c8791073d6
* cranelift: Remove iconst.i128 * bugpoint: Report Changed when only one instruction is mutated * cranelift: Fix egraph bxor rule * cranelift: Remove some simple_preopt opts for i128
204 lines
6.7 KiB
Common Lisp
204 lines
6.7 KiB
Common Lisp
;; Algebraic optimizations.
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;; Rules here are allowed to rewrite pure expressions arbitrarily,
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;; using the same inputs as the original, or fewer. In other words, we
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;; cannot pull a new eclass id out of thin air and refer to it, other
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;; than a piece of the input or a new node that we construct; but we
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;; can freely rewrite e.g. `x+y-y` to `x`.
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;; uextend/sextend of a constant.
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(rule (simplify (uextend $I64 (iconst $I32 (u64_from_imm64 imm))))
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(iconst $I64 (imm64 (u64_uextend_u32 imm))))
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(rule (simplify (sextend $I64 (iconst $I32 (u64_from_imm64 imm))))
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(iconst $I64 (imm64 (u64_sextend_u32 imm))))
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;; x+0 == 0+x == x.
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(rule (simplify (iadd ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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(rule (simplify (iadd ty
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(iconst ty (u64_from_imm64 0))
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x))
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(subsume x))
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;; x-0 == x.
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(rule (simplify (isub ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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;; 0-x == (ineg x).
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(rule (simplify (isub ty
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(iconst ty (u64_from_imm64 0))
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x))
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(ineg ty x))
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;; x*1 == 1*x == x.
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(rule (simplify (imul ty
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x
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(iconst ty (u64_from_imm64 1))))
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(subsume x))
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(rule (simplify (imul ty
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(iconst ty (u64_from_imm64 1))
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x))
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(subsume x))
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;; x*0 == 0*x == x.
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(rule (simplify (imul ty
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x
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(iconst ty (u64_from_imm64 0))))
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(iconst ty (imm64 0)))
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(rule (simplify (imul ty
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(iconst ty (u64_from_imm64 0))
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x))
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(iconst ty (imm64 0)))
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;; x/1 == x.
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(rule (simplify (sdiv ty
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x
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(iconst ty (u64_from_imm64 1))))
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(subsume x))
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(rule (simplify (udiv ty
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x
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(iconst ty (u64_from_imm64 1))))
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(subsume x))
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;; x>>0 == x<<0 == x rotr 0 == x rotl 0 == x.
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(rule (simplify (ishl ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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(rule (simplify (ushr ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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(rule (simplify (sshr ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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(rule (simplify (rotr ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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(rule (simplify (rotl ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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;; x | 0 == 0 | x == x | x == x.
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(rule (simplify (bor ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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(rule (simplify (bor ty
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(iconst ty (u64_from_imm64 0))
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x))
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(subsume x))
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(rule (simplify (bor ty x x))
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(subsume x))
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;; x ^ 0 == 0 ^ x == x.
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(rule (simplify (bxor ty
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x
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(iconst ty (u64_from_imm64 0))))
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(subsume x))
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(rule (simplify (bxor ty
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(iconst ty (u64_from_imm64 0))
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x))
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(subsume x))
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;; x ^ x == 0.
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(rule (simplify (bxor (fits_in_64 ty) x x))
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(subsume (iconst ty (imm64 0))))
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;; x ^ not(x) == not(x) ^ x == -1.
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(rule (simplify (bxor $I32 x (bnot $I32 x))) (subsume (iconst $I32 (imm64 0xffff_ffff))))
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(rule (simplify (bxor $I32 (bnot $I32 x) x)) (subsume (iconst $I32 (imm64 0xffff_ffff))))
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(rule (simplify (bxor $I64 x (bnot $I64 x))) (subsume (iconst $I64 (imm64 0xffff_ffff_ffff_ffff))))
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(rule (simplify (bxor $I64 (bnot $I64 x) x)) (subsume (iconst $I64 (imm64 0xffff_ffff_ffff_ffff))))
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;; x & -1 == -1 & x == x & x == x.
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(rule (simplify (band ty x x)) x)
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(rule (simplify (band $I32 x (iconst $I32 (u64_from_imm64 0xffff_ffff)))) (subsume x))
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(rule (simplify (band $I32 (iconst $I32 (u64_from_imm64 0xffff_ffff)) x)) (subsume x))
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(rule (simplify (band $I64 x (iconst $I64 (u64_from_imm64 0xffff_ffff_ffff_ffff)))) (subsume x))
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(rule (simplify (band $I64 (iconst $I64 (u64_from_imm64 0xffff_ffff_ffff_ffff)) x)) (subsume x))
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;; x & 0 == 0 & x == 0.
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(rule (simplify (band ty x (iconst ty (u64_from_imm64 0)))) (iconst ty (imm64 0)))
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(rule (simplify (band ty (iconst ty (u64_from_imm64 0)) x)) (iconst ty (imm64 0)))
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;; not(not(x)) == x.
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(rule (simplify (bnot ty (bnot ty x))) (subsume x))
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;; DeMorgan's rule (two versions):
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;; bnot(bor(x, y)) == band(bnot(x), bnot(y))
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(rule (simplify (bnot ty (bor ty x y)))
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(band ty (bnot ty x) (bnot ty y)))
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;; bnot(band(x, y)) == bor(bnot(x), bnot(y))
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(rule (simplify (bnot ty (band t x y)))
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(bor ty (bnot ty x) (bnot ty y)))
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;; x*2 == 2*x == x+x.
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(rule (simplify (imul ty x (iconst _ (simm32 2))))
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(iadd ty x x))
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(rule (simplify (imul ty (iconst _ (simm32 2)) x))
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(iadd ty x x))
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;; x<<32>>32: uextend/sextend 32->64.
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(rule (simplify (ushr $I64 (ishl $I64 (uextend $I64 x @ (eclass_type $I32)) (iconst _ (simm32 32))) (iconst _ (simm32 32))))
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(uextend $I64 x))
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(rule (simplify (sshr $I64 (ishl $I64 (uextend $I64 x @ (eclass_type $I32)) (iconst _ (simm32 32))) (iconst _ (simm32 32))))
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(sextend $I64 x))
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;; TODO: strength reduction: mul/div to shifts
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;; TODO: div/rem by constants -> magic multiplications
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;; Reassociate when it benefits LICM.
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(rule (simplify (iadd ty (iadd ty x y) z))
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(if-let (at_loop_level lx _) x)
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(if-let (at_loop_level ly _) y)
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(if-let (at_loop_level lz _) z)
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(if (u8_lt lx ly))
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(if (u8_lt lz ly))
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(iadd ty (iadd ty x z) y))
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(rule (simplify (iadd ty (iadd ty x y) z))
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(if-let (at_loop_level lx _) x)
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(if-let (at_loop_level ly _) y)
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(if-let (at_loop_level lz _) z)
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(if (u8_lt ly lx))
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(if (u8_lt lz lx))
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(iadd ty (iadd ty y z) x))
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;; Rematerialize ALU-op-with-imm and iconsts in each block where they're
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;; used. This is neutral (add-with-imm) or positive (iconst) for
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;; register pressure, and these ops are very cheap.
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(rule (simplify x @ (iadd _ (iconst _ _) _))
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(remat x))
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(rule (simplify x @ (iadd _ _ (iconst _ _)))
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(remat x))
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(rule (simplify x @ (isub _ (iconst _ _) _))
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(remat x))
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(rule (simplify x @ (isub _ _ (iconst _ _)))
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(remat x))
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(rule (simplify x @ (band _ (iconst _ _) _))
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(remat x))
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(rule (simplify x @ (band _ _ (iconst _ _)))
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(remat x))
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(rule (simplify x @ (bor _ (iconst _ _) _))
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(remat x))
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(rule (simplify x @ (bor _ _ (iconst _ _)))
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(remat x))
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(rule (simplify x @ (bxor _ (iconst _ _) _))
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(remat x))
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(rule (simplify x @ (bxor _ _ (iconst _ _)))
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(remat x))
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(rule (simplify x @ (bnot _ _))
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(remat x))
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(rule (simplify x @ (iconst _ _))
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(remat x))
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(rule (simplify x @ (f32const _ _))
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(remat x))
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(rule (simplify x @ (f64const _ _))
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(remat x))
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