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cranelift: Fix ireduce rules #8005

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Merged
jameysharp merged 1 commit into from
Feb 28, 2024
Merged

cranelift: Fix ireduce rules #8005

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53 changes: 10 additions & 43 deletions cranelift/codegen/src/opts/extends.isle
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Original file line number Diff line number Diff line change
Expand Up @@ -75,50 +75,17 @@
(rule (simplify (bxor bigty (uextend _ x@(value_type smallty)) (uextend _ y@(value_type smallty))))
(uextend bigty (bxor smallty x y)))

;; Matches values where `ireducing` them will not actually introduce another
;; instruction, since other rules will collapse them with the reduction.
(decl pure multi will_simplify_with_ireduce_rec (u8 Value) Value)
(rule (will_simplify_with_ireduce_rec _ x@(uextend _ _)) x)
(rule (will_simplify_with_ireduce_rec _ x@(sextend _ _)) x)
(rule (will_simplify_with_ireduce_rec _ x@(iconst _ _)) x)
(rule (will_simplify_with_ireduce_rec depth x@(unary_op _ _ a))
(if-let _ (u8_lt 0 depth))
(if-let _ (reducible_modular_op x))
(if-let _ (will_simplify_with_ireduce_rec (u8_sub depth 1) a))
x)
(rule (will_simplify_with_ireduce_rec depth x@(binary_op _ _ a b))
(if-let _ (u8_lt 0 depth))
(if-let _ (reducible_modular_op x))
(if-let _ (will_simplify_with_ireduce_rec (u8_sub depth 1) a))
(if-let _ (will_simplify_with_ireduce_rec (u8_sub depth 1) b))
x)

(decl pure multi will_simplify_with_ireduce (Value) Value)
(rule (will_simplify_with_ireduce x)
(will_simplify_with_ireduce_rec 2 x))

;; Replace `(small)(x OP y)` with `(small)x OP (small)y` in cases where that's
;; legal.
;; Matches values where the high bits of the input don't affect lower bits of
;; the output, and thus the inputs can be reduced before the operation rather
;; than doing the wide operation then reducing afterwards.
(decl pure multi reducible_modular_op (Value) Value)
(rule (reducible_modular_op x@(ineg _ _)) x)
(rule (reducible_modular_op x@(bnot _ _)) x)
(rule (reducible_modular_op x@(iadd _ _ _)) x)
(rule (reducible_modular_op x@(isub _ _ _)) x)
(rule (reducible_modular_op x@(imul _ _ _)) x)
(rule (reducible_modular_op x@(bor _ _ _)) x)
(rule (reducible_modular_op x@(bxor _ _ _)) x)
(rule (reducible_modular_op x@(band _ _ _)) x)
(rule (simplify (ireduce ty (ineg _ x))) (ineg ty (ireduce ty x)))
(rule (simplify (ireduce ty (bnot _ x))) (bnot ty (ireduce ty x)))

;; Replace `(small)(x OP y)` with `(small)x OP (small)y` in cases where that's
;; legal and it reduces the total number of instructions since the reductions
;; to the arguments simplify further.
(rule (simplify (ireduce smallty val@(unary_op _ op x)))
(if-let _ (reducible_modular_op val))
(if-let _ (will_simplify_with_ireduce x))
(unary_op smallty op (ireduce smallty x)))
(rule (simplify (ireduce smallty val@(binary_op _ op x y)))
(if-let _ (reducible_modular_op val))
(if-let _ (will_simplify_with_ireduce x))
(if-let _ (will_simplify_with_ireduce y))
(binary_op smallty op (ireduce smallty x) (ireduce smallty y)))
(rule (simplify (ireduce ty (iadd _ x y))) (iadd ty (ireduce ty x) (ireduce ty y)))
(rule (simplify (ireduce ty (isub _ x y))) (isub ty (ireduce ty x) (ireduce ty y)))
(rule (simplify (ireduce ty (imul _ x y))) (imul ty (ireduce ty x) (ireduce ty y)))
(rule (simplify (ireduce ty (bor _ x y))) (bor ty (ireduce ty x) (ireduce ty y)))
(rule (simplify (ireduce ty (bxor _ x y))) (bxor ty (ireduce ty x) (ireduce ty y)))
(rule (simplify (ireduce ty (band _ x y))) (band ty (ireduce ty x) (ireduce ty y)))
12 changes: 0 additions & 12 deletions cranelift/codegen/src/prelude_opt.isle
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Original file line number Diff line number Diff line change
Expand Up @@ -120,15 +120,3 @@
(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)

(decl unary_op (Type Opcode Value) Value)
(extractor (unary_op ty opcode x)
(inst_data ty (InstructionData.Unary opcode x)))
(rule (unary_op ty opcode x)
(make_inst ty (InstructionData.Unary opcode x)))

(decl binary_op (Type Opcode Value Value) Value)
(extractor (binary_op ty opcode x y)
(inst_data ty (InstructionData.Binary opcode (value_array_2 x y))))
(rule (binary_op ty opcode x y)
(make_inst ty (InstructionData.Binary opcode (value_array_2_ctor x y))))