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cmd/compile: fix incorrect truncating when converting CMP to TST on arm64 

CL 420434 optimized CMP into TST in some situations, but it has a bug,
these four rules are not correct:
(LessThan (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (LessThan (TSTconst [c] y))
(LessEqual (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (LessEqual (TSTconst [c] y))
(GreaterThan (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (GreaterThan (TSTconst [c] y))
(GreaterEqual (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (GreaterEqual (TSTconst [c] y))

But due to the existence of this rule
(LessThan (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 =>
(LessThan (TSTWconst [int32(c)] y)), the above rules have never been
fired. This CL corrects them as:
(LessThan (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (LessThan (TSTconst [c] y))
(LessEqual (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (LessEqual (TSTconst [c] y))
(GreaterThan (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (GreaterThan (TSTconst [c] y))
(GreaterEqual (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (GreaterEqual (TSTconst [c] y))

Change-Id: I7d60bcc9a266ee58388baeaab9f493b57cf1ad55
Reviewed-on: https://go-review.googlesource.com/c/go/+/473617
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Eric Fang <eric.fang@arm.com>
This commit is contained in:
erifan01 2023-03-07 08:44:08 +08:00 committed by Eric Fang
parent ed2442a0e1
commit 91a2e921dd
3 changed files with 16 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/cmd/compile/internal/ssa/_gen/ARM64.rules
View File

@ -706,10 +706,10 @@
(Equal (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (Equal (TSTconst [c] y))
(NotEqual (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (NotEqual (TSTconst [c] y))
(LessThan (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (LessThan (TSTconst [c] y))
(LessEqual (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (LessEqual (TSTconst [c] y))
(GreaterThan (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (GreaterThan (TSTconst [c] y))
(GreaterEqual (CMPWconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (GreaterEqual (TSTconst [c] y))
(LessThan (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (LessThan (TSTconst [c] y))
(LessEqual (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (LessEqual (TSTconst [c] y))
(GreaterThan (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (GreaterThan (TSTconst [c] y))
(GreaterEqual (CMPconst [0] x:(ANDconst [c] y))) && x.Uses == 1 => (GreaterEqual (TSTconst [c] y))
(EQ (CMPconst [0] x:(ADDconst [c] y)) yes no) && x.Uses == 1 => (EQ (CMNconst [c] y) yes no)
(NE (CMPconst [0] x:(ADDconst [c] y)) yes no) && x.Uses == 1 => (NE (CMNconst [c] y) yes no)

16
src/cmd/compile/internal/ssa/rewriteARM64.go
View File

@ -5698,11 +5698,11 @@ func rewriteValueARM64_OpARM64GreaterEqual(v *Value) bool {
v.AddArg(v0)
return true
}
// match: (GreaterEqual (CMPWconst [0] x:(ANDconst [c] y)))
// match: (GreaterEqual (CMPconst [0] x:(ANDconst [c] y)))
// cond: x.Uses == 1
// result: (GreaterEqual (TSTconst [c] y))
for {
if v_0.Op != OpARM64CMPWconst || auxIntToInt32(v_0.AuxInt) != 0 {
if v_0.Op != OpARM64CMPconst || auxIntToInt64(v_0.AuxInt) != 0 {
break
}
x := v_0.Args[0]
@ -5856,11 +5856,11 @@ func rewriteValueARM64_OpARM64GreaterThan(v *Value) bool {
v.AddArg(v0)
return true
}
// match: (GreaterThan (CMPWconst [0] x:(ANDconst [c] y)))
// match: (GreaterThan (CMPconst [0] x:(ANDconst [c] y)))
// cond: x.Uses == 1
// result: (GreaterThan (TSTconst [c] y))
for {
if v_0.Op != OpARM64CMPWconst || auxIntToInt32(v_0.AuxInt) != 0 {
if v_0.Op != OpARM64CMPconst || auxIntToInt64(v_0.AuxInt) != 0 {
break
}
x := v_0.Args[0]
@ -6064,11 +6064,11 @@ func rewriteValueARM64_OpARM64LessEqual(v *Value) bool {
v.AddArg(v0)
return true
}
// match: (LessEqual (CMPWconst [0] x:(ANDconst [c] y)))
// match: (LessEqual (CMPconst [0] x:(ANDconst [c] y)))
// cond: x.Uses == 1
// result: (LessEqual (TSTconst [c] y))
for {
if v_0.Op != OpARM64CMPWconst || auxIntToInt32(v_0.AuxInt) != 0 {
if v_0.Op != OpARM64CMPconst || auxIntToInt64(v_0.AuxInt) != 0 {
break
}
x := v_0.Args[0]
@ -6222,11 +6222,11 @@ func rewriteValueARM64_OpARM64LessThan(v *Value) bool {
v.AddArg(v0)
return true
}
// match: (LessThan (CMPWconst [0] x:(ANDconst [c] y)))
// match: (LessThan (CMPconst [0] x:(ANDconst [c] y)))
// cond: x.Uses == 1
// result: (LessThan (TSTconst [c] y))
for {
if v_0.Op != OpARM64CMPWconst || auxIntToInt32(v_0.AuxInt) != 0 {
if v_0.Op != OpARM64CMPconst || auxIntToInt64(v_0.AuxInt) != 0 {
break
}
x := v_0.Args[0]

4
test/codegen/comparisons.go
View File

@ -234,6 +234,8 @@ func CmpToZero(a, b, d int32, e, f int64, deOptC0, deOptC1 bool) int32 {
c7 := e&(f<<3) < 0
// arm64:`CMN\sR[0-9]+<<3,\sR[0-9]+`
c8 := e+(f<<3) < 0
// arm64:`TST\sR[0-9],\sR[0-9]+`
c9 := e&17 < 0
if c0 {
return 1
} else if c1 {
@ -252,6 +254,8 @@ func CmpToZero(a, b, d int32, e, f int64, deOptC0, deOptC1 bool) int32 {
return 9
} else if c8 {
return 10
} else if c9 {
return 11
} else if deOptC0 {
return b + d
} else if deOptC1 {