diff --git a/src/cmd/compile/internal/ssa/gen/ARM.rules b/src/cmd/compile/internal/ssa/gen/ARM.rules
index f46f4238f7..5c6438a986 100644
--- a/src/cmd/compile/internal/ssa/gen/ARM.rules
+++ b/src/cmd/compile/internal/ssa/gen/ARM.rules
@@ -173,7 +173,7 @@
 (Const(8|16|32) [val]) => (MOVWconst [int32(val)])
 (Const(32|64)F [val]) => (MOV(F|D)const [float64(val)])
 (ConstNil) => (MOVWconst [0])
-(ConstBool [b]) => (MOVWconst [b2i32(b)])
+(ConstBool [t]) => (MOVWconst [b2i32(t)])
 
 // truncations
 // Because we ignore high parts of registers, truncates are just copies.
diff --git a/src/cmd/compile/internal/ssa/gen/ARM64.rules b/src/cmd/compile/internal/ssa/gen/ARM64.rules
index 6f30c11bd1..7f9f8298de 100644
--- a/src/cmd/compile/internal/ssa/gen/ARM64.rules
+++ b/src/cmd/compile/internal/ssa/gen/ARM64.rules
@@ -198,7 +198,7 @@
 (Const(64|32|16|8) [val]) => (MOVDconst [int64(val)])
 (Const(32F|64F) [val]) => (FMOV(S|D)const [float64(val)])
 (ConstNil) => (MOVDconst [0])
-(ConstBool [b]) => (MOVDconst [b2i(b)])
+(ConstBool [t]) => (MOVDconst [b2i(t)])
 
 (Slicemask <t> x) => (SRAconst (NEG <t> x) [63])
 
diff --git a/src/cmd/compile/internal/ssa/gen/MIPS.rules b/src/cmd/compile/internal/ssa/gen/MIPS.rules
index 6b59555cbe..4ac9668ea9 100644
--- a/src/cmd/compile/internal/ssa/gen/MIPS.rules
+++ b/src/cmd/compile/internal/ssa/gen/MIPS.rules
@@ -144,7 +144,7 @@
 (Const(32|16|8) [val]) => (MOVWconst [int32(val)])
 (Const(32|64)F ...) => (MOV(F|D)const ...)
 (ConstNil) => (MOVWconst [0])
-(ConstBool [b]) => (MOVWconst [b2i32(b)])
+(ConstBool [t]) => (MOVWconst [b2i32(t)])
 
 // truncations
 // Because we ignore high parts of registers, truncates are just copies.
diff --git a/src/cmd/compile/internal/ssa/gen/MIPS64.rules b/src/cmd/compile/internal/ssa/gen/MIPS64.rules
index bb91dcd5ee..fd04a6c3a8 100644
--- a/src/cmd/compile/internal/ssa/gen/MIPS64.rules
+++ b/src/cmd/compile/internal/ssa/gen/MIPS64.rules
@@ -134,7 +134,7 @@
 (Const(64|32|16|8) [val]) => (MOVVconst [int64(val)])
 (Const(32|64)F [val]) => (MOV(F|D)const [float64(val)])
 (ConstNil) => (MOVVconst [0])
-(ConstBool [b]) => (MOVVconst [int64(b2i(b))])
+(ConstBool [t]) => (MOVVconst [int64(b2i(t))])
 
 (Slicemask <t> x) => (SRAVconst (NEGV <t> x) [63])
 
diff --git a/src/cmd/compile/internal/ssa/gen/PPC64.rules b/src/cmd/compile/internal/ssa/gen/PPC64.rules
index b618cde529..f83ff75761 100644
--- a/src/cmd/compile/internal/ssa/gen/PPC64.rules
+++ b/src/cmd/compile/internal/ssa/gen/PPC64.rules
@@ -101,7 +101,7 @@
 (Const(64|32|16|8) [val]) => (MOVDconst [int64(val)])
 (Const(32|64)F ...) => (FMOV(S|D)const ...)
 (ConstNil) => (MOVDconst [0])
-(ConstBool [b]) => (MOVDconst [b2i(b)])
+(ConstBool [t]) => (MOVDconst [b2i(t)])
 
 // Constant folding
 (FABS (FMOVDconst [x])) => (FMOVDconst [math.Abs(x)])
diff --git a/src/cmd/compile/internal/ssa/gen/S390X.rules b/src/cmd/compile/internal/ssa/gen/S390X.rules
index 0fdd231d71..88762f7045 100644
--- a/src/cmd/compile/internal/ssa/gen/S390X.rules
+++ b/src/cmd/compile/internal/ssa/gen/S390X.rules
@@ -428,7 +428,7 @@
 (Const(64|32|16|8) [val]) => (MOVDconst [int64(val)])
 (Const(32|64)F ...) => (FMOV(S|D)const ...)
 (ConstNil) => (MOVDconst [0])
-(ConstBool [b]) => (MOVDconst [b2i(b)])
+(ConstBool [t]) => (MOVDconst [b2i(t)])
 
 // Lowering calls
 (StaticCall ...) => (CALLstatic ...)
diff --git a/src/cmd/compile/internal/ssa/gen/generic.rules b/src/cmd/compile/internal/ssa/gen/generic.rules
index 9dd20a7cfa..6b5fd99c7e 100644
--- a/src/cmd/compile/internal/ssa/gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/gen/generic.rules
@@ -768,7 +768,7 @@
 	=> mem
 
 // Collapse OffPtr
-(OffPtr (OffPtr p [b]) [a]) => (OffPtr p [a+b])
+(OffPtr (OffPtr p [y]) [x]) => (OffPtr p [x+y])
 (OffPtr p [0]) && v.Type.Compare(p.Type) == types.CMPeq => p
 
 // indexing operations
@@ -847,7 +847,7 @@
             f0 mem))))
 
 // Putting struct{*byte} and similar into direct interfaces.
-(IMake typ (StructMake1 val)) => (IMake typ val)
+(IMake _typ (StructMake1 val)) => (IMake _typ val)
 (StructSelect [0] (IData x)) => (IData x)
 
 // un-SSAable values use mem->mem copies
@@ -869,7 +869,7 @@
 (Store dst (ArrayMake1 e) mem) => (Store {e.Type} dst e mem)
 
 // Putting [1]*byte and similar into direct interfaces.
-(IMake typ (ArrayMake1 val)) => (IMake typ val)
+(IMake _typ (ArrayMake1 val)) => (IMake _typ val)
 (ArraySelect [0] (IData x)) => (IData x)
 
 // string ops
@@ -1974,9 +1974,9 @@
 (Sqrt (Const64F [c])) && !math.IsNaN(math.Sqrt(c)) => (Const64F [math.Sqrt(c)])
 
 // for rewriting results of some late-expanded rewrites (below)
-(SelectN [0] (MakeResult a ___)) => a
-(SelectN [1] (MakeResult a b ___)) => b
-(SelectN [2] (MakeResult a b c ___)) => c
+(SelectN [0] (MakeResult x ___)) => x
+(SelectN [1] (MakeResult x y ___)) => y
+(SelectN [2] (MakeResult x y z ___)) => z
 
 // for late-expanded calls, recognize newobject and remove zeroing and nilchecks
 (Zero (SelectN [0] call:(StaticLECall _ _)) mem:(SelectN [1] call))
@@ -2013,18 +2013,18 @@
 // Evaluate constant address comparisons.
 (EqPtr  x x) => (ConstBool [true])
 (NeqPtr x x) => (ConstBool [false])
-(EqPtr  (Addr {a} _) (Addr {b} _)) => (ConstBool [a == b])
-(EqPtr  (Addr {a} _) (OffPtr [o] (Addr {b} _))) => (ConstBool [a == b && o == 0])
-(EqPtr  (OffPtr [o1] (Addr {a} _)) (OffPtr [o2] (Addr {b} _))) => (ConstBool [a == b && o1 == o2])
-(NeqPtr (Addr {a} _) (Addr {b} _)) => (ConstBool [a != b])
-(NeqPtr (Addr {a} _) (OffPtr [o] (Addr {b} _))) => (ConstBool [a != b || o != 0])
-(NeqPtr (OffPtr [o1] (Addr {a} _)) (OffPtr [o2] (Addr {b} _))) => (ConstBool [a != b || o1 != o2])
-(EqPtr  (LocalAddr {a} _ _) (LocalAddr {b} _ _)) => (ConstBool [a == b])
-(EqPtr  (LocalAddr {a} _ _) (OffPtr [o] (LocalAddr {b} _ _))) => (ConstBool [a == b && o == 0])
-(EqPtr  (OffPtr [o1] (LocalAddr {a} _ _)) (OffPtr [o2] (LocalAddr {b} _ _))) => (ConstBool [a == b && o1 == o2])
-(NeqPtr (LocalAddr {a} _ _) (LocalAddr {b} _ _)) => (ConstBool [a != b])
-(NeqPtr (LocalAddr {a} _ _) (OffPtr [o] (LocalAddr {b} _ _))) => (ConstBool [a != b || o != 0])
-(NeqPtr (OffPtr [o1] (LocalAddr {a} _ _)) (OffPtr [o2] (LocalAddr {b} _ _))) => (ConstBool [a != b || o1 != o2])
+(EqPtr  (Addr {x} _) (Addr {y} _)) => (ConstBool [x == y])
+(EqPtr  (Addr {x} _) (OffPtr [o] (Addr {y} _))) => (ConstBool [x == y && o == 0])
+(EqPtr  (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _))) => (ConstBool [x == y && o1 == o2])
+(NeqPtr (Addr {x} _) (Addr {y} _)) => (ConstBool [x != y])
+(NeqPtr (Addr {x} _) (OffPtr [o] (Addr {y} _))) => (ConstBool [x != y || o != 0])
+(NeqPtr (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _))) => (ConstBool [x != y || o1 != o2])
+(EqPtr  (LocalAddr {x} _ _) (LocalAddr {y} _ _)) => (ConstBool [x == y])
+(EqPtr  (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _))) => (ConstBool [x == y && o == 0])
+(EqPtr  (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _))) => (ConstBool [x == y && o1 == o2])
+(NeqPtr (LocalAddr {x} _ _) (LocalAddr {y} _ _)) => (ConstBool [x != y])
+(NeqPtr (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _))) => (ConstBool [x != y || o != 0])
+(NeqPtr (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _))) => (ConstBool [x != y || o1 != o2])
 (EqPtr  (OffPtr [o1] p1) p2) && isSamePtr(p1, p2) => (ConstBool [o1 == 0])
 (NeqPtr (OffPtr [o1] p1) p2) && isSamePtr(p1, p2) => (ConstBool [o1 != 0])
 (EqPtr  (OffPtr [o1] p1) (OffPtr [o2] p2)) && isSamePtr(p1, p2) => (ConstBool [o1 == o2])
diff --git a/src/cmd/compile/internal/ssa/gen/rulegen.go b/src/cmd/compile/internal/ssa/gen/rulegen.go
index a3ce726dc3..fd672b2f74 100644
--- a/src/cmd/compile/internal/ssa/gen/rulegen.go
+++ b/src/cmd/compile/internal/ssa/gen/rulegen.go
@@ -218,10 +218,10 @@ func genRulesSuffix(arch arch, suff string) {
 			Suffix: fmt.Sprintf("_%s", op),
 			ArgLen: opByName(arch, op).argLength,
 		}
-		fn.add(declf("b", "v.Block"))
-		fn.add(declf("config", "b.Func.Config"))
-		fn.add(declf("fe", "b.Func.fe"))
-		fn.add(declf("typ", "&b.Func.Config.Types"))
+		fn.add(declReserved("b", "v.Block"))
+		fn.add(declReserved("config", "b.Func.Config"))
+		fn.add(declReserved("fe", "b.Func.fe"))
+		fn.add(declReserved("typ", "&b.Func.Config.Types"))
 		for _, rule := range rules {
 			if rr != nil && !rr.CanFail {
 				log.Fatalf("unconditional rule %s is followed by other rules", rr.Match)
@@ -250,8 +250,8 @@ func genRulesSuffix(arch arch, suff string) {
 	// Generate block rewrite function. There are only a few block types
 	// so we can make this one function with a switch.
 	fn = &Func{Kind: "Block"}
-	fn.add(declf("config", "b.Func.Config"))
-	fn.add(declf("typ", "&b.Func.Config.Types"))
+	fn.add(declReserved("config", "b.Func.Config"))
+	fn.add(declReserved("typ", "&b.Func.Config.Types"))
 
 	sw = &Switch{Expr: exprf("b.Kind")}
 	ops = ops[:0]
@@ -828,12 +828,36 @@ func stmtf(format string, a ...interface{}) Statement {
 	return file.Decls[0].(*ast.FuncDecl).Body.List[0]
 }
 
-// declf constructs a simple "name := value" declaration, using exprf for its
-// value.
-func declf(name, format string, a ...interface{}) *Declare {
+var reservedNames = map[string]bool{
+	"v":      true, // Values[i], etc
+	"b":      true, // v.Block
+	"config": true, // b.Func.Config
+	"fe":     true, // b.Func.fe
+	"typ":    true, // &b.Func.Config.Types
+}
+
+// declf constructs a simple "name := value" declaration,
+// using exprf for its value.
+//
+// name must not be one of reservedNames.
+// This helps prevent unintended shadowing and name clashes.
+// To declare a reserved name, use declReserved.
+func declf(loc, name, format string, a ...interface{}) *Declare {
+	if reservedNames[name] {
+		log.Fatalf("rule %s uses the reserved name %s", loc, name)
+	}
 	return &Declare{name, exprf(format, a...)}
 }
 
+// declReserved is like declf, but the name must be one of reservedNames.
+// Calls to declReserved should generally be static and top-level.
+func declReserved(name, value string) *Declare {
+	if !reservedNames[name] {
+		panic(fmt.Sprintf("declReserved call does not use a reserved name: %q", name))
+	}
+	return &Declare{name, exprf(value)}
+}
+
 // breakf constructs a simple "if cond { break }" statement, using exprf for its
 // condition.
 func breakf(format string, a ...interface{}) *CondBreak {
@@ -858,7 +882,7 @@ func genBlockRewrite(rule Rule, arch arch, data blockData) *RuleRewrite {
 			if vname == "" {
 				vname = fmt.Sprintf("v_%v", i)
 			}
-			rr.add(declf(vname, cname))
+			rr.add(declf(rr.Loc, vname, cname))
 			p, op := genMatch0(rr, arch, expr, vname, nil, false) // TODO: pass non-nil cnt?
 			if op != "" {
 				check := fmt.Sprintf("%s.Op == %s", cname, op)
@@ -873,7 +897,7 @@ func genBlockRewrite(rule Rule, arch arch, data blockData) *RuleRewrite {
 			}
 			pos[i] = p
 		} else {
-			rr.add(declf(arg, cname))
+			rr.add(declf(rr.Loc, arg, cname))
 			pos[i] = arg + ".Pos"
 		}
 	}
@@ -893,7 +917,7 @@ func genBlockRewrite(rule Rule, arch arch, data blockData) *RuleRewrite {
 		if !token.IsIdentifier(e.name) || rr.declared(e.name) {
 			rr.add(breakf("%sTo%s(b.%s) != %s", unTitle(e.field), title(e.dclType), e.field, e.name))
 		} else {
-			rr.add(declf(e.name, "%sTo%s(b.%s)", unTitle(e.field), title(e.dclType), e.field))
+			rr.add(declf(rr.Loc, e.name, "%sTo%s(b.%s)", unTitle(e.field), title(e.dclType), e.field))
 		}
 	}
 	if rr.Cond != "" {
@@ -1043,11 +1067,11 @@ func genMatch0(rr *RuleRewrite, arch arch, match, v string, cnt map[string]int,
 		} else {
 			switch e.field {
 			case "Aux":
-				rr.add(declf(e.name, "auxTo%s(%s.%s)", title(e.dclType), v, e.field))
+				rr.add(declf(rr.Loc, e.name, "auxTo%s(%s.%s)", title(e.dclType), v, e.field))
 			case "AuxInt":
-				rr.add(declf(e.name, "auxIntTo%s(%s.%s)", title(e.dclType), v, e.field))
+				rr.add(declf(rr.Loc, e.name, "auxIntTo%s(%s.%s)", title(e.dclType), v, e.field))
 			case "Type":
-				rr.add(declf(e.name, "%s.%s", v, e.field))
+				rr.add(declf(rr.Loc, e.name, "%s.%s", v, e.field))
 			}
 		}
 	}
@@ -1077,7 +1101,7 @@ func genMatch0(rr *RuleRewrite, arch arch, match, v string, cnt map[string]int,
 				continue
 			}
 			if !rr.declared(a) && token.IsIdentifier(a) && !(commutative && len(args) == 2) {
-				rr.add(declf(a, "%s.Args[%d]", v, n))
+				rr.add(declf(rr.Loc, a, "%s.Args[%d]", v, n))
 				// delete the last argument so it is not reprocessed
 				args = args[:n]
 			} else {
@@ -1089,7 +1113,7 @@ func genMatch0(rr *RuleRewrite, arch arch, match, v string, cnt map[string]int,
 	if commutative && !pregenTop {
 		for i := 0; i <= 1; i++ {
 			vname := fmt.Sprintf("%s_%d", v, i)
-			rr.add(declf(vname, "%s.Args[%d]", v, i))
+			rr.add(declf(rr.Loc, vname, "%s.Args[%d]", v, i))
 		}
 	}
 	if commutative {
@@ -1116,7 +1140,7 @@ func genMatch0(rr *RuleRewrite, arch arch, match, v string, cnt map[string]int,
 				rr.add(breakf("%s != %s", arg, rhs))
 			} else {
 				if arg != rhs {
-					rr.add(declf(arg, "%s", rhs))
+					rr.add(declf(rr.Loc, arg, "%s", rhs))
 				}
 			}
 			continue
@@ -1131,7 +1155,7 @@ func genMatch0(rr *RuleRewrite, arch arch, match, v string, cnt map[string]int,
 		}
 
 		if argname != rhs {
-			rr.add(declf(argname, "%s", rhs))
+			rr.add(declf(rr.Loc, argname, "%s", rhs))
 		}
 		bexpr := exprf("%s.Op != addLater", argname)
 		rr.add(&CondBreak{Cond: bexpr})
@@ -1208,7 +1232,7 @@ func genResult0(rr *RuleRewrite, arch arch, result string, top, move bool, pos s
 			v = resname
 		}
 		rr.Alloc++
-		rr.add(declf(v, "b.NewValue0(%s, Op%s%s, %s)", pos, oparch, op.name, typ))
+		rr.add(declf(rr.Loc, v, "b.NewValue0(%s, Op%s%s, %s)", pos, oparch, op.name, typ))
 		if move && top {
 			// Rewrite original into a copy
 			rr.add(stmtf("v.copyOf(%s)", v))
diff --git a/src/cmd/compile/internal/ssa/rewriteARM.go b/src/cmd/compile/internal/ssa/rewriteARM.go
index ed1f85e340..175bbc3e7e 100644
--- a/src/cmd/compile/internal/ssa/rewriteARM.go
+++ b/src/cmd/compile/internal/ssa/rewriteARM.go
@@ -13031,12 +13031,12 @@ func rewriteValueARM_OpConst8(v *Value) bool {
 	}
 }
 func rewriteValueARM_OpConstBool(v *Value) bool {
-	// match: (ConstBool [b])
-	// result: (MOVWconst [b2i32(b)])
+	// match: (ConstBool [t])
+	// result: (MOVWconst [b2i32(t)])
 	for {
-		b := auxIntToBool(v.AuxInt)
+		t := auxIntToBool(v.AuxInt)
 		v.reset(OpARMMOVWconst)
-		v.AuxInt = int32ToAuxInt(b2i32(b))
+		v.AuxInt = int32ToAuxInt(b2i32(t))
 		return true
 	}
 }
diff --git a/src/cmd/compile/internal/ssa/rewriteARM64.go b/src/cmd/compile/internal/ssa/rewriteARM64.go
index da80ad6fca..eb650b6a50 100644
--- a/src/cmd/compile/internal/ssa/rewriteARM64.go
+++ b/src/cmd/compile/internal/ssa/rewriteARM64.go
@@ -22253,12 +22253,12 @@ func rewriteValueARM64_OpConst8(v *Value) bool {
 	}
 }
 func rewriteValueARM64_OpConstBool(v *Value) bool {
-	// match: (ConstBool [b])
-	// result: (MOVDconst [b2i(b)])
+	// match: (ConstBool [t])
+	// result: (MOVDconst [b2i(t)])
 	for {
-		b := auxIntToBool(v.AuxInt)
+		t := auxIntToBool(v.AuxInt)
 		v.reset(OpARM64MOVDconst)
-		v.AuxInt = int64ToAuxInt(b2i(b))
+		v.AuxInt = int64ToAuxInt(b2i(t))
 		return true
 	}
 }
diff --git a/src/cmd/compile/internal/ssa/rewriteMIPS.go b/src/cmd/compile/internal/ssa/rewriteMIPS.go
index fdf329cbd0..429369d631 100644
--- a/src/cmd/compile/internal/ssa/rewriteMIPS.go
+++ b/src/cmd/compile/internal/ssa/rewriteMIPS.go
@@ -872,12 +872,12 @@ func rewriteValueMIPS_OpConst8(v *Value) bool {
 	}
 }
 func rewriteValueMIPS_OpConstBool(v *Value) bool {
-	// match: (ConstBool [b])
-	// result: (MOVWconst [b2i32(b)])
+	// match: (ConstBool [t])
+	// result: (MOVWconst [b2i32(t)])
 	for {
-		b := auxIntToBool(v.AuxInt)
+		t := auxIntToBool(v.AuxInt)
 		v.reset(OpMIPSMOVWconst)
-		v.AuxInt = int32ToAuxInt(b2i32(b))
+		v.AuxInt = int32ToAuxInt(b2i32(t))
 		return true
 	}
 }
diff --git a/src/cmd/compile/internal/ssa/rewriteMIPS64.go b/src/cmd/compile/internal/ssa/rewriteMIPS64.go
index 79da4dfb72..772d7b66ef 100644
--- a/src/cmd/compile/internal/ssa/rewriteMIPS64.go
+++ b/src/cmd/compile/internal/ssa/rewriteMIPS64.go
@@ -835,12 +835,12 @@ func rewriteValueMIPS64_OpConst8(v *Value) bool {
 	}
 }
 func rewriteValueMIPS64_OpConstBool(v *Value) bool {
-	// match: (ConstBool [b])
-	// result: (MOVVconst [int64(b2i(b))])
+	// match: (ConstBool [t])
+	// result: (MOVVconst [int64(b2i(t))])
 	for {
-		b := auxIntToBool(v.AuxInt)
+		t := auxIntToBool(v.AuxInt)
 		v.reset(OpMIPS64MOVVconst)
-		v.AuxInt = int64ToAuxInt(int64(b2i(b)))
+		v.AuxInt = int64ToAuxInt(int64(b2i(t)))
 		return true
 	}
 }
diff --git a/src/cmd/compile/internal/ssa/rewritePPC64.go b/src/cmd/compile/internal/ssa/rewritePPC64.go
index a5bbc836cc..f181d433cc 100644
--- a/src/cmd/compile/internal/ssa/rewritePPC64.go
+++ b/src/cmd/compile/internal/ssa/rewritePPC64.go
@@ -1234,12 +1234,12 @@ func rewriteValuePPC64_OpConst8(v *Value) bool {
 	}
 }
 func rewriteValuePPC64_OpConstBool(v *Value) bool {
-	// match: (ConstBool [b])
-	// result: (MOVDconst [b2i(b)])
+	// match: (ConstBool [t])
+	// result: (MOVDconst [b2i(t)])
 	for {
-		b := auxIntToBool(v.AuxInt)
+		t := auxIntToBool(v.AuxInt)
 		v.reset(OpPPC64MOVDconst)
-		v.AuxInt = int64ToAuxInt(b2i(b))
+		v.AuxInt = int64ToAuxInt(b2i(t))
 		return true
 	}
 }
diff --git a/src/cmd/compile/internal/ssa/rewriteS390X.go b/src/cmd/compile/internal/ssa/rewriteS390X.go
index f02362a0d4..8b41d62c31 100644
--- a/src/cmd/compile/internal/ssa/rewriteS390X.go
+++ b/src/cmd/compile/internal/ssa/rewriteS390X.go
@@ -1321,12 +1321,12 @@ func rewriteValueS390X_OpConst8(v *Value) bool {
 	}
 }
 func rewriteValueS390X_OpConstBool(v *Value) bool {
-	// match: (ConstBool [b])
-	// result: (MOVDconst [b2i(b)])
+	// match: (ConstBool [t])
+	// result: (MOVDconst [b2i(t)])
 	for {
-		b := auxIntToBool(v.AuxInt)
+		t := auxIntToBool(v.AuxInt)
 		v.reset(OpS390XMOVDconst)
-		v.AuxInt = int64ToAuxInt(b2i(b))
+		v.AuxInt = int64ToAuxInt(b2i(t))
 		return true
 	}
 }
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 7e7cf458ff..535fc8916d 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -8152,32 +8152,32 @@ func rewriteValuegeneric_OpEqPtr(v *Value) bool {
 		v.AuxInt = boolToAuxInt(true)
 		return true
 	}
-	// match: (EqPtr (Addr {a} _) (Addr {b} _))
-	// result: (ConstBool [a == b])
+	// match: (EqPtr (Addr {x} _) (Addr {y} _))
+	// result: (ConstBool [x == y])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpAddr {
 				continue
 			}
-			a := auxToSym(v_0.Aux)
+			x := auxToSym(v_0.Aux)
 			if v_1.Op != OpAddr {
 				continue
 			}
-			b := auxToSym(v_1.Aux)
+			y := auxToSym(v_1.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a == b)
+			v.AuxInt = boolToAuxInt(x == y)
 			return true
 		}
 		break
 	}
-	// match: (EqPtr (Addr {a} _) (OffPtr [o] (Addr {b} _)))
-	// result: (ConstBool [a == b && o == 0])
+	// match: (EqPtr (Addr {x} _) (OffPtr [o] (Addr {y} _)))
+	// result: (ConstBool [x == y && o == 0])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpAddr {
 				continue
 			}
-			a := auxToSym(v_0.Aux)
+			x := auxToSym(v_0.Aux)
 			if v_1.Op != OpOffPtr {
 				continue
 			}
@@ -8186,15 +8186,15 @@ func rewriteValuegeneric_OpEqPtr(v *Value) bool {
 			if v_1_0.Op != OpAddr {
 				continue
 			}
-			b := auxToSym(v_1_0.Aux)
+			y := auxToSym(v_1_0.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a == b && o == 0)
+			v.AuxInt = boolToAuxInt(x == y && o == 0)
 			return true
 		}
 		break
 	}
-	// match: (EqPtr (OffPtr [o1] (Addr {a} _)) (OffPtr [o2] (Addr {b} _)))
-	// result: (ConstBool [a == b && o1 == o2])
+	// match: (EqPtr (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _)))
+	// result: (ConstBool [x == y && o1 == o2])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpOffPtr {
@@ -8205,7 +8205,7 @@ func rewriteValuegeneric_OpEqPtr(v *Value) bool {
 			if v_0_0.Op != OpAddr {
 				continue
 			}
-			a := auxToSym(v_0_0.Aux)
+			x := auxToSym(v_0_0.Aux)
 			if v_1.Op != OpOffPtr {
 				continue
 			}
@@ -8214,39 +8214,39 @@ func rewriteValuegeneric_OpEqPtr(v *Value) bool {
 			if v_1_0.Op != OpAddr {
 				continue
 			}
-			b := auxToSym(v_1_0.Aux)
+			y := auxToSym(v_1_0.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a == b && o1 == o2)
+			v.AuxInt = boolToAuxInt(x == y && o1 == o2)
 			return true
 		}
 		break
 	}
-	// match: (EqPtr (LocalAddr {a} _ _) (LocalAddr {b} _ _))
-	// result: (ConstBool [a == b])
+	// match: (EqPtr (LocalAddr {x} _ _) (LocalAddr {y} _ _))
+	// result: (ConstBool [x == y])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpLocalAddr {
 				continue
 			}
-			a := auxToSym(v_0.Aux)
+			x := auxToSym(v_0.Aux)
 			if v_1.Op != OpLocalAddr {
 				continue
 			}
-			b := auxToSym(v_1.Aux)
+			y := auxToSym(v_1.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a == b)
+			v.AuxInt = boolToAuxInt(x == y)
 			return true
 		}
 		break
 	}
-	// match: (EqPtr (LocalAddr {a} _ _) (OffPtr [o] (LocalAddr {b} _ _)))
-	// result: (ConstBool [a == b && o == 0])
+	// match: (EqPtr (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _)))
+	// result: (ConstBool [x == y && o == 0])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpLocalAddr {
 				continue
 			}
-			a := auxToSym(v_0.Aux)
+			x := auxToSym(v_0.Aux)
 			if v_1.Op != OpOffPtr {
 				continue
 			}
@@ -8255,15 +8255,15 @@ func rewriteValuegeneric_OpEqPtr(v *Value) bool {
 			if v_1_0.Op != OpLocalAddr {
 				continue
 			}
-			b := auxToSym(v_1_0.Aux)
+			y := auxToSym(v_1_0.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a == b && o == 0)
+			v.AuxInt = boolToAuxInt(x == y && o == 0)
 			return true
 		}
 		break
 	}
-	// match: (EqPtr (OffPtr [o1] (LocalAddr {a} _ _)) (OffPtr [o2] (LocalAddr {b} _ _)))
-	// result: (ConstBool [a == b && o1 == o2])
+	// match: (EqPtr (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _)))
+	// result: (ConstBool [x == y && o1 == o2])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpOffPtr {
@@ -8274,7 +8274,7 @@ func rewriteValuegeneric_OpEqPtr(v *Value) bool {
 			if v_0_0.Op != OpLocalAddr {
 				continue
 			}
-			a := auxToSym(v_0_0.Aux)
+			x := auxToSym(v_0_0.Aux)
 			if v_1.Op != OpOffPtr {
 				continue
 			}
@@ -8283,9 +8283,9 @@ func rewriteValuegeneric_OpEqPtr(v *Value) bool {
 			if v_1_0.Op != OpLocalAddr {
 				continue
 			}
-			b := auxToSym(v_1_0.Aux)
+			y := auxToSym(v_1_0.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a == b && o1 == o2)
+			v.AuxInt = boolToAuxInt(x == y && o1 == o2)
 			return true
 		}
 		break
@@ -8532,28 +8532,28 @@ func rewriteValuegeneric_OpEqSlice(v *Value) bool {
 func rewriteValuegeneric_OpIMake(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
-	// match: (IMake typ (StructMake1 val))
-	// result: (IMake typ val)
+	// match: (IMake _typ (StructMake1 val))
+	// result: (IMake _typ val)
 	for {
-		typ := v_0
+		_typ := v_0
 		if v_1.Op != OpStructMake1 {
 			break
 		}
 		val := v_1.Args[0]
 		v.reset(OpIMake)
-		v.AddArg2(typ, val)
+		v.AddArg2(_typ, val)
 		return true
 	}
-	// match: (IMake typ (ArrayMake1 val))
-	// result: (IMake typ val)
+	// match: (IMake _typ (ArrayMake1 val))
+	// result: (IMake _typ val)
 	for {
-		typ := v_0
+		_typ := v_0
 		if v_1.Op != OpArrayMake1 {
 			break
 		}
 		val := v_1.Args[0]
 		v.reset(OpIMake)
-		v.AddArg2(typ, val)
+		v.AddArg2(_typ, val)
 		return true
 	}
 	return false
@@ -15710,32 +15710,32 @@ func rewriteValuegeneric_OpNeqPtr(v *Value) bool {
 		v.AuxInt = boolToAuxInt(false)
 		return true
 	}
-	// match: (NeqPtr (Addr {a} _) (Addr {b} _))
-	// result: (ConstBool [a != b])
+	// match: (NeqPtr (Addr {x} _) (Addr {y} _))
+	// result: (ConstBool [x != y])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpAddr {
 				continue
 			}
-			a := auxToSym(v_0.Aux)
+			x := auxToSym(v_0.Aux)
 			if v_1.Op != OpAddr {
 				continue
 			}
-			b := auxToSym(v_1.Aux)
+			y := auxToSym(v_1.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a != b)
+			v.AuxInt = boolToAuxInt(x != y)
 			return true
 		}
 		break
 	}
-	// match: (NeqPtr (Addr {a} _) (OffPtr [o] (Addr {b} _)))
-	// result: (ConstBool [a != b || o != 0])
+	// match: (NeqPtr (Addr {x} _) (OffPtr [o] (Addr {y} _)))
+	// result: (ConstBool [x != y || o != 0])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpAddr {
 				continue
 			}
-			a := auxToSym(v_0.Aux)
+			x := auxToSym(v_0.Aux)
 			if v_1.Op != OpOffPtr {
 				continue
 			}
@@ -15744,15 +15744,15 @@ func rewriteValuegeneric_OpNeqPtr(v *Value) bool {
 			if v_1_0.Op != OpAddr {
 				continue
 			}
-			b := auxToSym(v_1_0.Aux)
+			y := auxToSym(v_1_0.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a != b || o != 0)
+			v.AuxInt = boolToAuxInt(x != y || o != 0)
 			return true
 		}
 		break
 	}
-	// match: (NeqPtr (OffPtr [o1] (Addr {a} _)) (OffPtr [o2] (Addr {b} _)))
-	// result: (ConstBool [a != b || o1 != o2])
+	// match: (NeqPtr (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _)))
+	// result: (ConstBool [x != y || o1 != o2])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpOffPtr {
@@ -15763,7 +15763,7 @@ func rewriteValuegeneric_OpNeqPtr(v *Value) bool {
 			if v_0_0.Op != OpAddr {
 				continue
 			}
-			a := auxToSym(v_0_0.Aux)
+			x := auxToSym(v_0_0.Aux)
 			if v_1.Op != OpOffPtr {
 				continue
 			}
@@ -15772,39 +15772,39 @@ func rewriteValuegeneric_OpNeqPtr(v *Value) bool {
 			if v_1_0.Op != OpAddr {
 				continue
 			}
-			b := auxToSym(v_1_0.Aux)
+			y := auxToSym(v_1_0.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a != b || o1 != o2)
+			v.AuxInt = boolToAuxInt(x != y || o1 != o2)
 			return true
 		}
 		break
 	}
-	// match: (NeqPtr (LocalAddr {a} _ _) (LocalAddr {b} _ _))
-	// result: (ConstBool [a != b])
+	// match: (NeqPtr (LocalAddr {x} _ _) (LocalAddr {y} _ _))
+	// result: (ConstBool [x != y])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpLocalAddr {
 				continue
 			}
-			a := auxToSym(v_0.Aux)
+			x := auxToSym(v_0.Aux)
 			if v_1.Op != OpLocalAddr {
 				continue
 			}
-			b := auxToSym(v_1.Aux)
+			y := auxToSym(v_1.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a != b)
+			v.AuxInt = boolToAuxInt(x != y)
 			return true
 		}
 		break
 	}
-	// match: (NeqPtr (LocalAddr {a} _ _) (OffPtr [o] (LocalAddr {b} _ _)))
-	// result: (ConstBool [a != b || o != 0])
+	// match: (NeqPtr (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _)))
+	// result: (ConstBool [x != y || o != 0])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpLocalAddr {
 				continue
 			}
-			a := auxToSym(v_0.Aux)
+			x := auxToSym(v_0.Aux)
 			if v_1.Op != OpOffPtr {
 				continue
 			}
@@ -15813,15 +15813,15 @@ func rewriteValuegeneric_OpNeqPtr(v *Value) bool {
 			if v_1_0.Op != OpLocalAddr {
 				continue
 			}
-			b := auxToSym(v_1_0.Aux)
+			y := auxToSym(v_1_0.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a != b || o != 0)
+			v.AuxInt = boolToAuxInt(x != y || o != 0)
 			return true
 		}
 		break
 	}
-	// match: (NeqPtr (OffPtr [o1] (LocalAddr {a} _ _)) (OffPtr [o2] (LocalAddr {b} _ _)))
-	// result: (ConstBool [a != b || o1 != o2])
+	// match: (NeqPtr (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _)))
+	// result: (ConstBool [x != y || o1 != o2])
 	for {
 		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
 			if v_0.Op != OpOffPtr {
@@ -15832,7 +15832,7 @@ func rewriteValuegeneric_OpNeqPtr(v *Value) bool {
 			if v_0_0.Op != OpLocalAddr {
 				continue
 			}
-			a := auxToSym(v_0_0.Aux)
+			x := auxToSym(v_0_0.Aux)
 			if v_1.Op != OpOffPtr {
 				continue
 			}
@@ -15841,9 +15841,9 @@ func rewriteValuegeneric_OpNeqPtr(v *Value) bool {
 			if v_1_0.Op != OpLocalAddr {
 				continue
 			}
-			b := auxToSym(v_1_0.Aux)
+			y := auxToSym(v_1_0.Aux)
 			v.reset(OpConstBool)
-			v.AuxInt = boolToAuxInt(a != b || o1 != o2)
+			v.AuxInt = boolToAuxInt(x != y || o1 != o2)
 			return true
 		}
 		break
@@ -16532,17 +16532,17 @@ func rewriteValuegeneric_OpNot(v *Value) bool {
 }
 func rewriteValuegeneric_OpOffPtr(v *Value) bool {
 	v_0 := v.Args[0]
-	// match: (OffPtr (OffPtr p [b]) [a])
-	// result: (OffPtr p [a+b])
+	// match: (OffPtr (OffPtr p [y]) [x])
+	// result: (OffPtr p [x+y])
 	for {
-		a := auxIntToInt64(v.AuxInt)
+		x := auxIntToInt64(v.AuxInt)
 		if v_0.Op != OpOffPtr {
 			break
 		}
-		b := auxIntToInt64(v_0.AuxInt)
+		y := auxIntToInt64(v_0.AuxInt)
 		p := v_0.Args[0]
 		v.reset(OpOffPtr)
-		v.AuxInt = int64ToAuxInt(a + b)
+		v.AuxInt = int64ToAuxInt(x + y)
 		v.AddArg(p)
 		return true
 	}
@@ -20678,34 +20678,34 @@ func rewriteValuegeneric_OpSelectN(v *Value) bool {
 	v_0 := v.Args[0]
 	b := v.Block
 	config := b.Func.Config
-	// match: (SelectN [0] (MakeResult a ___))
-	// result: a
+	// match: (SelectN [0] (MakeResult x ___))
+	// result: x
 	for {
 		if auxIntToInt64(v.AuxInt) != 0 || v_0.Op != OpMakeResult || len(v_0.Args) < 1 {
 			break
 		}
-		a := v_0.Args[0]
-		v.copyOf(a)
+		x := v_0.Args[0]
+		v.copyOf(x)
 		return true
 	}
-	// match: (SelectN [1] (MakeResult a b ___))
-	// result: b
+	// match: (SelectN [1] (MakeResult x y ___))
+	// result: y
 	for {
 		if auxIntToInt64(v.AuxInt) != 1 || v_0.Op != OpMakeResult || len(v_0.Args) < 2 {
 			break
 		}
-		b := v_0.Args[1]
-		v.copyOf(b)
+		y := v_0.Args[1]
+		v.copyOf(y)
 		return true
 	}
-	// match: (SelectN [2] (MakeResult a b c ___))
-	// result: c
+	// match: (SelectN [2] (MakeResult x y z ___))
+	// result: z
 	for {
 		if auxIntToInt64(v.AuxInt) != 2 || v_0.Op != OpMakeResult || len(v_0.Args) < 3 {
 			break
 		}
-		c := v_0.Args[2]
-		v.copyOf(c)
+		z := v_0.Args[2]
+		v.copyOf(z)
 		return true
 	}
 	// match: (SelectN [0] call:(StaticCall {sym} s1:(Store _ (Const64 [sz]) s2:(Store _ src s3:(Store {t} _ dst mem)))))