package ssa

import "cmd/compile/internal/base"

// tighten moves Values closer to the Blocks in which they are used.
// This can reduce the amount of register spilling required,
// if it doesn't also create more live values.
// A Value can be moved to any block that
// dominates all blocks in which it is used.
func tighten(f *Func) {
	if base.Flag.N != 0 && len(f.Blocks) < 10000 {
		// Skip the optimization in -N mode, except for huge functions.

	nv := sort.Search(len(c.values), func(i int) bool { return c.values[i].ID == 0 })
	xv := c.values[:nv]
	for i := range xv {
		xv[i] = Value{}
	}
	nb := sort.Search(len(c.blocks), func(i int) bool { return c.blocks[i].ID == 0 })
	xb := c.blocks[:nb]
	for i := range xb {
		xb[i] = Block{}
	}
	nl := sort.Search(len(c.locs), func(i int) bool { return c.locs[i] == nil })
	xl := c.locs[:nl]
	for i := range xl {
		xl[i] = nil

// parseSupplementalGroupAnnotation parses the group annotation into blocks.
func parseSupplementalGroupAnnotation(groups string) ([]Block, error) {
	blocks := []Block{}
	segments := strings.Split(groups, ",")
	for _, segment := range segments {
		block, err := ParseBlock(segment)
		if err != nil {
			return nil, err
		}
		blocks = append(blocks, block)
	}
	if len(blocks) == 0 {

				}
				if fun.blocks["entry"].Kind != BlockExit {
					t.Errorf("expected entry to be BlockExit; found kind %s", fun.blocks["entry"].Kind.String())
				}
			} else {
				if len(fun.f.Blocks) != 3 {
					t.Fatalf("expected 3 block after branchelim and deadcode; found %d", len(fun.f.Blocks))
				}
			}
		})
	}
}

// Test that a trivial if/else is eliminated

	EvGoBlock           = 20 // goroutine blocks [timestamp, stack]
	EvGoUnblock         = 21 // goroutine is unblocked [timestamp, goroutine id, seq, stack]
	EvGoBlockSend       = 22 // goroutine blocks on chan send [timestamp, stack]
	EvGoBlockRecv       = 23 // goroutine blocks on chan recv [timestamp, stack]
	EvGoBlockSelect     = 24 // goroutine blocks on select [timestamp, stack]

	for name, counts := range cover.Counters {
		blocks := cover.Blocks[name]
		for i := range counts {
			stmts := int64(blocks[i].Stmts)
			total += stmts
			count = atomic.LoadUint32(&counts[i]) // For -mode=atomic.
			if count > 0 {
				active += stmts
			}
			if f != nil {
				_, err := fmt.Fprintf(f, "%s:%d.%d,%d.%d %d %d\n", name,
					blocks[i].Line0, blocks[i].Col0,
					blocks[i].Line1, blocks[i].Col1,
					stmts,

// license that can be found in the LICENSE file.

package ssa

import "cmd/internal/src"

// trim removes blocks with no code in them.
// These blocks were inserted to remove critical edges.
func trim(f *Func) {
	n := 0
	for _, b := range f.Blocks {
		if !trimmableBlock(b) {
			f.Blocks[n] = b
			n++
			continue
		}

		bPos := b.Pos
		bIsStmt := bPos.IsStmt() == src.PosIsStmt

	regalloc(f.f)
	checkFunc(f.f)
	// Spill should be moved to exit2.
	if numSpills(f.blocks["loop1"]) != 0 {
		t.Errorf("spill present from loop1")
	}
	if numSpills(f.blocks["loop2"]) != 0 {
		t.Errorf("spill present in loop2")
	}
	if numSpills(f.blocks["exit1"]) != 0 {
		t.Errorf("spill present in exit1")
	}
	if numSpills(f.blocks["exit2"]) != 1 {
		t.Errorf("spill missing in exit2")
	}

}

     start
      a
       block.
More text.

      Blocks
    can

  have
    blank
      lines.
-- gofmt --
Text.

	A tab-indented
	(no, not eight-space indented)
	code block and haiku.

More text.

	One space
	 is
	  enough
	   to
	    start
	     a
	      block.

More text.

	    Blocks
	  can

	have
	  blank
	    lines.
-- markdown --

	fuse(fun.f, fuseTypePlain)
	deadcode(fun.f)

	CheckFunc(fun.f)
	foundDifferentCheck := false
	for _, b := range fun.f.Blocks {
		if b == fun.blocks["secondCheck"] && isNilCheck(b) {
			t.Errorf("secondCheck was not eliminated")
		}
		if b == fun.blocks["differentCheck"] && isNilCheck(b) {
			foundDifferentCheck = true
		}
	}
	if !foundDifferentCheck {