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author | Cuong Manh Le <cuong.manhle.vn@gmail.com> | 2020-10-24 10:40:09 +0700 |
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committer | Cuong Manh Le <cuong.manhle.vn@gmail.com> | 2020-10-27 03:11:45 +0000 |
commit | a19cf510af8182751fefc16ce962f91fe17c1e1b (patch) | |
tree | 20e7b93b381a5ce33e088748be8a90fd04e06462 | |
parent | fb7134e4e3a45fee4ab662ef0d467ef864c23e2e (diff) | |
download | go-a19cf510af8182751fefc16ce962f91fe17c1e1b.tar.gz go-a19cf510af8182751fefc16ce962f91fe17c1e1b.zip |
cmd/compile: defer lowering OANDNOT until SSA
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>
-rw-r--r-- | src/cmd/compile/internal/gc/ssa.go | 5 | ||||
-rw-r--r-- | src/cmd/compile/internal/gc/syntax.go | 2 | ||||
-rw-r--r-- | src/cmd/compile/internal/gc/walk.go | 30 | ||||
-rw-r--r-- | test/bounds.go | 5 |
4 files changed, 23 insertions, 19 deletions
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go index a1b5a03687..4769c2c7d9 100644 --- a/src/cmd/compile/internal/gc/ssa.go +++ b/src/cmd/compile/internal/gc/ssa.go @@ -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) diff --git a/src/cmd/compile/internal/gc/syntax.go b/src/cmd/compile/internal/gc/syntax.go index 83b5db834f..58de9b5e3f 100644 --- a/src/cmd/compile/internal/gc/syntax.go +++ b/src/cmd/compile/internal/gc/syntax.go @@ -142,7 +142,7 @@ const ( _, _ // second nodeInitorder bit _, nodeHasBreak _, nodeNoInline // used internally by inliner to indicate that a function call should not be inlined; set for OCALLFUNC and OCALLMETH only - _, nodeImplicit // implicit OADDR or ODEREF; ++/-- statement represented as OASOP; or ANDNOT lowered to OAND + _, nodeImplicit // implicit OADDR or ODEREF; ++/-- statement represented as OASOP _, nodeIsDDD // is the argument variadic _, nodeDiag // already printed error about this _, nodeColas // OAS resulting from := diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go index 6ce3eda44b..927f6c4b1e 100644 --- a/src/cmd/compile/internal/gc/walk.go +++ b/src/cmd/compile/internal/gc/walk.go @@ -474,7 +474,7 @@ opswitch: ODEREF, OSPTR, OITAB, OIDATA, OADDR: n.Left = walkexpr(n.Left, init) - case OEFACE, OAND, OSUB, OMUL, OADD, OOR, OXOR, OLSH, ORSH: + case OEFACE, OAND, OANDNOT, OSUB, OMUL, OADD, OOR, OXOR, OLSH, ORSH: n.Left = walkexpr(n.Left, init) n.Right = walkexpr(n.Right, init) @@ -965,14 +965,6 @@ opswitch: fn := basicnames[param] + "to" + basicnames[result] n = conv(mkcall(fn, types.Types[result], init, conv(n.Left, types.Types[param])), n.Type) - case OANDNOT: - n.Left = walkexpr(n.Left, init) - n.Op = OAND - n.SetImplicit(true) // for walkCheckPtrArithmetic - n.Right = nod(OBITNOT, n.Right, nil) - n.Right = typecheck(n.Right, ctxExpr) - n.Right = walkexpr(n.Right, init) - case ODIV, OMOD: n.Left = walkexpr(n.Left, init) n.Right = walkexpr(n.Right, init) @@ -3609,14 +3601,20 @@ func bounded(n *Node, max int64) bool { } switch n.Op { - case OAND: + case OAND, OANDNOT: v := int64(-1) - if smallintconst(n.Left) { + switch { + case smallintconst(n.Left): v = n.Left.Int64Val() - } else if smallintconst(n.Right) { + case smallintconst(n.Right): v = n.Right.Int64Val() + if n.Op == OANDNOT { + v = ^v + if !sign { + v &= 1<<uint(bits) - 1 + } + } } - if 0 <= v && v < max { return true } @@ -4045,12 +4043,8 @@ func walkCheckPtrArithmetic(n *Node, init *Nodes) *Node { case OADD: walk(n.Left) walk(n.Right) - case OSUB: + case OSUB, OANDNOT: walk(n.Left) - case OAND: - if n.Implicit() { // was OANDNOT - walk(n.Left) - } case OCONVNOP: if n.Left.Type.IsUnsafePtr() { n.Left = cheapexpr(n.Left, init) diff --git a/test/bounds.go b/test/bounds.go index 4a9c3b2d39..aa1d51b6f9 100644 --- a/test/bounds.go +++ b/test/bounds.go @@ -209,6 +209,11 @@ func main() { use(a1k[i&^0]) use(a1k[i&^-2]) // ERROR "index bounds check elided" use(a1k[i&^1]) + use(a1k[i8&^0]) + use(a1k[i8&^-128]) // ERROR "index bounds check elided" + use(a1k[ui8&^1]) // ERROR "index bounds check elided" + use(a1k[ui16&^0xf000]) + use(a1k[ui16&^0xff00]) // ERROR "index bounds check elided" // Right shift cuts the effective number of bits in the index, // but only for unsigned (signed stays negative). |