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cmd/compile: change cmplx{mpy,div} into Mpcplx methods

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Change-Id: Icae55fe4fa1bb8e4f2f83b7c69e08d30a5559d9e
Reviewed-on: https://go-review.googlesource.com/105047
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Matthew Dempsky 2018-04-06 09:44:29 -07:00
parent fcb7488add
commit 27493187ed
2 changed files with 73 additions and 94 deletions
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96
src/cmd/compile/internal/gc/const.go
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@ -1014,10 +1014,10 @@ func evconst(n *Node) {
v.U.(*Mpcplx).Imag.Sub(&rv.U.(*Mpcplx).Imag)
case OMUL_ | CTCPLX_:
cmplxmpy(v.U.(*Mpcplx), rv.U.(*Mpcplx))
v.U.(*Mpcplx).Mul(rv.U.(*Mpcplx))
case ODIV_ | CTCPLX_:
if !cmplxdiv(v.U.(*Mpcplx), rv.U.(*Mpcplx)) {
if !v.U.(*Mpcplx).Div(rv.U.(*Mpcplx)) {
yyerror("complex division by zero")
rv.U.(*Mpcplx).Real.SetFloat64(1.0)
rv.U.(*Mpcplx).Imag.SetFloat64(0.0)
@ -1522,98 +1522,6 @@ func nonnegintconst(n *Node) int64 {
return vi.Int64()
}
// complex multiply v *= rv
// (a, b) * (c, d) = (a*c - b*d, b*c + a*d)
func cmplxmpy(v *Mpcplx, rv *Mpcplx) {
var ac Mpflt
var bd Mpflt
var bc Mpflt
var ad Mpflt
ac.Set(&v.Real)
ac.Mul(&rv.Real) // ac
bd.Set(&v.Imag)
bd.Mul(&rv.Imag) // bd
bc.Set(&v.Imag)
bc.Mul(&rv.Real) // bc
ad.Set(&v.Real)
ad.Mul(&rv.Imag) // ad
v.Real.Set(&ac)
v.Real.Sub(&bd) // ac-bd
v.Imag.Set(&bc)
v.Imag.Add(&ad) // bc+ad
}
// complex divide v /= rv
// (a, b) / (c, d) = ((a*c + b*d), (b*c - a*d))/(c*c + d*d)
func cmplxdiv(v *Mpcplx, rv *Mpcplx) bool {
if rv.Real.CmpFloat64(0) == 0 && rv.Imag.CmpFloat64(0) == 0 {
return false
}
var ac Mpflt
var bd Mpflt
var bc Mpflt
var ad Mpflt
var cc_plus_dd Mpflt
cc_plus_dd.Set(&rv.Real)
cc_plus_dd.Mul(&rv.Real) // cc
ac.Set(&rv.Imag)
ac.Mul(&rv.Imag) // dd
cc_plus_dd.Add(&ac) // cc+dd
// We already checked that c and d are not both zero, but we can't
// assume that c²+d² != 0 follows, because for tiny values of c
// and/or d c²+d² can underflow to zero. Check that c²+d² is
// nonzero,return if it's not.
if cc_plus_dd.CmpFloat64(0) == 0 {
return false
}
ac.Set(&v.Real)
ac.Mul(&rv.Real) // ac
bd.Set(&v.Imag)
bd.Mul(&rv.Imag) // bd
bc.Set(&v.Imag)
bc.Mul(&rv.Real) // bc
ad.Set(&v.Real)
ad.Mul(&rv.Imag) // ad
v.Real.Set(&ac)
v.Real.Add(&bd) // ac+bd
v.Real.Quo(&cc_plus_dd) // (ac+bd)/(cc+dd)
v.Imag.Set(&bc)
v.Imag.Sub(&ad) // bc-ad
v.Imag.Quo(&cc_plus_dd) // (bc+ad)/(cc+dd)
return true
}
// Is n a Go language constant (as opposed to a compile-time constant)?
// Expressions derived from nil, like string([]byte(nil)), while they
// may be known at compile time, are not Go language constants.