diff --git a/src/cmd/compile/internal/gc/util.go b/src/cmd/compile/internal/gc/util.go
index bb5cede5a6..c62bd00808 100644
--- a/src/cmd/compile/internal/gc/util.go
+++ b/src/cmd/compile/internal/gc/util.go
@@ -57,8 +57,13 @@ func startProfile() {
 			Fatalf("%v", err)
 		}
 		atExit(func() {
-			runtime.GC() // profile all outstanding allocations
-			if err := pprof.WriteHeapProfile(f); err != nil {
+			// Profile all outstanding allocations.
+			runtime.GC()
+			// compilebench parses the memory profile to extract memstats,
+			// which are only written in the legacy pprof format.
+			// See golang.org/issue/18641 and runtime/pprof/pprof.go:writeHeap.
+			const writeLegacyFormat = 1
+			if err := pprof.Lookup("heap").WriteTo(f, writeLegacyFormat); err != nil {
 				Fatalf("%v", err)
 			}
 		})