qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-14 09:00:21 -07:00
Code Releases Activity

cmd/compile: fix FP accuracy issue introduced by FMA optimization on ARM64

Browse Source 
Two ARM64 rules are added to avoid FP accuracy issue, which causes
build failure.
https://build.golang.org/log/1360f5c9ef3f37968216350283c1013e9681725d

fixes #24033

Change-Id: I9b74b584ab5cc53fa49476de275dc549adf97610
Reviewed-on: https://go-review.googlesource.com/96355
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Ben Shi 2018-02-22 13:55:01 +00:00 committed by Cherry Zhang
parent ef3ab3f5e2
commit 7113d3a512
5 changed files with 38 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/cmd/compile/internal/arm64/ssa.go
View File

@ -590,6 +590,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
p.From.Reg = v.Args[0].Reg()
p.To.Type = obj.TYPE_REG
p.To.Reg = v.Reg()
case ssa.OpARM64LoweredRound32F, ssa.OpARM64LoweredRound64F:
// input is already rounded
case ssa.OpARM64VCNT:
p := s.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG

4
src/cmd/compile/internal/ssa/gen/ARM64.rules
View File

@ -237,8 +237,8 @@
(Cvt32Fto64F x) -> (FCVTSD x)
(Cvt64Fto32F x) -> (FCVTDS x)
(Round32F x) -> x
(Round64F x) -> x
(Round32F x) -> (LoweredRound32F x)
(Round64F x) -> (LoweredRound64F x)
// comparisons
(Eq8 x y) -> (Equal (CMPW (ZeroExt8to32 x) (ZeroExt8to32 y)))

2
src/cmd/compile/internal/ssa/gen/ARM64Ops.go
View File

@ -216,6 +216,8 @@ func init() {
{name: "CLZW", argLength: 1, reg: gp11, asm: "CLZW"}, // count leading zero, 32-bit
{name: "VCNT", argLength: 1, reg: fp11, asm: "VCNT"}, // count set bits for each 8-bit unit and store the result in each 8-bit unit
{name: "VUADDLV", argLength: 1, reg: fp11, asm: "VUADDLV"}, // unsigned sum of eight bytes in a 64-bit value, zero extended to 64-bit.
{name: "LoweredRound32F", argLength: 1, reg: fp11, resultInArg0: true},
{name: "LoweredRound64F", argLength: 1, reg: fp11, resultInArg0: true},
// 3-operand, the addend comes first
{name: "FMADDS", argLength: 3, reg: fp31, asm: "FMADDS"}, // +arg0 + (arg1 * arg2)

28
src/cmd/compile/internal/ssa/opGen.go
View File

@ -1003,6 +1003,8 @@ const (
OpARM64CLZW
OpARM64VCNT
OpARM64VUADDLV
OpARM64LoweredRound32F
OpARM64LoweredRound64F
OpARM64FMADDS
OpARM64FMADDD
OpARM64FNMADDS
@ -12765,6 +12767,32 @@ var opcodeTable = [...]opInfo{
},
},
},
{
name: "LoweredRound32F",
argLen: 1,
resultInArg0: true,
reg: regInfo{
inputs: []inputInfo{
{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
},
outputs: []outputInfo{
{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
},
},
},
{
name: "LoweredRound64F",
argLen: 1,
resultInArg0: true,
reg: regInfo{
inputs: []inputInfo{
{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
},
outputs: []outputInfo{
{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
},
},
},
{
name: "FMADDS",
argLen: 3,

10
src/cmd/compile/internal/ssa/rewriteARM64.go
View File

@ -16318,11 +16318,10 @@ func rewriteValueARM64_OpRound_0(v *Value) bool {
func rewriteValueARM64_OpRound32F_0(v *Value) bool {
// match: (Round32F x)
// cond:
// result: x
// result: (LoweredRound32F x)
for {
x := v.Args[0]
v.reset(OpCopy)
v.Type = x.Type
v.reset(OpARM64LoweredRound32F)
v.AddArg(x)
return true
}
@ -16330,11 +16329,10 @@ func rewriteValueARM64_OpRound32F_0(v *Value) bool {
func rewriteValueARM64_OpRound64F_0(v *Value) bool {
// match: (Round64F x)
// cond:
// result: x
// result: (LoweredRound64F x)
for {
x := v.Args[0]
v.reset(OpCopy)
v.Type = x.Type
v.reset(OpARM64LoweredRound64F)
v.AddArg(x)
return true
}