cmd/compile: tweaks to unindent some code

Prioritized the chunks of code with 8 or more levels of indentation.
Basically early breaks/returns and joining nested ifs.

Change-Id: I6817df1303226acf2eb904a29f2db720e4f7427a
Reviewed-on: https://go-review.googlesource.com/55630
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

7 files changed, 89 insertions, 92 deletions

diff --git a/src/cmd/compile/internal/gc/closure.go b/src/cmd/compile/internal/gc/closure.go
index a3a0970f71..c6e94cc4b3 100644
--- a/src/cmd/compile/internal/gc/closure.go
+++ b/src/cmd/compile/internal/gc/closure.go
@@ -463,9 +463,8 @@ func walkclosure(func_ *Node, init *Nodes) *Node {
 			Warnl(func_.Pos, "closure converted to global")
 		}
 		return func_.Func.Closure.Func.Nname
-	} else {
-		closuredebugruntimecheck(func_)
 	}
+	closuredebugruntimecheck(func_)
 
 	// Create closure in the form of a composite literal.
 	// supposing the closure captures an int i and a string s
diff --git a/src/cmd/compile/internal/gc/esc.go b/src/cmd/compile/internal/gc/esc.go
index 87a5b7f29f..afe1e5a7e5 100644
--- a/src/cmd/compile/internal/gc/esc.go
+++ b/src/cmd/compile/internal/gc/esc.go
@@ -1554,20 +1554,20 @@ func (e *EscState) esccall(call *Node, parent *Node) {
 					call.Right = arg
 				}
 				e.escassignWhyWhere(n, arg, "arg to recursive call", call) // TODO this message needs help.
-				if arg != args[0] {
-					// "..." arguments are untracked
-					for _, a := range args {
-						if Debug['m'] > 3 {
-							fmt.Printf("%v::esccall:: ... <- %S, untracked\n", linestr(lineno), a)
-						}
-						e.escassignSinkWhyWhere(arg, a, "... arg to recursive call", call)
-					}
-					// No more PPARAM processing, but keep
-					// going for PPARAMOUT.
-					args = nil
+				if arg == args[0] {
+					args = args[1:]
 					continue
 				}
-				args = args[1:]
+				// "..." arguments are untracked
+				for _, a := range args {
+					if Debug['m'] > 3 {
+						fmt.Printf("%v::esccall:: ... <- %S, untracked\n", linestr(lineno), a)
+					}
+					e.escassignSinkWhyWhere(arg, a, "... arg to recursive call", call)
+				}
+				// No more PPARAM processing, but keep
+				// going for PPARAMOUT.
+				args = nil
 
 			case PPARAMOUT:
 				cE.Retval.Append(n)
diff --git a/src/cmd/compile/internal/gc/phi.go b/src/cmd/compile/internal/gc/phi.go
index 0ce7a4b11d..b549f0ea6f 100644
--- a/src/cmd/compile/internal/gc/phi.go
+++ b/src/cmd/compile/internal/gc/phi.go
@@ -233,24 +233,25 @@ func (s *phiState) insertVarPhis(n int, var_ *Node, defs []*ssa.Block, typ *type
 					// a D-edge, or an edge whose target is in currentRoot's subtree.
 					continue
 				}
-				if !hasPhi.contains(c.ID) {
-					// Add a phi to block c for variable n.
-					hasPhi.add(c.ID)
-					v := c.NewValue0I(currentRoot.Pos, ssa.OpPhi, typ, int64(n)) // TODO: line number right?
-					// Note: we store the variable number in the phi's AuxInt field. Used temporarily by phi building.
-					s.s.addNamedValue(var_, v)
-					for i := 0; i < len(c.Preds); i++ {
-						v.AddArg(s.placeholder) // Actual args will be filled in by resolveFwdRefs.
-					}
-					if debugPhi {
-						fmt.Printf("new phi for var%d in %s: %s\n", n, c, v)
-					}
-					if !hasDef.contains(c.ID) {
-						// There's now a new definition of this variable in block c.
-						// Add it to the priority queue to explore.
-						heap.Push(priq, c)
-						hasDef.add(c.ID)
-					}
+				if hasPhi.contains(c.ID) {
+					continue
+				}
+				// Add a phi to block c for variable n.
+				hasPhi.add(c.ID)
+				v := c.NewValue0I(currentRoot.Pos, ssa.OpPhi, typ, int64(n)) // TODO: line number right?
+				// Note: we store the variable number in the phi's AuxInt field. Used temporarily by phi building.
+				s.s.addNamedValue(var_, v)
+				for i := 0; i < len(c.Preds); i++ {
+					v.AddArg(s.placeholder) // Actual args will be filled in by resolveFwdRefs.
+				}
+				if debugPhi {
+					fmt.Printf("new phi for var%d in %s: %s\n", n, c, v)
+				}
+				if !hasDef.contains(c.ID) {
+					// There's now a new definition of this variable in block c.
+					// Add it to the priority queue to explore.
+					heap.Push(priq, c)
+					hasDef.add(c.ID)
 				}
 			}
 
diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go
index a08ea0f73b..745a1efce8 100644
--- a/src/cmd/compile/internal/gc/reflect.go
+++ b/src/cmd/compile/internal/gc/reflect.go
@@ -497,14 +497,12 @@ func dgopkgpathOff(s *obj.LSym, ot int, pkg *types.Pkg) int {
 func isExportedField(ft *types.Field) (bool, *types.Pkg) {
 	if ft.Sym != nil && ft.Embedded == 0 {
 		return exportname(ft.Sym.Name), ft.Sym.Pkg
-	} else {
-		if ft.Type.Sym != nil &&
-			(ft.Type.Sym.Pkg == builtinpkg || !exportname(ft.Type.Sym.Name)) {
-			return false, ft.Type.Sym.Pkg
-		} else {
-			return true, nil
-		}
 	}
+	if ft.Type.Sym != nil &&
+		(ft.Type.Sym.Pkg == builtinpkg || !exportname(ft.Type.Sym.Name)) {
+		return false, ft.Type.Sym.Pkg
+	}
+	return true, nil
 }
 
 // dnameField dumps a reflect.name for a struct field.
diff --git a/src/cmd/compile/internal/gc/sinit.go b/src/cmd/compile/internal/gc/sinit.go
index 613cdf6e74..f38692e310 100644
--- a/src/cmd/compile/internal/gc/sinit.go
+++ b/src/cmd/compile/internal/gc/sinit.go
@@ -480,9 +480,8 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
 			n := *l
 			gdata(&n, r.Func.Closure.Func.Nname, Widthptr)
 			return true
-		} else {
-			closuredebugruntimecheck(r)
 		}
+		closuredebugruntimecheck(r)
 
 	case OCONVIFACE:
 		// This logic is mirrored in isStaticCompositeLiteral.
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 932d1f2b70..faaeed6a33 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -661,24 +661,26 @@ func (s *state) stmt(n *Node) {
 				}
 				rhs = nil
 			case OAPPEND:
-				// If we're writing the result of an append back to the same slice,
-				// handle it specially to avoid write barriers on the fast (non-growth) path.
+				// Check whether we're writing the result of an append back to the same slice.
+				// If so, we handle it specially to avoid write barriers on the fast
+				// (non-growth) path.
+				if !samesafeexpr(n.Left, rhs.List.First()) {
+					break
+				}
 				// If the slice can be SSA'd, it'll be on the stack,
 				// so there will be no write barriers,
 				// so there's no need to attempt to prevent them.
-				if samesafeexpr(n.Left, rhs.List.First()) {
-					if !s.canSSA(n.Left) {
-						if Debug_append > 0 {
-							Warnl(n.Pos, "append: len-only update")
-						}
-						s.append(rhs, true)
-						return
-					} else {
-						if Debug_append > 0 { // replicating old diagnostic message
-							Warnl(n.Pos, "append: len-only update (in local slice)")
-						}
+				if s.canSSA(n.Left) {
+					if Debug_append > 0 { // replicating old diagnostic message
+						Warnl(n.Pos, "append: len-only update (in local slice)")
 					}
+					break
+				}
+				if Debug_append > 0 {
+					Warnl(n.Pos, "append: len-only update")
 				}
+				s.append(rhs, true)
+				return
 			}
 		}
 
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index ab68c515ad..b809a8bee7 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -2636,54 +2636,52 @@ func typecheckaste(op Op, call *Node, isddd bool, tstruct *types.Type, nl Nodes,
 	n = nil
 	if nl.Len() == 1 {
 		n = nl.First()
-		if n.Type != nil {
-			if n.Type.IsFuncArgStruct() {
-				if !hasddd(tstruct) {
-					n1 := tstruct.NumFields()
-					n2 := n.Type.NumFields()
-					if n2 > n1 {
-						goto toomany
-					}
-					if n2 < n1 {
-						goto notenough
-					}
+		if n.Type != nil && n.Type.IsFuncArgStruct() {
+			if !hasddd(tstruct) {
+				n1 := tstruct.NumFields()
+				n2 := n.Type.NumFields()
+				if n2 > n1 {
+					goto toomany
 				}
+				if n2 < n1 {
+					goto notenough
+				}
+			}
 
-				lfs := tstruct.FieldSlice()
-				rfs := n.Type.FieldSlice()
-				var why string
-				for i, tl := range lfs {
-					if tl.Isddd() {
-						for _, tn := range rfs[i:] {
-							if assignop(tn.Type, tl.Type.Elem(), &why) == 0 {
-								if call != nil {
-									yyerror("cannot use %v as type %v in argument to %v%s", tn.Type, tl.Type.Elem(), call, why)
-								} else {
-									yyerror("cannot use %v as type %v in %s%s", tn.Type, tl.Type.Elem(), desc(), why)
-								}
+			lfs := tstruct.FieldSlice()
+			rfs := n.Type.FieldSlice()
+			var why string
+			for i, tl := range lfs {
+				if tl.Isddd() {
+					for _, tn := range rfs[i:] {
+						if assignop(tn.Type, tl.Type.Elem(), &why) == 0 {
+							if call != nil {
+								yyerror("cannot use %v as type %v in argument to %v%s", tn.Type, tl.Type.Elem(), call, why)
+							} else {
+								yyerror("cannot use %v as type %v in %s%s", tn.Type, tl.Type.Elem(), desc(), why)
 							}
 						}
-						goto out
 					}
+					goto out
+				}
 
-					if i >= len(rfs) {
-						goto notenough
-					}
-					tn := rfs[i]
-					if assignop(tn.Type, tl.Type, &why) == 0 {
-						if call != nil {
-							yyerror("cannot use %v as type %v in argument to %v%s", tn.Type, tl.Type, call, why)
-						} else {
-							yyerror("cannot use %v as type %v in %s%s", tn.Type, tl.Type, desc(), why)
-						}
+				if i >= len(rfs) {
+					goto notenough
+				}
+				tn := rfs[i]
+				if assignop(tn.Type, tl.Type, &why) == 0 {
+					if call != nil {
+						yyerror("cannot use %v as type %v in argument to %v%s", tn.Type, tl.Type, call, why)
+					} else {
+						yyerror("cannot use %v as type %v in %s%s", tn.Type, tl.Type, desc(), why)
 					}
 				}
+			}
 
-				if len(rfs) > len(lfs) {
-					goto toomany
-				}
-				goto out
+			if len(rfs) > len(lfs) {
+				goto toomany
 			}
+			goto out
 		}
 	}