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cranelift: simplify ineg(ineg(x)) to x #6033

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Merged
alexcrichton merged 1 commit into from
Mar 17, 2023
Merged

cranelift: simplify ineg(ineg(x)) to x #6033

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3 changes: 3 additions & 0 deletions cranelift/codegen/src/opts/algebraic.isle
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,9 @@
x))
(ineg ty x))

;; ineg(ineg(x)) == x.
(rule (simplify (ineg ty (ineg ty x))) (subsume x))

;; x*1 == 1*x == x.
(rule (simplify (imul ty
x
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8 changes: 8 additions & 0 deletions cranelift/filetests/filetests/egraph/algebraic.clif
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Expand Up @@ -224,6 +224,14 @@ block0(v0: i8):
; check: return v5
}

function %double_ineg(i32) -> i32 {
block0(v0: i32):
v1 = ineg v0
v2 = ineg v1
return v2
; check: return v0
}

function %or_and_y_with_not_y_i8(i8, i8) -> i8 {
block0(v0: i8, v1: i8):
v2 = band v0, v1
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