diff --git a/scope.c b/scope.c
index 9e7bef5bff39..8c8a0d065471 100644
--- a/scope.c
+++ b/scope.c
@@ -246,8 +246,12 @@ Perl_tmps_grow_p(pTHX_ SSize_t ix)
 {
     SSize_t extend_to = ix;
 #ifndef STRESS_REALLOC
-    if (ix - PL_tmps_max < 128)
-        extend_to += (PL_tmps_max < 512) ? 128 : 512;
+    SSize_t grow_size = PL_tmps_max < 512 ? 128 : PL_tmps_max / 5;
+    if (extend_to >= SSize_t_MAX - grow_size)
+        /* trigger memwrap message or fail allocation */
+        extend_to = SSize_t_MAX-1;
+    else
+        extend_to += grow_size;
 #endif
     Renew(PL_tmps_stack, extend_to + 1, SV*);
     PL_tmps_max = extend_to + 1;
diff --git a/t/perf/tmps.t b/t/perf/tmps.t
index 956643b0f3d1..ad0a6be74e60 100644
--- a/t/perf/tmps.t
+++ b/t/perf/tmps.t
@@ -48,7 +48,6 @@ my $min_small = min($basetimes{$small_size}->@*);
 my $min_large = min($basetimes{$large_size}->@*);
 my $ratio = $large_size / $small_size;
 
-our $TODO = "tmps stack grows in O(n**2) time";
 my $worst = $min_small * $ratio * 2;
 note "worst allowed $worst";
 cmp_ok($min_large, '<', $worst,