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cmd/internal/obj/arm64: materialize float constant 0 from zero register 

Materialize float constant 0 from integer zero register, instead
of loading from constant pool.

Also fix assembling FMOV from zero register to FP register.

Change-Id: Ie413dd342cedebdb95ba8cfc220e23ed2a39e885
Reviewed-on: https://go-review.googlesource.com/32250
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Cherry Zhang 2016-10-26 18:10:40 -04:00
parent 9d1efba28d
commit a866df2671
2 changed files with 14 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/cmd/internal/obj/arm64/asm7.go
View File

@ -2380,13 +2380,15 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
o2 |= uint32(p.To.Reg & 31)
case 29: /* op Rn, Rd */
if (p.As == AFMOVD || p.As == AFMOVS) && (aclass(ctxt, &p.From) == C_REG || aclass(ctxt, &p.To) == C_REG) {
fc := aclass(ctxt, &p.From)
tc := aclass(ctxt, &p.To)
if (p.As == AFMOVD || p.As == AFMOVS) && (fc == C_REG || fc == C_ZCON || tc == C_REG || tc == C_ZCON) {
// FMOV Rx, Fy or FMOV Fy, Rx
o1 = FPCVTI(0, 0, 0, 0, 6)
if p.As == AFMOVD {
o1 |= 1<<31 | 1<<22 // 64-bit
}
if aclass(ctxt, &p.From) == C_REG {
if fc == C_REG || fc == C_ZCON {
o1 |= 1 << 16 // FMOV Rx, Fy
}
} else {

10
src/cmd/internal/obj/arm64/obj7.go
View File

@ -262,6 +262,11 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
if p.From.Type == obj.TYPE_FCONST {
f32 := float32(p.From.Val.(float64))
i32 := math.Float32bits(f32)
if i32 == 0 {
p.From.Type = obj.TYPE_REG
p.From.Reg = REGZERO
break
}
literal := fmt.Sprintf("$f32.%08x", i32)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 4
@ -275,6 +280,11 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
case AFMOVD:
if p.From.Type == obj.TYPE_FCONST {
i64 := math.Float64bits(p.From.Val.(float64))
if i64 == 0 {
p.From.Type = obj.TYPE_REG
p.From.Reg = REGZERO
break
}
literal := fmt.Sprintf("$f64.%016x", i64)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 8