diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index 79017d2721..2fa7ef84f5 100644
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -192,7 +192,7 @@ func Main(archInit func(*Arch)) {
 	flag.BoolVar(&pure_go, "complete", false, "compiling complete package (no C or assembly)")
 	flag.StringVar(&debugstr, "d", "", "print debug information about items in `list`; try -d help")
 	flag.BoolVar(&flagDWARF, "dwarf", true, "generate DWARF symbols")
-	flag.BoolVar(&Ctxt.Flag_locationlists, "dwarflocationlists", false, "add location lists to DWARF in optimized mode")
+	flag.BoolVar(&Ctxt.Flag_locationlists, "dwarflocationlists", true, "add location lists to DWARF in optimized mode")
 	flag.IntVar(&genDwarfInline, "gendwarfinl", 2, "generate DWARF inline info records")
 	objabi.Flagcount("e", "no limit on number of errors reported", &Debug['e'])
 	objabi.Flagcount("f", "debug stack frames", &Debug['f'])
diff --git a/src/cmd/compile/internal/ssa/debug_test.go b/src/cmd/compile/internal/ssa/debug_test.go
index 48dbaea27f..b066816dc9 100644
--- a/src/cmd/compile/internal/ssa/debug_test.go
+++ b/src/cmd/compile/internal/ssa/debug_test.go
@@ -135,10 +135,10 @@ func TestNexting(t *testing.T) {
 		t.Skip(skipReasons[:len(skipReasons)-2])
 	}
 
-	optFlags := "-dwarflocationlists"
+	optFlags := "" // Whatever flags are needed to test debugging of optimized code.
 	if !*useDelve && !*inlines {
 		// For gdb (default), disable inlining so that a compiler test does not depend on library code.
-		// TODO: This may not be necessary with 1.10 and later.
+		// TODO: Technically not necessary in 1.10, but it causes a largish regression that needs investigation.
 		optFlags += " -l"
 	}
 
diff --git a/src/runtime/runtime-gdb_test.go b/src/runtime/runtime-gdb_test.go
index c96bb95222..090e1c61d0 100644
--- a/src/runtime/runtime-gdb_test.go
+++ b/src/runtime/runtime-gdb_test.go
@@ -234,11 +234,16 @@ func testGdbPython(t *testing.T, cgo bool) {
 		t.Fatalf("print strvar failed: %s", bl)
 	}
 
-	// Issue 16338: ssa decompose phase can split a structure into
-	// a collection of scalar vars holding the fields. In such cases
+	// The exact format of composite values has changed over time.
+	// For issue 16338: ssa decompose phase split a slice into
+	// a collection of scalar vars holding its fields. In such cases
 	// the DWARF variable location expression should be of the
 	// form "var.field" and not just "field".
-	infoLocalsRe := regexp.MustCompile(`.*\sslicevar.cap = `)
+	// However, the newer dwarf location list code reconstituted
+	// aggregates from their fields and reverted their printing
+	// back to its original form.
+
+	infoLocalsRe := regexp.MustCompile(`slicevar *= *\[\]string *= *{"def"}`)
 	if bl := blocks["info locals"]; !infoLocalsRe.MatchString(bl) {
 		t.Fatalf("info locals failed: %s", bl)
 	}