mirror of https://github.com/golang/go.git
go/ssa: Move BasicBlock operations into block.go
Move the BasicBlock related functions and methods into their own file. Miscellaneous cleanup. Updates golang/go#48525 Change-Id: If1c89cf53a4dba25d0c8b703e53c79eb27957f9c Reviewed-on: https://go-review.googlesource.com/c/tools/+/386316 Reviewed-by: Zvonimir Pavlinovic <zpavlinovic@google.com> Reviewed-by: Robert Findley <rfindley@google.com> Trust: Tim King <taking@google.com> Run-TryBot: Tim King <taking@google.com> gopls-CI: kokoro <noreply+kokoro@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
This commit is contained in:
Tim King
parent
7103138b8b
commit
fc479468e8
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@ -0,0 +1,118 @@
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ssa
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import "fmt"
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// This file implements the BasicBlock type.
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// addEdge adds a control-flow graph edge from from to to.
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func addEdge(from, to *BasicBlock) {
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from.Succs = append(from.Succs, to)
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to.Preds = append(to.Preds, from)
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}
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// Parent returns the function that contains block b.
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func (b *BasicBlock) Parent() *Function { return b.parent }
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// String returns a human-readable label of this block.
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// It is not guaranteed unique within the function.
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//
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func (b *BasicBlock) String() string {
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return fmt.Sprintf("%d", b.Index)
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}
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// emit appends an instruction to the current basic block.
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// If the instruction defines a Value, it is returned.
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//
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func (b *BasicBlock) emit(i Instruction) Value {
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i.setBlock(b)
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b.Instrs = append(b.Instrs, i)
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v, _ := i.(Value)
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return v
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}
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// predIndex returns the i such that b.Preds[i] == c or panics if
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// there is none.
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func (b *BasicBlock) predIndex(c *BasicBlock) int {
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for i, pred := range b.Preds {
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if pred == c {
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return i
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}
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}
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panic(fmt.Sprintf("no edge %s -> %s", c, b))
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}
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// hasPhi returns true if b.Instrs contains φ-nodes.
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func (b *BasicBlock) hasPhi() bool {
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_, ok := b.Instrs[0].(*Phi)
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return ok
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}
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// phis returns the prefix of b.Instrs containing all the block's φ-nodes.
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func (b *BasicBlock) phis() []Instruction {
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for i, instr := range b.Instrs {
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if _, ok := instr.(*Phi); !ok {
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return b.Instrs[:i]
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}
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}
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return nil // unreachable in well-formed blocks
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}
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// replacePred replaces all occurrences of p in b's predecessor list with q.
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// Ordinarily there should be at most one.
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//
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func (b *BasicBlock) replacePred(p, q *BasicBlock) {
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for i, pred := range b.Preds {
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if pred == p {
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b.Preds[i] = q
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}
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}
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}
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// replaceSucc replaces all occurrences of p in b's successor list with q.
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// Ordinarily there should be at most one.
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//
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func (b *BasicBlock) replaceSucc(p, q *BasicBlock) {
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for i, succ := range b.Succs {
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if succ == p {
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b.Succs[i] = q
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}
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}
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}
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// removePred removes all occurrences of p in b's
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// predecessor list and φ-nodes.
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// Ordinarily there should be at most one.
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//
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func (b *BasicBlock) removePred(p *BasicBlock) {
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phis := b.phis()
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// We must preserve edge order for φ-nodes.
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j := 0
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for i, pred := range b.Preds {
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if pred != p {
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b.Preds[j] = b.Preds[i]
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// Strike out φ-edge too.
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for _, instr := range phis {
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phi := instr.(*Phi)
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phi.Edges[j] = phi.Edges[i]
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}
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j++
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}
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}
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// Nil out b.Preds[j:] and φ-edges[j:] to aid GC.
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for i := j; i < len(b.Preds); i++ {
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b.Preds[i] = nil
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for _, instr := range phis {
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instr.(*Phi).Edges[i] = nil
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}
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}
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b.Preds = b.Preds[:j]
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for _, instr := range phis {
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phi := instr.(*Phi)
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phi.Edges = phi.Edges[:j]
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}
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}
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111
go/ssa/func.go
111
go/ssa/func.go
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@ -4,7 +4,7 @@
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package ssa
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// This file implements the Function and BasicBlock types.
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// This file implements the Function type.
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import (
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"bytes"
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@ -17,115 +17,6 @@ import (
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"strings"
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)
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// addEdge adds a control-flow graph edge from from to to.
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func addEdge(from, to *BasicBlock) {
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from.Succs = append(from.Succs, to)
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to.Preds = append(to.Preds, from)
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}
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// Parent returns the function that contains block b.
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func (b *BasicBlock) Parent() *Function { return b.parent }
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// String returns a human-readable label of this block.
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// It is not guaranteed unique within the function.
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//
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func (b *BasicBlock) String() string {
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return fmt.Sprintf("%d", b.Index)
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}
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// emit appends an instruction to the current basic block.
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// If the instruction defines a Value, it is returned.
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//
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func (b *BasicBlock) emit(i Instruction) Value {
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i.setBlock(b)
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b.Instrs = append(b.Instrs, i)
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v, _ := i.(Value)
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return v
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}
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// predIndex returns the i such that b.Preds[i] == c or panics if
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// there is none.
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func (b *BasicBlock) predIndex(c *BasicBlock) int {
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for i, pred := range b.Preds {
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if pred == c {
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return i
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}
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}
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panic(fmt.Sprintf("no edge %s -> %s", c, b))
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}
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// hasPhi returns true if b.Instrs contains φ-nodes.
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func (b *BasicBlock) hasPhi() bool {
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_, ok := b.Instrs[0].(*Phi)
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return ok
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}
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// phis returns the prefix of b.Instrs containing all the block's φ-nodes.
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func (b *BasicBlock) phis() []Instruction {
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for i, instr := range b.Instrs {
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if _, ok := instr.(*Phi); !ok {
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return b.Instrs[:i]
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}
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}
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return nil // unreachable in well-formed blocks
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}
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// replacePred replaces all occurrences of p in b's predecessor list with q.
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// Ordinarily there should be at most one.
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//
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func (b *BasicBlock) replacePred(p, q *BasicBlock) {
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for i, pred := range b.Preds {
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if pred == p {
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b.Preds[i] = q
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}
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}
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}
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// replaceSucc replaces all occurrences of p in b's successor list with q.
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// Ordinarily there should be at most one.
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//
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func (b *BasicBlock) replaceSucc(p, q *BasicBlock) {
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for i, succ := range b.Succs {
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if succ == p {
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b.Succs[i] = q
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}
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}
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}
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// removePred removes all occurrences of p in b's
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// predecessor list and φ-nodes.
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// Ordinarily there should be at most one.
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//
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func (b *BasicBlock) removePred(p *BasicBlock) {
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phis := b.phis()
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// We must preserve edge order for φ-nodes.
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j := 0
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for i, pred := range b.Preds {
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if pred != p {
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b.Preds[j] = b.Preds[i]
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// Strike out φ-edge too.
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for _, instr := range phis {
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phi := instr.(*Phi)
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phi.Edges[j] = phi.Edges[i]
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}
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j++
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}
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}
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// Nil out b.Preds[j:] and φ-edges[j:] to aid GC.
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for i := j; i < len(b.Preds); i++ {
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b.Preds[i] = nil
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for _, instr := range phis {
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instr.(*Phi).Edges[i] = nil
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}
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}
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b.Preds = b.Preds[:j]
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for _, instr := range phis {
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phi := instr.(*Phi)
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phi.Edges = phi.Edges[:j]
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}
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}
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// Destinations associated with unlabelled for/switch/select stmts.
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// We push/pop one of these as we enter/leave each construct and for
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// each BranchStmt we scan for the innermost target of the right type.
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