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https://github.com/golang/go
synced 2024-11-23 02:10:03 -07:00
cmd/compile: remove typecheck.EvalConst
types2 has already done most of the constant folding parts. The only
case left is unsafe.{Alignoff,Offsetof,Sizeof} with variable size
argument, which is handled separately during typecheck.
Change-Id: I8050b7613a16b19b91751726ac07253333177f73
Reviewed-on: https://go-review.googlesource.com/c/go/+/469595
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
Cuong Manh Le
Gopher Robot
parent
13f0b8f421
commit
25bc96dbd2
@ -11,7 +11,6 @@ import (
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"internal/types/errors"
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"math"
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"math/big"
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"strings"
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"unicode"
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"cmd/compile/internal/base"
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@ -349,178 +348,6 @@ var tokenForOp = [...]token.Token{
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ir.ORSH: token.SHR,
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}
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// EvalConst returns a constant-evaluated expression equivalent to n.
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// If n is not a constant, EvalConst returns n.
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// Otherwise, EvalConst returns a new OLITERAL with the same value as n,
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// and with .Orig pointing back to n.
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func EvalConst(n ir.Node) ir.Node {
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// Pick off just the opcodes that can be constant evaluated.
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switch n.Op() {
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case ir.OPLUS, ir.ONEG, ir.OBITNOT, ir.ONOT:
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n := n.(*ir.UnaryExpr)
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nl := n.X
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if nl.Op() == ir.OLITERAL {
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var prec uint
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if n.Type().IsUnsigned() {
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prec = uint(n.Type().Size() * 8)
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}
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return OrigConst(n, constant.UnaryOp(tokenForOp[n.Op()], nl.Val(), prec))
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}
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case ir.OADD, ir.OSUB, ir.OMUL, ir.ODIV, ir.OMOD, ir.OOR, ir.OXOR, ir.OAND, ir.OANDNOT:
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n := n.(*ir.BinaryExpr)
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nl, nr := n.X, n.Y
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if nl.Op() == ir.OLITERAL && nr.Op() == ir.OLITERAL {
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rval := nr.Val()
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// check for divisor underflow in complex division (see issue 20227)
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if n.Op() == ir.ODIV && n.Type().IsComplex() && constant.Sign(square(constant.Real(rval))) == 0 && constant.Sign(square(constant.Imag(rval))) == 0 {
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base.Errorf("complex division by zero")
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n.SetType(nil)
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return n
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}
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if (n.Op() == ir.ODIV || n.Op() == ir.OMOD) && constant.Sign(rval) == 0 {
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base.Errorf("division by zero")
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n.SetType(nil)
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return n
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}
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tok := tokenForOp[n.Op()]
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if n.Op() == ir.ODIV && n.Type().IsInteger() {
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tok = token.QUO_ASSIGN // integer division
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}
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return OrigConst(n, constant.BinaryOp(nl.Val(), tok, rval))
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}
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case ir.OOROR, ir.OANDAND:
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n := n.(*ir.LogicalExpr)
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nl, nr := n.X, n.Y
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if nl.Op() == ir.OLITERAL && nr.Op() == ir.OLITERAL {
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return OrigConst(n, constant.BinaryOp(nl.Val(), tokenForOp[n.Op()], nr.Val()))
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}
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case ir.OEQ, ir.ONE, ir.OLT, ir.OLE, ir.OGT, ir.OGE:
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n := n.(*ir.BinaryExpr)
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nl, nr := n.X, n.Y
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if nl.Op() == ir.OLITERAL && nr.Op() == ir.OLITERAL {
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return OrigBool(n, constant.Compare(nl.Val(), tokenForOp[n.Op()], nr.Val()))
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}
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case ir.OLSH, ir.ORSH:
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n := n.(*ir.BinaryExpr)
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nl, nr := n.X, n.Y
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if nl.Op() == ir.OLITERAL && nr.Op() == ir.OLITERAL {
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// shiftBound from go/types; "so we can express smallestFloat64" (see issue #44057)
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const shiftBound = 1023 - 1 + 52
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s, ok := constant.Uint64Val(nr.Val())
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if !ok || s > shiftBound {
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base.Errorf("invalid shift count %v", nr)
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n.SetType(nil)
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break
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}
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return OrigConst(n, constant.Shift(toint(nl.Val()), tokenForOp[n.Op()], uint(s)))
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}
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case ir.OCONV, ir.ORUNESTR:
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n := n.(*ir.ConvExpr)
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nl := n.X
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if ir.OKForConst[n.Type().Kind()] && nl.Op() == ir.OLITERAL {
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return OrigConst(n, convertVal(nl.Val(), n.Type(), true))
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}
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case ir.OCONVNOP:
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n := n.(*ir.ConvExpr)
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nl := n.X
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if ir.OKForConst[n.Type().Kind()] && nl.Op() == ir.OLITERAL {
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// set so n.Orig gets OCONV instead of OCONVNOP
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n.SetOp(ir.OCONV)
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return OrigConst(n, nl.Val())
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}
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case ir.OADDSTR:
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// Merge adjacent constants in the argument list.
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n := n.(*ir.AddStringExpr)
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s := n.List
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need := 0
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for i := 0; i < len(s); i++ {
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if i == 0 || !ir.IsConst(s[i-1], constant.String) || !ir.IsConst(s[i], constant.String) {
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// Can't merge s[i] into s[i-1]; need a slot in the list.
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need++
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}
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}
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if need == len(s) {
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return n
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}
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if need == 1 {
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var strs []string
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for _, c := range s {
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strs = append(strs, ir.StringVal(c))
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}
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return OrigConst(n, constant.MakeString(strings.Join(strs, "")))
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}
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newList := make([]ir.Node, 0, need)
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for i := 0; i < len(s); i++ {
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if ir.IsConst(s[i], constant.String) && i+1 < len(s) && ir.IsConst(s[i+1], constant.String) {
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// merge from i up to but not including i2
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var strs []string
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i2 := i
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for i2 < len(s) && ir.IsConst(s[i2], constant.String) {
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strs = append(strs, ir.StringVal(s[i2]))
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i2++
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}
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nl := ir.Copy(n).(*ir.AddStringExpr)
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nl.List = s[i:i2]
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newList = append(newList, OrigConst(nl, constant.MakeString(strings.Join(strs, ""))))
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i = i2 - 1
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} else {
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newList = append(newList, s[i])
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}
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}
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nn := ir.Copy(n).(*ir.AddStringExpr)
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nn.List = newList
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return nn
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case ir.OCAP, ir.OLEN:
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n := n.(*ir.UnaryExpr)
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nl := n.X
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switch nl.Type().Kind() {
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case types.TSTRING:
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if ir.IsConst(nl, constant.String) {
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return OrigInt(n, int64(len(ir.StringVal(nl))))
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}
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case types.TARRAY:
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if !anyCallOrChan(nl) {
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return OrigInt(n, nl.Type().NumElem())
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}
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}
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case ir.OREAL:
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n := n.(*ir.UnaryExpr)
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nl := n.X
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if nl.Op() == ir.OLITERAL {
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return OrigConst(n, constant.Real(nl.Val()))
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}
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case ir.OIMAG:
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n := n.(*ir.UnaryExpr)
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nl := n.X
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if nl.Op() == ir.OLITERAL {
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return OrigConst(n, constant.Imag(nl.Val()))
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}
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case ir.OCOMPLEX:
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n := n.(*ir.BinaryExpr)
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nl, nr := n.X, n.Y
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if nl.Op() == ir.OLITERAL && nr.Op() == ir.OLITERAL {
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return OrigConst(n, makeComplex(nl.Val(), nr.Val()))
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}
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}
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return n
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}
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func makeFloat64(f float64) constant.Value {
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if math.IsInf(f, 0) {
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base.Fatalf("infinity is not a valid constant")
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@ -532,10 +359,6 @@ func makeComplex(real, imag constant.Value) constant.Value {
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return constant.BinaryOp(constant.ToFloat(real), token.ADD, constant.MakeImag(constant.ToFloat(imag)))
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}
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func square(x constant.Value) constant.Value {
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return constant.BinaryOp(x, token.MUL, x)
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}
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// For matching historical "constant OP overflow" error messages.
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// TODO(mdempsky): Replace with error messages like go/types uses.
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var overflowNames = [...]string{
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@ -733,13 +556,6 @@ func callOrChan(n ir.Node) bool {
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return false
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}
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// anyCallOrChan reports whether n contains any calls or channel operations.
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func anyCallOrChan(n ir.Node) bool {
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return ir.Any(n, func(n ir.Node) bool {
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return callOrChan(n)
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})
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}
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// evalunsafe evaluates a package unsafe operation and returns the result.
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func evalunsafe(n ir.Node) int64 {
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switch n.Op() {
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@ -355,10 +355,6 @@ func typecheck(n ir.Node, top int) (res ir.Node) {
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types.CheckSize(t)
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}
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}
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if t != nil {
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n = EvalConst(n)
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t = n.Type()
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}
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// TODO(rsc): Lots of the complexity here is because typecheck can
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// see OTYPE, ONAME, and OLITERAL nodes multiple times.
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@ -516,9 +512,6 @@ func typecheck1(n ir.Node, top int) ir.Node {
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if t != nil {
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n.X, n.Y = l, r
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n.SetType(types.UntypedBool)
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if con := EvalConst(n); con.Op() == ir.OLITERAL {
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return con
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}
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n.X, n.Y = defaultlit2(l, r, true)
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}
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return n
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