic q1))
;; q3 = sshr q2, shift_by
;; t1 = ushr q3, 63
;; qf = iadd q3, t1
(decl apply_div_const_magic_s64_shift (Opcode Value i64 DivConstMagicS64 Value) Value)
(rule (apply_div_const_magic_s64_shift opcode
numerator
divisor
magic @ (DivConstMagicS64.S64 _mul_by shift_by)
q2)
;; Note: let other rules clean up `q2` when `shift_by == 0`.
(let ((q3 Value (sshr $I64 q2 (iconst_s $I64 shift_by)))
(t1 Value (ushr $I64 q3 (iconst_s $I64 63)))
(qf Value (iadd $I64 q3 t1)))
(apply_div_const_magic_s64_finish opcode numerator divisor qf)))
;; Now `qf` holds the final quotient. If necessary, produce the remainder
;; instead.
;;
;; if Opcode == Srem {
;; tt = imul qf, divisor
;; isub numerator, tt
;; } else {
;; qf
;; }
(decl apply_div_const_magic_s64_finish (Opcode Value i64 Value) Value)
(rule (apply_div_const_magic_s64_finish (Opcode.Srem) numerator divisor qf)
(let ((tt Value (imul $I64 qf (iconst_s $I64 divisor))))
(isub $I64 numerator tt)))
(rule (apply_div_const_magic_s64_finish (Opcode.Sdiv) _numerator _divisor qf)
qf)