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cmd/compile/internal/s390x: replace 4-byte NOP with a 2-byte NOP on s390x

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Added a new instruction, NOPH, with the encoding [0x0700](i.e: bcr 0, 0) and
replace the current 4-byte nop that was encoded using the WORD instruction.

This reduces the size of .text section in go binary by around 17KB and make
generated code easier to read.

Change-Id: I6a756df39e93c4415ea6d038ba4af001b8ccb286
Reviewed-on: https://go-review.googlesource.com/c/go/+/194344
Reviewed-by: Michael Munday <mike.munday@ibm.com>
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Ruixin(Peter) Bao 2019-08-22 09:53:54 -04:00 committed by Michael Munday
parent b25ec50b69
commit 11c2411c50
5 changed files with 13 additions and 4 deletions
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3
src/cmd/asm/internal/asm/testdata/s390x.s vendored
View File

@ -329,6 +329,9 @@ TEXT main·foo(SB),DUPOK|NOSPLIT,$16-0 // TEXT main.foo(SB), DUPOK|NOSPLIT, $16-
TCEB F5, $8 // ed5000080010
TCDB F15, $4095 // edf00fff0011
UNDEF // 00000000
NOPH // 0700
VL (R15), V1 // e710f0000006
VST V1, (R15) // e710f000000e
VL (R15), V31 // e7f0f0000806

5
src/cmd/compile/internal/s390x/ggen.go
View File

@ -105,8 +105,5 @@ func zeroAuto(pp *gc.Progs, n *gc.Node) {
}
func ginsnop(pp *gc.Progs) *obj.Prog {
p := pp.Prog(s390x.AWORD)
p.From.Type = obj.TYPE_CONST
p.From.Offset = 0x47000000 // nop 0
return p
return pp.Prog(s390x.ANOPH)
}

2
src/cmd/internal/obj/s390x/a.out.go
View File

@ -966,6 +966,8 @@ const (
AVMSLOG
AVMSLEOG
ANOPH // NOP
// binary
ABYTE
AWORD

1
src/cmd/internal/obj/s390x/anames.go
View File

@ -696,6 +696,7 @@ var Anames = []string{
"VMSLEG",
"VMSLOG",
"VMSLEOG",
"NOPH",
"BYTE",
"WORD",
"DWORD",

6
src/cmd/internal/obj/s390x/asmz.go
View File

@ -314,6 +314,9 @@ var optab = []Optab{
// undefined (deliberate illegal instruction)
{i: 78, as: obj.AUNDEF},
// 2 byte no-operation
{i: 66, as: ANOPH},
// vector instructions
// VRX store
@ -3394,6 +3397,9 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
d2 := c.regoff(&p.To)
zRXE(opcode, uint32(p.From.Reg), 0, 0, uint32(d2), 0, asm)
case 66:
zRR(op_BCR, 0, 0, asm)
case 67: // fmov $0 freg
var opcode uint32
switch p.As {