[dev.ssa] cmd/compile: fix fp constant loads for 386+PIC
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>
diff --git a/src/cmd/compile/internal/ssa/gen/386.rules b/src/cmd/compile/internal/ssa/gen/386.rules
index b360189..0609d3b 100644
--- a/src/cmd/compile/internal/ssa/gen/386.rules
+++ b/src/cmd/compile/internal/ssa/gen/386.rules
@@ -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]))
diff --git a/src/cmd/compile/internal/ssa/gen/386Ops.go b/src/cmd/compile/internal/ssa/gen/386Ops.go
index 86f6f72..1013adf 100644
--- a/src/cmd/compile/internal/ssa/gen/386Ops.go
+++ b/src/cmd/compile/internal/ssa/gen/386Ops.go
@@ -463,6 +463,18 @@
{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{
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 38a2ba7..75381c4 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -345,6 +345,11 @@
Op386FlagLT_UGT
Op386FlagGT_UGT
Op386FlagGT_ULT
+ Op386FCHS
+ Op386MOVSSconst1
+ Op386MOVSDconst1
+ Op386MOVSSconst2
+ Op386MOVSDconst2
OpAMD64ADDSS
OpAMD64ADDSD
@@ -3675,6 +3680,64 @@
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",
diff --git a/src/cmd/compile/internal/ssa/rewrite386.go b/src/cmd/compile/internal/ssa/rewrite386.go
index caccf88..b791c44 100644
--- a/src/cmd/compile/internal/ssa/rewrite386.go
+++ b/src/cmd/compile/internal/ssa/rewrite386.go
@@ -78,6 +78,8 @@
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 @@
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 @@
}
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 @@
}
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 @@
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 @@
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 @@
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
diff --git a/src/cmd/compile/internal/x86/387.go b/src/cmd/compile/internal/x86/387.go
index 96a7d63..bd0971c 100644
--- a/src/cmd/compile/internal/x86/387.go
+++ b/src/cmd/compile/internal/x86/387.go
@@ -29,6 +29,14 @@
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 @@
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 {
- 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.Op386FCHS:
+ push(s, v.Args[0])
+ gc.Prog(x86.AFCHS)
+ popAndSave(s, v)
+ return true
case ssa.Op386CVTSL2SS, ssa.Op386CVTSL2SD:
p := gc.Prog(x86.AMOVL)
diff --git a/src/cmd/compile/internal/x86/ssa.go b/src/cmd/compile/internal/x86/ssa.go
index e941e6c..3005a19 100644
--- a/src/cmd/compile/internal/x86/ssa.go
+++ b/src/cmd/compile/internal/x86/ssa.go
@@ -456,6 +456,27 @@
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 @@
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())
}
