mirror of
https://github.com/golang/go.git
synced 2025-12-08 06:10:04 +00:00
cmd/compile: define high bits of AuxInt
Previously if we were only using the low bits of AuxInt, the high bits were ignored and could be junk. This CL changes that behavior to define the high bits to be the sign-extended version of the low bits for all cases. There are 2 main benefits: - Deterministic representation. This helps with CSE. (Const8 [0x1]) and (Const8 [0x101]) used to be the same "value" but CSE couldn't see them as such. - Testability. We can check that all ops leave AuxInt in a state consistent with the new rule. In the old scheme, it was hard to check whether a rule correctly used only the low-order bits. Side benefits: - ==0 and !=0 tests are easier. Drawbacks: - This differs from the runtime representation in registers, where it is important that we allow upper bits to be undefined (so we're not sign/zero-extending all the time). - Ops that treat AuxInt as unsigned (shifts, mostly) need to be a bit more careful. Change-Id: I9a685ff27e36dc03287c9ab1cecd6c0b4045c819 Reviewed-on: https://go-review.googlesource.com/21256 Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This commit is contained in:
Keith Randall
parent
18072adbca
commit
7fc5621991
11 changed files with 392 additions and 391 deletions
|
|
@ -420,7 +420,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
r := gc.SSARegNum(v)
|
||||
a := gc.SSARegNum(v.Args[0])
|
||||
if r == a {
|
||||
if v.AuxInt2Int64() == 1 {
|
||||
if v.AuxInt == 1 {
|
||||
var asm obj.As
|
||||
switch v.Op {
|
||||
// Software optimization manual recommends add $1,reg.
|
||||
|
|
@ -439,7 +439,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = r
|
||||
return
|
||||
} else if v.AuxInt2Int64() == -1 {
|
||||
} else if v.AuxInt == -1 {
|
||||
var asm obj.As
|
||||
switch v.Op {
|
||||
case ssa.OpAMD64ADDQconst:
|
||||
|
|
@ -456,7 +456,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
} else {
|
||||
p := gc.Prog(v.Op.Asm())
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
p.From.Offset = v.AuxInt2Int64()
|
||||
p.From.Offset = v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = r
|
||||
return
|
||||
|
|
@ -474,7 +474,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
p := gc.Prog(asm)
|
||||
p.From.Type = obj.TYPE_MEM
|
||||
p.From.Reg = a
|
||||
p.From.Offset = v.AuxInt2Int64()
|
||||
p.From.Offset = v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = r
|
||||
|
||||
|
|
@ -494,7 +494,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
// Constant into AX, after arg0 movement in case arg0 is in AX
|
||||
p := gc.Prog(moveByType(v.Type))
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
p.From.Offset = v.AuxInt2Int64()
|
||||
p.From.Offset = v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = x86.REG_AX
|
||||
|
||||
|
|
@ -516,7 +516,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
}
|
||||
p := gc.Prog(v.Op.Asm())
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
p.From.Offset = v.AuxInt2Int64()
|
||||
p.From.Offset = v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = r
|
||||
// TODO: Teach doasm to compile the three-address multiply imul $c, r1, r2
|
||||
|
|
@ -531,7 +531,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
// a = b + (- const), saves us 1 instruction. We can't fit
|
||||
// - (-1 << 31) into 4 bytes offset in lea.
|
||||
// We handle 2-address just fine below.
|
||||
if v.AuxInt2Int64() == -1<<31 || x == r {
|
||||
if v.AuxInt == -1<<31 || x == r {
|
||||
if x != r {
|
||||
// This code compensates for the fact that the register allocator
|
||||
// doesn't understand 2-address instructions yet. TODO: fix that.
|
||||
|
|
@ -543,10 +543,10 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
}
|
||||
p := gc.Prog(v.Op.Asm())
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
p.From.Offset = v.AuxInt2Int64()
|
||||
p.From.Offset = v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = r
|
||||
} else if x == r && v.AuxInt2Int64() == -1 {
|
||||
} else if x == r && v.AuxInt == -1 {
|
||||
var asm obj.As
|
||||
// x = x - (-1) is the same as x++
|
||||
// See OpAMD64ADDQconst comments about inc vs add $1,reg
|
||||
|
|
@ -561,7 +561,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
p := gc.Prog(asm)
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = r
|
||||
} else if x == r && v.AuxInt2Int64() == 1 {
|
||||
} else if x == r && v.AuxInt == 1 {
|
||||
var asm obj.As
|
||||
switch v.Op {
|
||||
case ssa.OpAMD64SUBQconst:
|
||||
|
|
@ -587,7 +587,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
p := gc.Prog(asm)
|
||||
p.From.Type = obj.TYPE_MEM
|
||||
p.From.Reg = x
|
||||
p.From.Offset = -v.AuxInt2Int64()
|
||||
p.From.Offset = -v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = r
|
||||
}
|
||||
|
|
@ -614,7 +614,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
}
|
||||
p := gc.Prog(v.Op.Asm())
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
p.From.Offset = v.AuxInt2Int64()
|
||||
p.From.Offset = v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = r
|
||||
case ssa.OpAMD64SBBQcarrymask, ssa.OpAMD64SBBLcarrymask:
|
||||
|
|
@ -661,18 +661,18 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
p.From.Type = obj.TYPE_REG
|
||||
p.From.Reg = gc.SSARegNum(v.Args[0])
|
||||
p.To.Type = obj.TYPE_CONST
|
||||
p.To.Offset = v.AuxInt2Int64()
|
||||
p.To.Offset = v.AuxInt
|
||||
case ssa.OpAMD64TESTQconst, ssa.OpAMD64TESTLconst, ssa.OpAMD64TESTWconst, ssa.OpAMD64TESTBconst:
|
||||
p := gc.Prog(v.Op.Asm())
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
p.From.Offset = v.AuxInt2Int64()
|
||||
p.From.Offset = v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = gc.SSARegNum(v.Args[0])
|
||||
case ssa.OpAMD64MOVBconst, ssa.OpAMD64MOVWconst, ssa.OpAMD64MOVLconst, ssa.OpAMD64MOVQconst:
|
||||
x := gc.SSARegNum(v)
|
||||
p := gc.Prog(v.Op.Asm())
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
p.From.Offset = v.AuxInt2Int64()
|
||||
p.From.Offset = v.AuxInt
|
||||
p.To.Type = obj.TYPE_REG
|
||||
p.To.Reg = x
|
||||
// If flags are live at this instruction, suppress the
|
||||
|
|
@ -804,17 +804,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
p := gc.Prog(v.Op.Asm())
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
sc := v.AuxValAndOff()
|
||||
i := sc.Val()
|
||||
switch v.Op {
|
||||
case ssa.OpAMD64MOVBstoreconst:
|
||||
i = int64(int8(i))
|
||||
case ssa.OpAMD64MOVWstoreconst:
|
||||
i = int64(int16(i))
|
||||
case ssa.OpAMD64MOVLstoreconst:
|
||||
i = int64(int32(i))
|
||||
case ssa.OpAMD64MOVQstoreconst:
|
||||
}
|
||||
p.From.Offset = i
|
||||
p.From.Offset = sc.Val()
|
||||
p.To.Type = obj.TYPE_MEM
|
||||
p.To.Reg = gc.SSARegNum(v.Args[0])
|
||||
gc.AddAux2(&p.To, v, sc.Off())
|
||||
|
|
@ -822,18 +812,15 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
|
|||
p := gc.Prog(v.Op.Asm())
|
||||
p.From.Type = obj.TYPE_CONST
|
||||
sc := v.AuxValAndOff()
|
||||
p.From.Offset = sc.Val()
|
||||
switch v.Op {
|
||||
case ssa.OpAMD64MOVBstoreconstidx1:
|
||||
p.From.Offset = int64(int8(sc.Val()))
|
||||
p.To.Scale = 1
|
||||
case ssa.OpAMD64MOVWstoreconstidx2:
|
||||
p.From.Offset = int64(int16(sc.Val()))
|
||||
p.To.Scale = 2
|
||||
case ssa.OpAMD64MOVLstoreconstidx4:
|
||||
p.From.Offset = int64(int32(sc.Val()))
|
||||
p.To.Scale = 4
|
||||
case ssa.OpAMD64MOVQstoreconstidx8:
|
||||
p.From.Offset = sc.Val()
|
||||
p.To.Scale = 8
|
||||
}
|
||||
p.To.Type = obj.TYPE_MEM
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue