cmd/compile: remove redundant function idom

Change-Id: Ib14b5421bb5e407bbd4d3cbfc68c92d3dd257cb1
Reviewed-on: https://go-review.googlesource.com/30732
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/ssa/func.go

@@ -451,23 +451,20 @@ func (f *Func) postorder() []*Block {
 	return f.cachedPostorder
 }
 
-// idom returns a map from block ID to the immediate dominator of that block.
+// Idom returns a map from block ID to the immediate dominator of that block.
 // f.Entry.ID maps to nil. Unreachable blocks map to nil as well.
-func (f *Func) idom() []*Block {
+func (f *Func) Idom() []*Block {
 	if f.cachedIdom == nil {
 		f.cachedIdom = dominators(f)
 	}
 	return f.cachedIdom
 }
-func (f *Func) Idom() []*Block {
-	return f.idom()
-}
 
 // sdom returns a sparse tree representing the dominator relationships
 // among the blocks of f.
 func (f *Func) sdom() SparseTree {
 	if f.cachedSdom == nil {
-		f.cachedSdom = newSparseTree(f, f.idom())
+		f.cachedSdom = newSparseTree(f, f.Idom())
 	}
 	return f.cachedSdom
 }

src/cmd/compile/internal/ssa/lca.go

@@ -30,7 +30,7 @@ type lcaRangeBlock struct {
 }
 
 func makeLCArange(f *Func) *lcaRange {
-	dom := f.idom()
+	dom := f.Idom()
 
 	// Build tree
 	blocks := make([]lcaRangeBlock, f.NumBlocks())

src/cmd/compile/internal/ssa/prove.go

@@ -463,7 +463,7 @@ func prove(f *Func) {
 	})
 
 	ft := newFactsTable()
-	idom := f.idom()
+	idom := f.Idom()
 	sdom := f.sdom()
 
 	// DFS on the dominator tree.

src/cmd/compile/internal/ssa/sparsetreemap.go

@@ -57,7 +57,7 @@ type SparseTreeHelper struct {
 // NewSparseTreeHelper returns a SparseTreeHelper for use
 // in the gc package, for example in phi-function placement.
 func NewSparseTreeHelper(f *Func) *SparseTreeHelper {
-	dom := f.idom()
+	dom := f.Idom()
 	ponums := make([]int32, f.NumBlocks())
 	po := postorderWithNumbering(f, ponums)
 	return makeSparseTreeHelper(newSparseTree(f, dom), dom, po, ponums)

src/cmd/compile/internal/ssa/tighten.go

@@ -56,7 +56,7 @@ func tighten(f *Func) {
 
 	// Grab loop information.
 	// We use this to make sure we don't tighten a value into a (deeper) loop.
-	idom := f.idom()
+	idom := f.Idom()
 	loops := f.loopnest()
 	loops.calculateDepths()