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[dev.ssa] cmd/compile: fix fp constant loads for 386+PIC

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In position-independent 386 code, loading floating-point constants from
the constant pool requires two steps: materializing the address of
the constant pool entry (requires calling a thunk) and then loading
from that address.

Before this CL, the materializing happened implicitly in CX, which
clobbered that register.

Change-Id: Id094e0fb2d3be211089f299e8f7c89c315de0a87
Reviewed-on: https://go-review.googlesource.com/26811
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Keith Randall 2016-08-11 09:49:48 -07:00
parent ed1ad8f56c
commit 8f955d3664
6 changed files with 196 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
src/cmd/compile/internal/ssa/gen/386.rules
View File

@ -70,8 +70,10 @@
(Neg32 x) -> (NEGL x)
(Neg16 x) -> (NEGL x)
(Neg8 x) -> (NEGL x)
(Neg32F x) -> (PXOR x (MOVSSconst <config.Frontend().TypeFloat32()> [f2i(math.Copysign(0, -1))]))
(Neg64F x) -> (PXOR x (MOVSDconst <config.Frontend().TypeFloat64()> [f2i(math.Copysign(0, -1))]))
(Neg32F x) && !config.use387 -> (PXOR x (MOVSSconst <config.Frontend().TypeFloat32()> [f2i(math.Copysign(0, -1))]))
(Neg64F x) && !config.use387 -> (PXOR x (MOVSDconst <config.Frontend().TypeFloat64()> [f2i(math.Copysign(0, -1))]))
(Neg32F x) && config.use387 -> (FCHS x)
(Neg64F x) && config.use387 -> (FCHS x)
(Com32 x) -> (NOTL x)
(Com16 x) -> (NOTL x)
@ -1250,3 +1252,8 @@
&& x.Uses == 1
&& clobber(x)
-> (MOVLstoreidx1 [i-2] {s} p (SHLLconst <idx.Type> [1] idx) w0 mem)
// For PIC, break floating-point constant loading into two instructions so we have
// a register to use for holding the address of the constant pool entry.
(MOVSSconst [c]) && config.ctxt.Flag_shared -> (MOVSSconst2 (MOVSSconst1 [c]))
(MOVSDconst [c]) && config.ctxt.Flag_shared -> (MOVSDconst2 (MOVSDconst1 [c]))

12
src/cmd/compile/internal/ssa/gen/386Ops.go
View File

@ -463,6 +463,18 @@ func init() {
{name: "FlagLT_UGT"}, // signed < and unsigned >
{name: "FlagGT_UGT"}, // signed > and unsigned <
{name: "FlagGT_ULT"}, // signed > and unsigned >
// Special op for -x on 387
{name: "FCHS", argLength: 1, reg: fp11},
// Special ops for PIC floating-point constants.
// MOVSXconst1 loads the address of the constant-pool entry into a register.
// MOVSXconst2 loads the constant from that address.
// MOVSXconst1 returns a pointer, but we type it as uint32 because it can never point to the Go heap.
{name: "MOVSSconst1", reg: gp01, typ: "UInt32", aux: "Float32"},
{name: "MOVSDconst1", reg: gp01, typ: "UInt32", aux: "Float64"},
{name: "MOVSSconst2", argLength: 1, reg: gpfp, asm: "MOVSS"},
{name: "MOVSDconst2", argLength: 1, reg: gpfp, asm: "MOVSD"},
}
var _386blocks = []blockData{

63
src/cmd/compile/internal/ssa/opGen.go
View File

@ -345,6 +345,11 @@ const (
Op386FlagLT_UGT
Op386FlagGT_UGT
Op386FlagGT_ULT
Op386FCHS
Op386MOVSSconst1
Op386MOVSDconst1
Op386MOVSSconst2
Op386MOVSDconst2
OpAMD64ADDSS
OpAMD64ADDSD
@ -3675,6 +3680,64 @@ var opcodeTable = [...]opInfo{
argLen: 0,
reg: regInfo{},
},
{
name: "FCHS",
argLen: 1,
reg: regInfo{
inputs: []inputInfo{
{0, 65280}, // X0 X1 X2 X3 X4 X5 X6 X7
},
outputs: []outputInfo{
{0, 65280}, // X0 X1 X2 X3 X4 X5 X6 X7
},
},
},
{
name: "MOVSSconst1",
auxType: auxFloat32,
argLen: 0,
reg: regInfo{
outputs: []outputInfo{
{0, 239}, // AX CX DX BX BP SI DI
},
},
},
{
name: "MOVSDconst1",
auxType: auxFloat64,
argLen: 0,
reg: regInfo{
outputs: []outputInfo{
{0, 239}, // AX CX DX BX BP SI DI
},
},
},
{
name: "MOVSSconst2",
argLen: 1,
asm: x86.AMOVSS,
reg: regInfo{
inputs: []inputInfo{
{0, 239}, // AX CX DX BX BP SI DI
},
outputs: []outputInfo{
{0, 65280}, // X0 X1 X2 X3 X4 X5 X6 X7
},
},
},
{
name: "MOVSDconst2",
argLen: 1,
asm: x86.AMOVSD,
reg: regInfo{
inputs: []inputInfo{
{0, 239}, // AX CX DX BX BP SI DI
},
outputs: []outputInfo{
{0, 65280}, // X0 X1 X2 X3 X4 X5 X6 X7
},
},
},
{
name: "ADDSS",

78
src/cmd/compile/internal/ssa/rewrite386.go
View File

@ -78,6 +78,8 @@ func rewriteValue386(v *Value, config *Config) bool {
return rewriteValue386_Op386MOVLstoreidx1(v, config)
case Op386MOVLstoreidx4:
return rewriteValue386_Op386MOVLstoreidx4(v, config)
case Op386MOVSDconst:
return rewriteValue386_Op386MOVSDconst(v, config)
case Op386MOVSDload:
return rewriteValue386_Op386MOVSDload(v, config)
case Op386MOVSDloadidx1:
@ -90,6 +92,8 @@ func rewriteValue386(v *Value, config *Config) bool {
return rewriteValue386_Op386MOVSDstoreidx1(v, config)
case Op386MOVSDstoreidx8:
return rewriteValue386_Op386MOVSDstoreidx8(v, config)
case Op386MOVSSconst:
return rewriteValue386_Op386MOVSSconst(v, config)
case Op386MOVSSload:
return rewriteValue386_Op386MOVSSload(v, config)
case Op386MOVSSloadidx1:
@ -4213,6 +4217,25 @@ func rewriteValue386_Op386MOVLstoreidx4(v *Value, config *Config) bool {
}
return false
}
func rewriteValue386_Op386MOVSDconst(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (MOVSDconst [c])
// cond: config.ctxt.Flag_shared
// result: (MOVSDconst2 (MOVSDconst1 [c]))
for {
c := v.AuxInt
if !(config.ctxt.Flag_shared) {
break
}
v.reset(Op386MOVSDconst2)
v0 := b.NewValue0(v.Line, Op386MOVSDconst1, config.fe.TypeUInt32())
v0.AuxInt = c
v.AddArg(v0)
return true
}
return false
}
func rewriteValue386_Op386MOVSDload(v *Value, config *Config) bool {
b := v.Block
_ = b
@ -4683,6 +4706,25 @@ func rewriteValue386_Op386MOVSDstoreidx8(v *Value, config *Config) bool {
}
return false
}
func rewriteValue386_Op386MOVSSconst(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (MOVSSconst [c])
// cond: config.ctxt.Flag_shared
// result: (MOVSSconst2 (MOVSSconst1 [c]))
for {
c := v.AuxInt
if !(config.ctxt.Flag_shared) {
break
}
v.reset(Op386MOVSSconst2)
v0 := b.NewValue0(v.Line, Op386MOVSSconst1, config.fe.TypeUInt32())
v0.AuxInt = c
v.AddArg(v0)
return true
}
return false
}
func rewriteValue386_Op386MOVSSload(v *Value, config *Config) bool {
b := v.Block
_ = b
@ -11399,10 +11441,13 @@ func rewriteValue386_OpNeg32F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Neg32F x)
// cond:
// cond: !config.use387
// result: (PXOR x (MOVSSconst <config.Frontend().TypeFloat32()> [f2i(math.Copysign(0, -1))]))
for {
x := v.Args[0]
if !(!config.use387) {
break
}
v.reset(Op386PXOR)
v.AddArg(x)
v0 := b.NewValue0(v.Line, Op386MOVSSconst, config.Frontend().TypeFloat32())
@ -11410,15 +11455,31 @@ func rewriteValue386_OpNeg32F(v *Value, config *Config) bool {
v.AddArg(v0)
return true
}
// match: (Neg32F x)
// cond: config.use387
// result: (FCHS x)
for {
x := v.Args[0]
if !(config.use387) {
break
}
v.reset(Op386FCHS)
v.AddArg(x)
return true
}
return false
}
func rewriteValue386_OpNeg64F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Neg64F x)
// cond:
// cond: !config.use387
// result: (PXOR x (MOVSDconst <config.Frontend().TypeFloat64()> [f2i(math.Copysign(0, -1))]))
for {
x := v.Args[0]
if !(!config.use387) {
break
}
v.reset(Op386PXOR)
v.AddArg(x)
v0 := b.NewValue0(v.Line, Op386MOVSDconst, config.Frontend().TypeFloat64())
@ -11426,6 +11487,19 @@ func rewriteValue386_OpNeg64F(v *Value, config *Config) bool {
v.AddArg(v0)
return true
}
// match: (Neg64F x)
// cond: config.use387
// result: (FCHS x)
for {
x := v.Args[0]
if !(config.use387) {
break
}
v.reset(Op386FCHS)
v.AddArg(x)
return true
}
return false
}
func rewriteValue386_OpNeg8(v *Value, config *Config) bool {
b := v.Block

27
src/cmd/compile/internal/x86/387.go
View File

@ -29,6 +29,14 @@ func ssaGenValue387(s *gc.SSAGenState, v *ssa.Value) bool {
p.To.Reg = x86.REG_F0
popAndSave(s, v)
return true
case ssa.Op386MOVSSconst2, ssa.Op386MOVSDconst2:
p := gc.Prog(loadPush(v.Type))
p.From.Type = obj.TYPE_MEM
p.From.Reg = gc.SSARegNum(v.Args[0])
p.To.Type = obj.TYPE_REG
p.To.Reg = x86.REG_F0
popAndSave(s, v)
return true
case ssa.Op386MOVSSload, ssa.Op386MOVSDload, ssa.Op386MOVSSloadidx1, ssa.Op386MOVSDloadidx1, ssa.Op386MOVSSloadidx4, ssa.Op386MOVSDloadidx8:
p := gc.Prog(loadPush(v.Type))
@ -183,28 +191,11 @@ func ssaGenValue387(s *gc.SSAGenState, v *ssa.Value) bool {
popAndSave(s, v)
return true
case ssa.Op386PXOR:
a0 := v.Args[0]
a1 := v.Args[1]
for a0.Op == ssa.OpCopy {
a0 = a0.Args[0]
}
for a1.Op == ssa.OpCopy {
a1 = a1.Args[0]
}
if (a0.Op == ssa.Op386MOVSSconst || a0.Op == ssa.Op386MOVSDconst) && a0.AuxInt == -0x8000000000000000 {
push(s, v.Args[1])
gc.Prog(x86.AFCHS)
popAndSave(s, v)
return true
}
if (a1.Op == ssa.Op386MOVSSconst || a1.Op == ssa.Op386MOVSDconst) && a1.AuxInt == -0x8000000000000000 {
case ssa.Op386FCHS:
push(s, v.Args[0])
gc.Prog(x86.AFCHS)
popAndSave(s, v)
return true
}
v.Fatalf("PXOR not used to change sign %s", v.LongString())
case ssa.Op386CVTSL2SS, ssa.Op386CVTSL2SD:
p := gc.Prog(x86.AMOVL)

23
src/cmd/compile/internal/x86/ssa.go
View File

@ -456,6 +456,27 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
p.From.Val = math.Float64frombits(uint64(v.AuxInt))
p.To.Type = obj.TYPE_REG
p.To.Reg = x
case ssa.Op386MOVSSconst1, ssa.Op386MOVSDconst1:
var literal string
if v.Op == ssa.Op386MOVSDconst1 {
literal = fmt.Sprintf("$f64.%016x", uint64(v.AuxInt))
} else {
literal = fmt.Sprintf("$f32.%08x", math.Float32bits(float32(math.Float64frombits(uint64(v.AuxInt)))))
}
p := gc.Prog(x86.ALEAL)
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_EXTERN
p.From.Sym = obj.Linklookup(gc.Ctxt, literal, 0)
p.From.Sym.Local = true
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386MOVSSconst2, ssa.Op386MOVSDconst2:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_MEM
p.From.Reg = gc.SSARegNum(v.Args[0])
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386MOVSSload, ssa.Op386MOVSDload, ssa.Op386MOVLload, ssa.Op386MOVWload, ssa.Op386MOVBload, ssa.Op386MOVBLSXload, ssa.Op386MOVWLSXload:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_MEM
@ -872,6 +893,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
if gc.Debug_checknil != 0 && v.Line > 1 { // v.Line==1 in generated wrappers
gc.Warnl(v.Line, "generated nil check")
}
case ssa.Op386FCHS:
v.Fatalf("FCHS in non-387 mode")
default:
v.Unimplementedf("genValue not implemented: %s", v.LongString())
}