cmd/compile/internal/ssa: remove linkedBlocks and its uses

The use of predFn/succFn is not needed since CL 22401.

Change-Id: Icc39190bb7b0e85541c75da2d564093d551751d3
Reviewed-on: https://go-review.googlesource.com/c/go/+/659555
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>

diff --git a/src/cmd/compile/internal/ssa/dom.go b/src/cmd/compile/internal/ssa/dom.go
index 39ba4d1647b222534cfc6266cb1ebced62066b10..1aa0c2db564b8e7cdd22c633f41134596efcacfb 100644 (file)
--- a/src/cmd/compile/internal/ssa/dom.go
+++ b/src/cmd/compile/internal/ssa/dom.go
@@ -55,21 +55,14 @@ func postorderWithNumbering(f *Func, ponums []int32) []*Block {
        return order
 }
 
-type linkedBlocks func(*Block) []Edge
-
 func dominators(f *Func) []*Block {
-       preds := func(b *Block) []Edge { return b.Preds }
-       succs := func(b *Block) []Edge { return b.Succs }
-
-       //TODO: benchmark and try to find criteria for swapping between
+       // TODO: benchmark and try to find criteria for swapping between
        // dominatorsSimple and dominatorsLT
-       return f.dominatorsLTOrig(f.Entry, preds, succs)
+       return f.dominatorsLTOrig(f.Entry)
 }
 
-// dominatorsLTOrig runs Lengauer-Tarjan to compute a dominator tree starting at
-// entry and using predFn/succFn to find predecessors/successors to allow
-// computing both dominator and post-dominator trees.
-func (f *Func) dominatorsLTOrig(entry *Block, predFn linkedBlocks, succFn linkedBlocks) []*Block {
+// dominatorsLTOrig runs Lengauer-Tarjan to compute a dominator tree starting at entry.
+func (f *Func) dominatorsLTOrig(entry *Block) []*Block {
        // Adapted directly from the original TOPLAS article's "simple" algorithm
 
        maxBlockID := entry.Func.NumBlocks()
@@ -95,13 +88,13 @@ func (f *Func) dominatorsLTOrig(entry *Block, predFn linkedBlocks, succFn linked
 
        // Step 1. Carry out a depth first search of the problem graph. Number
        // the vertices from 1 to n as they are reached during the search.
-       n := f.dfsOrig(entry, succFn, semi, vertex, label, parent)
+       n := f.dfsOrig(entry, semi, vertex, label, parent)
 
        for i := n; i >= 2; i-- {
                w := vertex[i]
 
                // step2 in TOPLAS paper
-               for _, e := range predFn(fromID[w]) {
+               for _, e := range fromID[w].Preds {
                        v := e.b
                        if semi[v.ID] == 0 {
                                // skip unreachable predecessor
@@ -148,7 +141,7 @@ func (f *Func) dominatorsLTOrig(entry *Block, predFn linkedBlocks, succFn linked
 // (in arbitrary order).  This is a de-recursed version of dfs from the
 // original Tarjan-Lengauer TOPLAS article.  It's important to return the
 // same values for parent as the original algorithm.
-func (f *Func) dfsOrig(entry *Block, succFn linkedBlocks, semi, vertex, label, parent []ID) ID {
+func (f *Func) dfsOrig(entry *Block, semi, vertex, label, parent []ID) ID {
        n := ID(0)
        s := make([]*Block, 0, 256)
        s = append(s, entry)
@@ -166,7 +159,7 @@ func (f *Func) dfsOrig(entry *Block, succFn linkedBlocks, semi, vertex, label, p
                vertex[n] = v.ID
                label[v.ID] = v.ID
                // ancestor[v] already zero
-               for _, e := range succFn(v) {
+               for _, e := range v.Succs {
                        w := e.b
                        // if it has a dfnum, we've already visited it
                        if semi[w.ID] == 0 {