[dev.ssa] cmd/compile: add constBool helpers

Change-Id: I1f93ea65bbdc895cd4eff7545e1688a64d85aae5
Reviewed-on: https://go-review.googlesource.com/14520
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

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

@@ -371,7 +371,10 @@ func (s *state) entryNewValue2(op ssa.Op, t ssa.Type, arg0, arg1 *ssa.Value) *ss
 	return s.f.Entry.NewValue2(s.peekLine(), op, t, arg0, arg1)
 }
 
-// constInt* routines add a new const int value to the entry block.
+// const* routines add a new const value to the entry block.
+func (s *state) constBool(c bool) *ssa.Value {
+	return s.f.ConstBool(s.peekLine(), Types[TBOOL], c)
+}
 func (s *state) constInt8(t ssa.Type, c int8) *ssa.Value {
 	return s.f.ConstInt8(s.peekLine(), t, c)
 }
@@ -647,7 +650,7 @@ func (s *state) stmt(n *Node) {
 		if n.Left != nil {
 			cond = s.expr(n.Left)
 		} else {
-			cond = s.entryNewValue0I(ssa.OpConstBool, Types[TBOOL], 1) // 1 = true
+			cond = s.constBool(true)
 		}
 		b = s.endBlock()
 		b.Kind = ssa.BlockIf
@@ -1223,11 +1226,7 @@ func (s *state) expr(n *Node) *ssa.Value {
 		case CTSTR:
 			return s.entryNewValue0A(ssa.OpConstString, n.Type, n.Val().U)
 		case CTBOOL:
-			if n.Val().U.(bool) {
-				return s.entryNewValue0I(ssa.OpConstBool, Types[TBOOL], 1) // 1 = true
-			} else {
-				return s.entryNewValue0I(ssa.OpConstBool, Types[TBOOL], 0) // 0 = false
-			}
+			return s.constBool(n.Val().U.(bool))
 		case CTNIL:
 			t := n.Type
 			switch {
@@ -1947,7 +1946,7 @@ func (s *state) zeroVal(t *Type) *ssa.Value {
 	case t.IsPtr():
 		return s.entryNewValue0(ssa.OpConstNil, t)
 	case t.IsBoolean():
-		return s.entryNewValue0I(ssa.OpConstBool, Types[TBOOL], 0) // 0 = false
+		return s.constBool(false)
 	case t.IsInterface():
 		return s.entryNewValue0(ssa.OpConstInterface, t)
 	case t.IsSlice():

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

@@ -266,6 +266,14 @@ func (b *Block) NewValue3I(line int32, op Op, t Type, aux int64, arg0, arg1, arg
 }
 
 // ConstInt returns an int constant representing its argument.
+func (f *Func) ConstBool(line int32, t Type, c bool) *Value {
+	// TODO: cache?
+	i := int64(0)
+	if c {
+		i = 1
+	}
+	return f.Entry.NewValue0I(line, OpConstBool, t, i)
+}
 func (f *Func) ConstInt8(line int32, t Type, c int8) *Value {
 	// TODO: cache?
 	return f.Entry.NewValue0I(line, OpConst8, t, int64(c))