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cmd/compile: use soft-float routines for soft-float targets
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Updates #18162 (mostly fixes)

Change-Id: I35bcb8a688bdaa432adb0ddbb73a2f7adda47b9e
Reviewed-on: https://go-review.googlesource.com/37958
Run-TryBot: Brad Fitzpatrick <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Cherry Zhang <[email protected]>
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@bradfitz
Vladimir Stefanovic authored and bradfitz committed Nov 30, 2017
1 parent f0f62fc commit 6be1c09
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Showing 11 changed files with 271 additions and 41 deletions.
7 changes: 4 additions & 3 deletions src/cmd/compile/internal/gc/go.go
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Original file line number Diff line number Diff line change
Expand Up @@ -243,9 +243,10 @@ var autogeneratedPos src.XPos
type Arch struct {
LinkArch *obj.LinkArch

REGSP int
MAXWIDTH int64
Use387 bool // should 386 backend use 387 FP instructions instead of sse2.
REGSP int
MAXWIDTH int64
Use387 bool // should 386 backend use 387 FP instructions instead of sse2.
SoftFloat bool

PadFrame func(int64) int64
ZeroRange func(*Progs, *obj.Prog, int64, int64, *uint32) *obj.Prog
Expand Down
6 changes: 6 additions & 0 deletions src/cmd/compile/internal/gc/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,7 @@ var (
Debug_locationlist int
Debug_typecheckinl int
Debug_gendwarfinl int
Debug_softfloat int
)

// Debug arguments.
Expand Down Expand Up @@ -78,6 +79,7 @@ var debugtab = []struct {
{"locationlists", "print information about DWARF location list creation", &Debug_locationlist},
{"typecheckinl", "eager typechecking of inline function bodies", &Debug_typecheckinl},
{"dwarfinl", "print information about DWARF inlined function creation", &Debug_gendwarfinl},
{"softfloat", "force compiler to emit soft-float code", &Debug_softfloat},
}

const debugHelpHeader = `usage: -d arg[,arg]* and arg is <key>[=<value>]
Expand Down Expand Up @@ -393,6 +395,10 @@ func Main(archInit func(*Arch)) {
dwarf.EnableLogging(Debug_gendwarfinl != 0)
}

if Debug_softfloat != 0 {
thearch.SoftFloat = true
}

// enable inlining. for now:
// default: inlining on. (debug['l'] == 1)
// -l: inlining off (debug['l'] == 0)
Expand Down
181 changes: 149 additions & 32 deletions src/cmd/compile/internal/gc/ssa.go
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,11 @@ func initssaconfig() {
Float64Ptr: types.NewPtr(types.Types[TFLOAT64]),
BytePtrPtr: types.NewPtr(types.NewPtr(types.Types[TUINT8])),
}

if thearch.SoftFloat {
softfloatInit()
}

// Generate a few pointer types that are uncommon in the frontend but common in the backend.
// Caching is disabled in the backend, so generating these here avoids allocations.
_ = types.NewPtr(types.Types[TINTER]) // *interface{}
Expand All @@ -68,6 +73,7 @@ func initssaconfig() {
if thearch.LinkArch.Name == "386" {
ssaConfig.Set387(thearch.Use387)
}
ssaConfig.SoftFloat = thearch.SoftFloat
ssaCaches = make([]ssa.Cache, nBackendWorkers)

// Set up some runtime functions we'll need to call.
Expand Down Expand Up @@ -139,6 +145,7 @@ func buildssa(fn *Node, worker int) *ssa.Func {
}
s.exitCode = fn.Func.Exit
s.panics = map[funcLine]*ssa.Block{}
s.softFloat = s.config.SoftFloat

if name == os.Getenv("GOSSAFUNC") {
s.f.HTMLWriter = ssa.NewHTMLWriter("ssa.html", s.f.Frontend(), name)
Expand Down Expand Up @@ -310,6 +317,7 @@ type state struct {

cgoUnsafeArgs bool
hasdefer bool // whether the function contains a defer statement
softFloat bool
}

type funcLine struct {
Expand Down Expand Up @@ -553,6 +561,25 @@ func (s *state) constOffPtrSP(t *types.Type, c int64) *ssa.Value {
return s.f.ConstOffPtrSP(s.peekPos(), t, c, s.sp)
}

// newValueOrSfCall* are wrappers around newValue*, which may create a call to a
// soft-float runtime function instead (when emitting soft-float code).
func (s *state) newValueOrSfCall1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
if s.softFloat {
if c, ok := s.sfcall(op, arg); ok {
return c
}
}
return s.newValue1(op, t, arg)
}
func (s *state) newValueOrSfCall2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
if s.softFloat {
if c, ok := s.sfcall(op, arg0, arg1); ok {
return c
}
}
return s.newValue2(op, t, arg0, arg1)
}

// stmtList converts the statement list n to SSA and adds it to s.
func (s *state) stmtList(l Nodes) {
for _, n := range l.Slice() {
Expand Down Expand Up @@ -1689,18 +1716,18 @@ func (s *state) expr(n *Node) *ssa.Value {

if ft.IsFloat() || tt.IsFloat() {
conv, ok := fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]
if s.config.RegSize == 4 && thearch.LinkArch.Family != sys.MIPS {
if s.config.RegSize == 4 && thearch.LinkArch.Family != sys.MIPS && !s.softFloat {
if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
conv = conv1
}
}
if thearch.LinkArch.Family == sys.ARM64 {
if thearch.LinkArch.Family == sys.ARM64 || s.softFloat {
if conv1, ok1 := uint64fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
conv = conv1
}
}

if thearch.LinkArch.Family == sys.MIPS {
if thearch.LinkArch.Family == sys.MIPS && !s.softFloat {
if ft.Size() == 4 && ft.IsInteger() && !ft.IsSigned() {
// tt is float32 or float64, and ft is also unsigned
if tt.Size() == 4 {
Expand Down Expand Up @@ -1731,12 +1758,12 @@ func (s *state) expr(n *Node) *ssa.Value {
if op2 == ssa.OpCopy {
return x
}
return s.newValue1(op2, n.Type, x)
return s.newValueOrSfCall1(op2, n.Type, x)
}
if op2 == ssa.OpCopy {
return s.newValue1(op1, n.Type, x)
return s.newValueOrSfCall1(op1, n.Type, x)
}
return s.newValue1(op2, n.Type, s.newValue1(op1, types.Types[it], x))
return s.newValueOrSfCall1(op2, n.Type, s.newValueOrSfCall1(op1, types.Types[it], x))
}
// Tricky 64-bit unsigned cases.
if ft.IsInteger() {
Expand Down Expand Up @@ -1781,8 +1808,8 @@ func (s *state) expr(n *Node) *ssa.Value {
ftp := floatForComplex(ft)
ttp := floatForComplex(tt)
return s.newValue2(ssa.OpComplexMake, tt,
s.newValue1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, x)),
s.newValue1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, x)))
s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, x)),
s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, x)))
}

s.Fatalf("unhandled OCONV %s -> %s", n.Left.Type.Etype, n.Type.Etype)
Expand All @@ -1799,8 +1826,8 @@ func (s *state) expr(n *Node) *ssa.Value {
if n.Left.Type.IsComplex() {
pt := floatForComplex(n.Left.Type)
op := s.ssaOp(OEQ, pt)
r := s.newValue2(op, types.Types[TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
i := s.newValue2(op, types.Types[TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
r := s.newValueOrSfCall2(op, types.Types[TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
i := s.newValueOrSfCall2(op, types.Types[TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
c := s.newValue2(ssa.OpAndB, types.Types[TBOOL], r, i)
switch n.Op {
case OEQ:
Expand All @@ -1811,6 +1838,9 @@ func (s *state) expr(n *Node) *ssa.Value {
s.Fatalf("ordered complex compare %v", n.Op)
}
}
if n.Left.Type.IsFloat() {
return s.newValueOrSfCall2(s.ssaOp(n.Op, n.Left.Type), types.Types[TBOOL], a, b)
}
return s.newValue2(s.ssaOp(n.Op, n.Left.Type), types.Types[TBOOL], a, b)
case OMUL:
a := s.expr(n.Left)
Expand All @@ -1828,22 +1858,27 @@ func (s *state) expr(n *Node) *ssa.Value {
bimag := s.newValue1(ssa.OpComplexImag, pt, b)

if pt != wt { // Widen for calculation
areal = s.newValue1(ssa.OpCvt32Fto64F, wt, areal)
breal = s.newValue1(ssa.OpCvt32Fto64F, wt, breal)
aimag = s.newValue1(ssa.OpCvt32Fto64F, wt, aimag)
bimag = s.newValue1(ssa.OpCvt32Fto64F, wt, bimag)
areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
}

xreal := s.newValue2(subop, wt, s.newValue2(mulop, wt, areal, breal), s.newValue2(mulop, wt, aimag, bimag))
ximag := s.newValue2(addop, wt, s.newValue2(mulop, wt, areal, bimag), s.newValue2(mulop, wt, aimag, breal))
xreal := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
ximag := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, bimag), s.newValueOrSfCall2(mulop, wt, aimag, breal))

if pt != wt { // Narrow to store back
xreal = s.newValue1(ssa.OpCvt64Fto32F, pt, xreal)
ximag = s.newValue1(ssa.OpCvt64Fto32F, pt, ximag)
xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
}

return s.newValue2(ssa.OpComplexMake, n.Type, xreal, ximag)
}

if n.Type.IsFloat() {
return s.newValueOrSfCall2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
}

return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)

case ODIV:
Expand All @@ -1866,31 +1901,31 @@ func (s *state) expr(n *Node) *ssa.Value {
bimag := s.newValue1(ssa.OpComplexImag, pt, b)

if pt != wt { // Widen for calculation
areal = s.newValue1(ssa.OpCvt32Fto64F, wt, areal)
breal = s.newValue1(ssa.OpCvt32Fto64F, wt, breal)
aimag = s.newValue1(ssa.OpCvt32Fto64F, wt, aimag)
bimag = s.newValue1(ssa.OpCvt32Fto64F, wt, bimag)
areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
}

denom := s.newValue2(addop, wt, s.newValue2(mulop, wt, breal, breal), s.newValue2(mulop, wt, bimag, bimag))
xreal := s.newValue2(addop, wt, s.newValue2(mulop, wt, areal, breal), s.newValue2(mulop, wt, aimag, bimag))
ximag := s.newValue2(subop, wt, s.newValue2(mulop, wt, aimag, breal), s.newValue2(mulop, wt, areal, bimag))
denom := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, breal, breal), s.newValueOrSfCall2(mulop, wt, bimag, bimag))
xreal := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
ximag := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, aimag, breal), s.newValueOrSfCall2(mulop, wt, areal, bimag))

// TODO not sure if this is best done in wide precision or narrow
// Double-rounding might be an issue.
// Note that the pre-SSA implementation does the entire calculation
// in wide format, so wide is compatible.
xreal = s.newValue2(divop, wt, xreal, denom)
ximag = s.newValue2(divop, wt, ximag, denom)
xreal = s.newValueOrSfCall2(divop, wt, xreal, denom)
ximag = s.newValueOrSfCall2(divop, wt, ximag, denom)

if pt != wt { // Narrow to store back
xreal = s.newValue1(ssa.OpCvt64Fto32F, pt, xreal)
ximag = s.newValue1(ssa.OpCvt64Fto32F, pt, ximag)
xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
}
return s.newValue2(ssa.OpComplexMake, n.Type, xreal, ximag)
}
if n.Type.IsFloat() {
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
return s.newValueOrSfCall2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
}
return s.intDivide(n, a, b)
case OMOD:
Expand All @@ -1904,8 +1939,11 @@ func (s *state) expr(n *Node) *ssa.Value {
pt := floatForComplex(n.Type)
op := s.ssaOp(n.Op, pt)
return s.newValue2(ssa.OpComplexMake, n.Type,
s.newValue2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
s.newValue2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
}
if n.Type.IsFloat() {
return s.newValueOrSfCall2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
}
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case OAND, OOR, OXOR:
Expand Down Expand Up @@ -2564,6 +2602,79 @@ const (
callGo
)

type sfRtCallDef struct {
rtfn *obj.LSym
rtype types.EType
}

var softFloatOps map[ssa.Op]sfRtCallDef

func softfloatInit() {
// Some of these operations get transformed by sfcall.
softFloatOps = map[ssa.Op]sfRtCallDef{
ssa.OpAdd32F: sfRtCallDef{sysfunc("fadd32"), TFLOAT32},
ssa.OpAdd64F: sfRtCallDef{sysfunc("fadd64"), TFLOAT64},
ssa.OpSub32F: sfRtCallDef{sysfunc("fadd32"), TFLOAT32},
ssa.OpSub64F: sfRtCallDef{sysfunc("fadd64"), TFLOAT64},
ssa.OpMul32F: sfRtCallDef{sysfunc("fmul32"), TFLOAT32},
ssa.OpMul64F: sfRtCallDef{sysfunc("fmul64"), TFLOAT64},
ssa.OpDiv32F: sfRtCallDef{sysfunc("fdiv32"), TFLOAT32},
ssa.OpDiv64F: sfRtCallDef{sysfunc("fdiv64"), TFLOAT64},

ssa.OpEq64F: sfRtCallDef{sysfunc("feq64"), TBOOL},
ssa.OpEq32F: sfRtCallDef{sysfunc("feq32"), TBOOL},
ssa.OpNeq64F: sfRtCallDef{sysfunc("feq64"), TBOOL},
ssa.OpNeq32F: sfRtCallDef{sysfunc("feq32"), TBOOL},
ssa.OpLess64F: sfRtCallDef{sysfunc("fgt64"), TBOOL},
ssa.OpLess32F: sfRtCallDef{sysfunc("fgt32"), TBOOL},
ssa.OpGreater64F: sfRtCallDef{sysfunc("fgt64"), TBOOL},
ssa.OpGreater32F: sfRtCallDef{sysfunc("fgt32"), TBOOL},
ssa.OpLeq64F: sfRtCallDef{sysfunc("fge64"), TBOOL},
ssa.OpLeq32F: sfRtCallDef{sysfunc("fge32"), TBOOL},
ssa.OpGeq64F: sfRtCallDef{sysfunc("fge64"), TBOOL},
ssa.OpGeq32F: sfRtCallDef{sysfunc("fge32"), TBOOL},

ssa.OpCvt32to32F: sfRtCallDef{sysfunc("fint32to32"), TFLOAT32},
ssa.OpCvt32Fto32: sfRtCallDef{sysfunc("f32toint32"), TINT32},
ssa.OpCvt64to32F: sfRtCallDef{sysfunc("fint64to32"), TFLOAT32},
ssa.OpCvt32Fto64: sfRtCallDef{sysfunc("f32toint64"), TINT64},
ssa.OpCvt64Uto32F: sfRtCallDef{sysfunc("fuint64to32"), TFLOAT32},
ssa.OpCvt32Fto64U: sfRtCallDef{sysfunc("f32touint64"), TUINT64},
ssa.OpCvt32to64F: sfRtCallDef{sysfunc("fint32to64"), TFLOAT64},
ssa.OpCvt64Fto32: sfRtCallDef{sysfunc("f64toint32"), TINT32},
ssa.OpCvt64to64F: sfRtCallDef{sysfunc("fint64to64"), TFLOAT64},
ssa.OpCvt64Fto64: sfRtCallDef{sysfunc("f64toint64"), TINT64},
ssa.OpCvt64Uto64F: sfRtCallDef{sysfunc("fuint64to64"), TFLOAT64},
ssa.OpCvt64Fto64U: sfRtCallDef{sysfunc("f64touint64"), TUINT64},
ssa.OpCvt32Fto64F: sfRtCallDef{sysfunc("f32to64"), TFLOAT64},
ssa.OpCvt64Fto32F: sfRtCallDef{sysfunc("f64to32"), TFLOAT32},
}
}

// TODO: do not emit sfcall if operation can be optimized to constant in later
// opt phase
func (s *state) sfcall(op ssa.Op, args ...*ssa.Value) (*ssa.Value, bool) {
if callDef, ok := softFloatOps[op]; ok {
switch op {
case ssa.OpLess32F,
ssa.OpLess64F,
ssa.OpLeq32F,
ssa.OpLeq64F:
args[0], args[1] = args[1], args[0]
case ssa.OpSub32F,
ssa.OpSub64F:
args[1] = s.newValue1(s.ssaOp(OMINUS, types.Types[callDef.rtype]), args[1].Type, args[1])
}

result := s.rtcall(callDef.rtfn, true, []*types.Type{types.Types[callDef.rtype]}, args...)[0]
if op == ssa.OpNeq32F || op == ssa.OpNeq64F {
result = s.newValue1(ssa.OpNot, result.Type, result)
}
return result, true
}
return nil, false
}

var intrinsics map[intrinsicKey]intrinsicBuilder

// An intrinsicBuilder converts a call node n into an ssa value that
Expand Down Expand Up @@ -3134,6 +3245,12 @@ func findIntrinsic(sym *types.Sym) intrinsicBuilder {
// We can't intrinsify them.
return nil
}
// Skip intrinsifying math functions (which may contain hard-float
// instructions) when soft-float
if thearch.SoftFloat && pkg == "math" {
return nil
}

fn := sym.Name
return intrinsics[intrinsicKey{thearch.LinkArch.Arch, pkg, fn}]
}
Expand Down
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