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[Cranelift] (x & y) | ~(x ^ y) => ~(x ^ y) #12686

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Merged
fitzgen merged 2 commits into from
Feb 27, 2026
+39 −0
Merged

[Cranelift] (x & y) | ~(x ^ y) => ~(x ^ y) #12686

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e2ddb12
cranelift: simplify bor(and, not(xor)) to not(xor)
myunbin Feb 27, 2026
ae49230
cranelift: extend bor(and, not(xor)) simplify coverage
myunbin Feb 27, 2026
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10 changes: 10 additions & 0 deletions cranelift/codegen/src/opts/bitops.isle
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Original file line number Diff line number Diff line change
Expand Up @@ -225,3 +225,13 @@
(rule (simplify
(bxor ty (band ty z x) (band ty z y)))
(band ty z (bxor ty x y)))

; (x & y) | ~(x ^ y) => ~(x ^ y)
(rule (simplify (bor ty (band ty x y) (bnot ty (bxor ty x y)))) (bnot ty (bxor ty x y)))
(rule (simplify (bor ty (bnot ty (bxor ty x y)) (band ty x y))) (bnot ty (bxor ty x y)))
(rule (simplify (bor ty (band ty x y) (bnot ty (bxor ty y x)))) (bnot ty (bxor ty x y)))
(rule (simplify (bor ty (bnot ty (bxor ty y x)) (band ty x y))) (bnot ty (bxor ty x y)))
(rule (simplify (bor ty (band ty y x) (bnot ty (bxor ty x y)))) (bnot ty (bxor ty x y)))
(rule (simplify (bor ty (bnot ty (bxor ty x y)) (band ty y x))) (bnot ty (bxor ty x y)))
(rule (simplify (bor ty (band ty y x) (bnot ty (bxor ty y x)))) (bnot ty (bxor ty x y)))
(rule (simplify (bor ty (bnot ty (bxor ty y x)) (band ty y x))) (bnot ty (bxor ty x y)))
16 changes: 16 additions & 0 deletions cranelift/filetests/filetests/egraph/fold-bitops.clif
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Expand Up @@ -74,3 +74,19 @@ block0(v0: i32, v1: i32, v2: i32):
; return v7
; }

;; (bor ty (band ty x y) (bnot ty (bxor ty x y))) -> (bnot ty (bxor ty x y))
function %test_bor_band_bnot_bxor(i32, i32) -> i32 fast {
block0(v0: i32, v1: i32):
v2 = band v0, v1
v3 = bxor v0, v1
v4 = bnot v3
v5 = bor v2, v4
return v5
}

; function %test_bor_band_bnot_bxor(i32, i32) -> i32 fast {
; block0(v0: i32, v1: i32):
; v6 = bxor v1, v0
; v7 = bnot v6
; return v7
; }
13 changes: 13 additions & 0 deletions cranelift/filetests/filetests/runtests/bitops.clif
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Expand Up @@ -232,3 +232,16 @@ block0(v0: i32, v1: i32, v2: i32):

; run: %test_bxor_band_band(2, 1, 1) == 0

function %test_bor_band_bnot_bxor(i32, i32) -> i32 fast {
block0(v0: i32, v1: i32):
v2 = band v0, v1
v3 = bxor v0, v1
v4 = bnot v3
v5 = bor v2, v4
return v5
}

; run: %test_bor_band_bnot_bxor(0, 0) == 0xffffffff
; run: %test_bor_band_bnot_bxor(1, 1) == 0xffffffff
; run: %test_bor_band_bnot_bxor(0, 1) == 0xfffffffe
; run: %test_bor_band_bnot_bxor(2, 1) == 0xfffffffc
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