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cmd/compile: defer lowering OANDNOT until SSA

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Currently, "x &^ y" gets rewriten into "x & ^y" during walk. It adds
unnecessary complexity to other parts, which must aware about this.

Instead, we can just implement "&^" in the conversion to SSA, so "&^"
can be handled like other binary operators.

However, this CL does not pass toolstash-check. It seems that implements
"&^" in the conversion to SSA causes registers allocation change.

With the parent:

obj: 00212 (.../src/runtime/complex.go:47)    MOVQ    X0, AX
obj: 00213 (.../src/runtime/complex.go:47)    BTRQ    $63, AX
obj: 00214 (.../src/runtime/complex.go:47)    MOVQ    "".n(SP), CX
obj: 00215 (.../src/runtime/complex.go:47)    MOVQ    $-9223372036854775808, DX
obj: 00216 (.../src/runtime/complex.go:47)    ANDQ    DX, CX
obj: 00217 (.../src/runtime/complex.go:47)    ORQ AX, CX

With this CL:

obj: 00212 (.../src/runtime/complex.go:47)    MOVQ    X0, AX
obj: 00213 (.../src/runtime/complex.go:47)    BTRQ    $63, AX
obj: 00214 (.../src/runtime/complex.go:47)    MOVQ    $-9223372036854775808, CX
obj: 00215 (.../src/runtime/complex.go:47)    MOVQ    "".n(SP), DX
obj: 00216 (.../src/runtime/complex.go:47)    ANDQ    CX, DX
obj: 00217 (.../src/runtime/complex.go:47)    ORQ AX, DX

Change-Id: I80acf8496a91be4804fb7ef3df04c19baae2754c
Reviewed-on: https://go-review.googlesource.com/c/go/+/264660
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Cuong Manh Le 2020-10-24 10:40:09 +07:00
parent fb7134e4e3
commit a19cf510af
4 changed files with 23 additions and 19 deletions
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5
src/cmd/compile/internal/gc/ssa.go
View file

@ -2472,6 +2472,11 @@ func (s *state) expr(n *Node) *ssa.Value {
a := s.expr(n.Left)
b := s.expr(n.Right)
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case OANDNOT:
a := s.expr(n.Left)
b := s.expr(n.Right)
b = s.newValue1(s.ssaOp(OBITNOT, b.Type), b.Type, b)
return s.newValue2(s.ssaOp(OAND, n.Type), a.Type, a, b)
case OLSH, ORSH:
a := s.expr(n.Left)
b := s.expr(n.Right)