diff --git a/src/cmd/internal/gc/bits.go b/src/cmd/internal/gc/bits.go
index 95421e5..6e6ffe9 100644
--- a/src/cmd/internal/gc/bits.go
+++ b/src/cmd/internal/gc/bits.go
@@ -141,7 +141,7 @@
 		if first != 0 {
 			first = 0
 		} else {
-			fp += fmt.Sprintf(" ")
+			fp += " "
 		}
 		if var_[i].node == nil || var_[i].node.Sym == nil {
 			fp += fmt.Sprintf("$%d", i)
diff --git a/src/cmd/internal/gc/fmt.go b/src/cmd/internal/gc/fmt.go
index 084cf8a..869aaa0 100644
--- a/src/cmd/internal/gc/fmt.go
+++ b/src/cmd/internal/gc/fmt.go
@@ -242,17 +242,17 @@
 		break
 
 	case EscHeap:
-		fp += fmt.Sprintf(" esc(h)")
+		fp += " esc(h)"
 
 	case EscScope:
-		fp += fmt.Sprintf(" esc(s)")
+		fp += " esc(s)"
 
 	case EscNone:
-		fp += fmt.Sprintf(" esc(no)")
+		fp += " esc(no)"
 
 	case EscNever:
 		if c == 0 {
-			fp += fmt.Sprintf(" esc(N)")
+			fp += " esc(N)"
 		}
 
 	default:
@@ -284,11 +284,11 @@
 	}
 
 	if n.Addrtaken != 0 {
-		fp += fmt.Sprintf(" addrtaken")
+		fp += " addrtaken"
 	}
 
 	if n.Assigned != 0 {
-		fp += fmt.Sprintf(" assigned")
+		fp += " assigned"
 	}
 
 	if c == 0 && n.Used != 0 {
@@ -820,10 +820,10 @@
 
 	case TUNSAFEPTR:
 		if fmtmode == FExp {
-			fp += fmt.Sprintf("@\"unsafe\".Pointer")
+			fp += "@\"unsafe\".Pointer"
 			return fp
 		}
-		fp += fmt.Sprintf("unsafe.Pointer")
+		fp += "unsafe.Pointer"
 		return fp
 	}
 
@@ -1184,7 +1184,7 @@
 
 	case ODDDARG:
 		var f string
-		f += fmt.Sprintf("... argument")
+		f += "... argument"
 		return f
 
 	case OREGISTER:
@@ -1217,7 +1217,7 @@
 	// _ becomes ~b%d internally; print as _ for export
 	case ONAME:
 		if fmtmode == FExp && n.Sym != nil && n.Sym.Name[0] == '~' && n.Sym.Name[1] == 'b' {
-			return fmt.Sprintf("_")
+			return "_"
 		}
 		if fmtmode == FExp && n.Sym != nil && !isblank(n) && n.Vargen > 0 {
 			return fmt.Sprintf("%v·%d", Sconv(n.Sym, 0), n.Vargen)
@@ -1286,17 +1286,17 @@
 
 	case OTSTRUCT:
 		var f string
-		f += fmt.Sprintf("<struct>")
+		f += "<struct>"
 		return f
 
 	case OTINTER:
 		var f string
-		f += fmt.Sprintf("<inter>")
+		f += "<inter>"
 		return f
 
 	case OTFUNC:
 		var f string
-		f += fmt.Sprintf("<func>")
+		f += "<func>"
 		return f
 
 	case OCLOSURE:
@@ -1565,7 +1565,7 @@
 		var f string
 		for l := n.List; l != nil; l = l.Next {
 			if l != n.List {
-				f += fmt.Sprintf(" + ")
+				f += " + "
 			}
 			f += exprfmt(l.N, nprec)
 		}
@@ -1596,7 +1596,7 @@
 
 	if flag&obj.FmtLong != 0 /*untyped*/ && t != nil {
 		if t.Etype == TNIL {
-			return fmt.Sprintf("nil")
+			return "nil"
 		} else {
 			return fmt.Sprintf("%v (type %v)", Nconv(n, 0), Tconv(t, 0))
 		}
diff --git a/src/cmd/internal/gc/init.go b/src/cmd/internal/gc/init.go
index a7d4fbd..3c27bd6 100644
--- a/src/cmd/internal/gc/init.go
+++ b/src/cmd/internal/gc/init.go
@@ -118,7 +118,7 @@
 	r := (*NodeList)(nil)
 
 	// (1)
-	namebuf = fmt.Sprintf("initdone·")
+	namebuf = "initdone·"
 
 	gatevar := newname(Lookup(namebuf))
 	addvar(gatevar, Types[TUINT8], PEXTERN)
@@ -126,7 +126,7 @@
 	// (2)
 	Maxarg = 0
 
-	namebuf = fmt.Sprintf("init")
+	namebuf = "init"
 
 	fn := Nod(ODCLFUNC, nil, nil)
 	initsym := Lookup(namebuf)
diff --git a/src/cmd/internal/gc/mparith1.go b/src/cmd/internal/gc/mparith1.go
index ee309e4..104992f 100644
--- a/src/cmd/internal/gc/mparith1.go
+++ b/src/cmd/internal/gc/mparith1.go
@@ -608,7 +608,7 @@
 		if -900 < exp && exp < 900 {
 			d := mpgetflt(fvp)
 			if d >= 0 && (flag&obj.FmtSign != 0 /*untyped*/) {
-				fp += fmt.Sprintf("+")
+				fp += "+"
 			}
 			fp += fmt.Sprintf("%.6g", d)
 			return fp
@@ -632,9 +632,9 @@
 		}
 
 		if fvp.Val.Neg != 0 {
-			fp += fmt.Sprintf("-")
+			fp += "-"
 		} else if flag&obj.FmtSign != 0 /*untyped*/ {
-			fp += fmt.Sprintf("+")
+			fp += "+"
 		}
 		fp += fmt.Sprintf("%.5fe+%d", d, exp)
 		return fp
@@ -643,7 +643,7 @@
 	var fv Mpflt
 	var buf string
 	if sigfig(fvp) == 0 {
-		buf = fmt.Sprintf("0p+0")
+		buf = "0p+0"
 		goto out
 	}
 
diff --git a/src/cmd/internal/gc/plive.go b/src/cmd/internal/gc/plive.go
index 99654c5..86e7ea0 100644
--- a/src/cmd/internal/gc/plive.go
+++ b/src/cmd/internal/gc/plive.go
@@ -1475,7 +1475,7 @@
 					if p.As == obj.ACALL && p.To.Node != nil {
 						fmt_ += fmt.Sprintf("call to %s:", ((p.To.Node).(*Node)).Sym.Name)
 					} else if p.As == obj.ACALL {
-						fmt_ += fmt.Sprintf("indirect call:")
+						fmt_ += "indirect call:"
 					} else {
 						fmt_ += fmt.Sprintf("entry to %s:", ((p.From.Node).(*Node)).Sym.Name)
 					}
@@ -1488,7 +1488,7 @@
 						}
 					}
 
-					fmt_ += fmt.Sprintf("\n")
+					fmt_ += "\n"
 					if numlive == 0 { // squelch message
 
 					} else {
diff --git a/src/cmd/internal/gc/subr.go b/src/cmd/internal/gc/subr.go
index 998b3e7..1c59e59 100644
--- a/src/cmd/internal/gc/subr.go
+++ b/src/cmd/internal/gc/subr.go
@@ -1729,9 +1729,9 @@
 	// common mistake: *struct and *interface.
 	if tl != nil && tr != nil && Isptr[tl.Etype] != 0 && Isptr[tr.Etype] != 0 {
 		if tl.Type.Etype == TSTRUCT && tr.Type.Etype == TINTER {
-			fmt_ += fmt.Sprintf("\n\t(*struct vs *interface)")
+			fmt_ += "\n\t(*struct vs *interface)"
 		} else if tl.Type.Etype == TINTER && tr.Type.Etype == TSTRUCT {
-			fmt_ += fmt.Sprintf("\n\t(*interface vs *struct)")
+			fmt_ += "\n\t(*interface vs *struct)"
 		}
 	}
 
diff --git a/src/cmd/internal/gc/walk.go b/src/cmd/internal/gc/walk.go
index b242fd4..c57bdd6 100644
--- a/src/cmd/internal/gc/walk.go
+++ b/src/cmd/internal/gc/walk.go
@@ -1796,13 +1796,13 @@
 	var savel Iter
 
 	fmt_ := ""
-	fmt_ += fmt.Sprintf("\t")
+	fmt_ += "\t"
 	first := 1
 	for l := Structfirst(&savel, nl); l != nil; l = structnext(&savel) {
 		if first != 0 {
 			first = 0
 		} else {
-			fmt_ += fmt.Sprintf(", ")
+			fmt_ += ", "
 		}
 		fmt_ += fmt.Sprintf("%v", Tconv(l, 0))
 	}
@@ -1817,14 +1817,14 @@
 	var r *Node
 
 	fmt_ := ""
-	fmt_ += fmt.Sprintf("\t")
+	fmt_ += "\t"
 	first := 1
 	for ; l != nil; l = l.Next {
 		r = l.N
 		if first != 0 {
 			first = 0
 		} else {
-			fmt_ += fmt.Sprintf(", ")
+			fmt_ += ", "
 		}
 		fmt_ += fmt.Sprintf("%v", Tconv(r.Type, 0))
 	}