diff --git a/src/cmd/compile/internal/ssa/cse.go b/src/cmd/compile/internal/ssa/cse.go
index 39861b6e2a..10f3b883b4 100644
--- a/src/cmd/compile/internal/ssa/cse.go
+++ b/src/cmd/compile/internal/ssa/cse.go
@@ -30,19 +30,21 @@ func cse(f *Func) {
 
 	// Make initial coarse partitions by using a subset of the conditions above.
 	a := make([]*Value, 0, f.NumValues())
-	auxIDs := auxmap{}
+	if f.auxmap == nil {
+		f.auxmap = auxmap{}
+	}
 	for _, b := range f.Blocks {
 		for _, v := range b.Values {
-			if auxIDs[v.Aux] == 0 {
-				auxIDs[v.Aux] = int32(len(auxIDs)) + 1
-			}
 			if v.Type.IsMemory() {
 				continue // memory values can never cse
 			}
+			if f.auxmap[v.Aux] == 0 {
+				f.auxmap[v.Aux] = int32(len(f.auxmap)) + 1
+			}
 			a = append(a, v)
 		}
 	}
-	partition := partitionValues(a, auxIDs)
+	partition := partitionValues(a, f.auxmap)
 
 	// map from value id back to eqclass id
 	valueEqClass := make([]ID, f.NumValues())
diff --git a/src/cmd/compile/internal/ssa/func.go b/src/cmd/compile/internal/ssa/func.go
index ea259190da..439e0b0394 100644
--- a/src/cmd/compile/internal/ssa/func.go
+++ b/src/cmd/compile/internal/ssa/func.go
@@ -43,6 +43,8 @@ type Func struct {
 	cachedSdom      SparseTree // cached dominator tree
 	cachedLoopnest  *loopnest  // cached loop nest information
 
+	auxmap auxmap // map from aux values to opaque ids used by CSE
+
 	constants map[int64][]*Value // constants cache, keyed by constant value; users must check value's Op and Type
 }