1 files changed, 0 insertions, 187 deletions
diff --git a/vendor/golang.org/x/tools/go/ssa/blockopt.go b/vendor/golang.org/x/tools/go/ssa/blockopt.go
deleted file mode 100644
index e79260a..0000000
--- a/vendor/golang.org/x/tools/go/ssa/blockopt.go
+++ /dev/null
@@ -1,187 +0,0 @@
-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package ssa
-
-// Simple block optimizations to simplify the control flow graph.
-
-// TODO(adonovan): opt: instead of creating several "unreachable" blocks
-// per function in the Builder, reuse a single one (e.g. at Blocks[1])
-// to reduce garbage.
-
-import (
-	"fmt"
-	"os"
-)
-
-// If true, perform sanity checking and show progress at each
-// successive iteration of optimizeBlocks.  Very verbose.
-const debugBlockOpt = false
-
-// markReachable sets Index=-1 for all blocks reachable from b.
-func markReachable(b *BasicBlock) {
-	b.Index = -1
-	for _, succ := range b.Succs {
-		if succ.Index == 0 {
-			markReachable(succ)
-		}
-	}
-}
-
-// deleteUnreachableBlocks marks all reachable blocks of f and
-// eliminates (nils) all others, including possibly cyclic subgraphs.
-//
-func deleteUnreachableBlocks(f *Function) {
-	const white, black = 0, -1
-	// We borrow b.Index temporarily as the mark bit.
-	for _, b := range f.Blocks {
-		b.Index = white
-	}
-	markReachable(f.Blocks[0])
-	if f.Recover != nil {
-		markReachable(f.Recover)
-	}
-	for i, b := range f.Blocks {
-		if b.Index == white {
-			for _, c := range b.Succs {
-				if c.Index == black {
-					c.removePred(b) // delete white->black edge
-				}
-			}
-			if debugBlockOpt {
-				fmt.Fprintln(os.Stderr, "unreachable", b)
-			}
-			f.Blocks[i] = nil // delete b
-		}
-	}
-	f.removeNilBlocks()
-}
-
-// jumpThreading attempts to apply simple jump-threading to block b,
-// in which a->b->c become a->c if b is just a Jump.
-// The result is true if the optimization was applied.
-//
-func jumpThreading(f *Function, b *BasicBlock) bool {
-	if b.Index == 0 {
-		return false // don't apply to entry block
-	}
-	if b.Instrs == nil {
-		return false
-	}
-	if _, ok := b.Instrs[0].(*Jump); !ok {
-		return false // not just a jump
-	}
-	c := b.Succs[0]
-	if c == b {
-		return false // don't apply to degenerate jump-to-self.
-	}
-	if c.hasPhi() {
-		return false // not sound without more effort
-	}
-	for j, a := range b.Preds {
-		a.replaceSucc(b, c)
-
-		// If a now has two edges to c, replace its degenerate If by Jump.
-		if len(a.Succs) == 2 && a.Succs[0] == c && a.Succs[1] == c {
-			jump := new(Jump)
-			jump.setBlock(a)
-			a.Instrs[len(a.Instrs)-1] = jump
-			a.Succs = a.Succs[:1]
-			c.removePred(b)
-		} else {
-			if j == 0 {
-				c.replacePred(b, a)
-			} else {
-				c.Preds = append(c.Preds, a)
-			}
-		}
-
-		if debugBlockOpt {
-			fmt.Fprintln(os.Stderr, "jumpThreading", a, b, c)
-		}
-	}
-	f.Blocks[b.Index] = nil // delete b
-	return true
-}
-
-// fuseBlocks attempts to apply the block fusion optimization to block
-// a, in which a->b becomes ab if len(a.Succs)==len(b.Preds)==1.
-// The result is true if the optimization was applied.
-//
-func fuseBlocks(f *Function, a *BasicBlock) bool {
-	if len(a.Succs) != 1 {
-		return false
-	}
-	b := a.Succs[0]
-	if len(b.Preds) != 1 {
-		return false
-	}
-
-	// Degenerate &&/|| ops may result in a straight-line CFG
-	// containing φ-nodes. (Ideally we'd replace such them with
-	// their sole operand but that requires Referrers, built later.)
-	if b.hasPhi() {
-		return false // not sound without further effort
-	}
-
-	// Eliminate jump at end of A, then copy all of B across.
-	a.Instrs = append(a.Instrs[:len(a.Instrs)-1], b.Instrs...)
-	for _, instr := range b.Instrs {
-		instr.setBlock(a)
-	}
-
-	// A inherits B's successors
-	a.Succs = append(a.succs2[:0], b.Succs...)
-
-	// Fix up Preds links of all successors of B.
-	for _, c := range b.Succs {
-		c.replacePred(b, a)
-	}
-
-	if debugBlockOpt {
-		fmt.Fprintln(os.Stderr, "fuseBlocks", a, b)
-	}
-
-	f.Blocks[b.Index] = nil // delete b
-	return true
-}
-
-// optimizeBlocks() performs some simple block optimizations on a
-// completed function: dead block elimination, block fusion, jump
-// threading.
-//
-func optimizeBlocks(f *Function) {
-	deleteUnreachableBlocks(f)
-
-	// Loop until no further progress.
-	changed := true
-	for changed {
-		changed = false
-
-		if debugBlockOpt {
-			f.WriteTo(os.Stderr)
-			mustSanityCheck(f, nil)
-		}
-
-		for _, b := range f.Blocks {
-			// f.Blocks will temporarily contain nils to indicate
-			// deleted blocks; we remove them at the end.
-			if b == nil {
-				continue
-			}
-
-			// Fuse blocks.  b->c becomes bc.
-			if fuseBlocks(f, b) {
-				changed = true
-			}
-
-			// a->b->c becomes a->c if b contains only a Jump.
-			if jumpThreading(f, b) {
-				changed = true
-				continue // (b was disconnected)
-			}
-		}
-	}
-	f.removeNilBlocks()
-}