Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

cmd/compile: add intrinsics for runtime/internal/math on 386 and amd64

Browse source 
Add generic, 386 and amd64 specific ops and SSA rules for multiplication
with overflow and branching based on overflow flags. Use these to intrinsify
runtime/internal/math.MulUinptr.

On amd64
  mul, overflow := math.MulUintptr(a, b)
  if overflow {
is lowered to two instructions:
  MULQ SI
  JO 0x10ee35c

No codegen tests as codegen can not currently test unexported internal runtime
functions.

amd64:
name              old time/op  new time/op  delta
MulUintptr/small  1.16ns ± 5%  0.88ns ± 6%  -24.36%  (p=0.000 n=19+20)
MulUintptr/large  10.7ns ± 1%   1.1ns ± 1%  -89.28%  (p=0.000 n=17+19)

Change-Id: If60739a86f820e5044d677276c21df90d3c7a86a
Reviewed-on: https://go-review.googlesource.com/c/141820
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Martin Möhrmann 2018-01-27 11:55:34 +01:00
parent 9f66b41bee
commit a1ca4893ff
12 changed files with 459 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

13
src/cmd/compile/internal/x86/ssa.go
View file

@ -278,6 +278,13 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
m.To.Reg = x86.REG_DX
}
case ssa.Op386MULLU:
// Arg[0] is already in AX as it's the only register we allow
// results lo in AX
p := s.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = v.Args[1].Reg()
case ssa.Op386MULLQU:
// AX * args[1], high 32 bits in DX (result[0]), low 32 bits in AX (result[1]).
p := s.Prog(v.Op.Asm())
@ -770,7 +777,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
ssa.Op386SETGF, ssa.Op386SETGEF,
ssa.Op386SETB, ssa.Op386SETBE,
ssa.Op386SETORD, ssa.Op386SETNAN,
ssa.Op386SETA, ssa.Op386SETAE:
ssa.Op386SETA, ssa.Op386SETAE,
ssa.Op386SETO:
p := s.Prog(v.Op.Asm())
p.To.Type = obj.TYPE_REG
p.To.Reg = v.Reg()
@ -842,6 +850,8 @@ var blockJump = [...]struct {
ssa.Block386GE: {x86.AJGE, x86.AJLT},
ssa.Block386LE: {x86.AJLE, x86.AJGT},
ssa.Block386GT: {x86.AJGT, x86.AJLE},
ssa.Block386OS: {x86.AJOS, x86.AJOC},
ssa.Block386OC: {x86.AJOC, x86.AJOS},
ssa.Block386ULT: {x86.AJCS, x86.AJCC},
ssa.Block386UGE: {x86.AJCC, x86.AJCS},
ssa.Block386UGT: {x86.AJHI, x86.AJLS},
@ -903,6 +913,7 @@ func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
case ssa.Block386EQ, ssa.Block386NE,
ssa.Block386LT, ssa.Block386GE,
ssa.Block386LE, ssa.Block386GT,
ssa.Block386OS, ssa.Block386OC,
ssa.Block386ULT, ssa.Block386UGT,
ssa.Block386ULE, ssa.Block386UGE:
jmp := blockJump[b.Kind]