diff --git a/src/OT/Var/VARC/VARC.cc b/src/OT/Var/VARC/VARC.cc
index 5b43f187f..6dade65f3 100644
--- a/src/OT/Var/VARC/VARC.cc
+++ b/src/OT/Var/VARC/VARC.cc
@@ -392,7 +392,7 @@ VARC::get_path_at (const hb_varc_context_t &c,
 
   hb_ubytes_t record = (this+glyphRecords)[idx];
 
-  float static_cache[sizeof (void *) * 16];
+  VarRegionList::cache_t static_cache[sizeof (void *) * 16];
   VarRegionList::cache_t *cache = parent_cache ?
 				  parent_cache :
 				  (this+varStore).create_cache (hb_array (static_cache));
diff --git a/src/hb-atomic.hh b/src/hb-atomic.hh
index de57cb475..403c8569a 100644
--- a/src/hb-atomic.hh
+++ b/src/hb-atomic.hh
@@ -50,7 +50,7 @@
 /* Defined externally, i.e. in config.h. */
 
 
-#elif !defined(HB_NO_MT) && defined(__ATOMIC_ACQUIRE)
+#elif !defined(HB_NO_MT) && defined(__ATOMIC_ACQUIRE) && 0
 
 /* C++11-style GCC primitives. We prefer these as they don't require linking to libstdc++ / libc++. */
 
diff --git a/src/hb-ot-layout-common.hh b/src/hb-ot-layout-common.hh
index 0026208f5..331897d60 100644
--- a/src/hb-ot-layout-common.hh
+++ b/src/hb-ot-layout-common.hh
@@ -2552,7 +2552,7 @@ struct SparseVarRegionAxis
 
 struct VarRegionList
 {
-  using cache_t = float;
+  using cache_t = hb_atomic_t<float>;
 
   float evaluate (unsigned int region_index,
 		  const int *coords, unsigned int coord_len,
@@ -2561,7 +2561,7 @@ struct VarRegionList
     if (unlikely (region_index >= regionCount))
       return 0.;
 
-    float *cached_value = nullptr;
+    cache_t *cached_value = nullptr;
     if (cache)
     {
       cached_value = &(cache[region_index]);
@@ -2730,7 +2730,7 @@ struct SparseVariationRegion : Array16Of<SparseVarRegionAxis>
 
 struct SparseVarRegionList
 {
-  using cache_t = float;
+  using cache_t = hb_atomic_t<float>;
 
   float evaluate (unsigned int region_index,
 		  const int *coords, unsigned int coord_len,
@@ -2739,7 +2739,7 @@ struct SparseVarRegionList
     if (unlikely (region_index >= regions.len))
       return 0.;
 
-    float *cached_value = nullptr;
+    hb_atomic_t<float> *cached_value = nullptr;
     if (cache)
     {
       cached_value = &(cache[region_index]);
@@ -3190,7 +3190,7 @@ struct ItemVariationStore
     unsigned count = (this+regions).regionCount;
     if (!count) return nullptr;
 
-    float *cache = (float *) hb_malloc (sizeof (float) * count);
+    cache_t *cache = (cache_t *) hb_malloc (sizeof (float) * count);
     if (unlikely (!cache)) return nullptr;
 
     for (unsigned i = 0; i < count; i++)
@@ -3440,7 +3440,7 @@ struct MultiItemVariationStore
 {
   using cache_t = SparseVarRegionList::cache_t;
 
-  cache_t *create_cache (hb_array_t<float> static_cache = hb_array_t<float> ()) const
+  cache_t *create_cache (hb_array_t<cache_t> static_cache = hb_array_t<cache_t> ()) const
   {
 #ifdef HB_NO_VAR
     return nullptr;
@@ -3448,12 +3448,12 @@ struct MultiItemVariationStore
     auto &r = this+regions;
     unsigned count = r.regions.len;
 
-    float *cache;
+    cache_t *cache;
     if (count <= static_cache.length)
       cache = static_cache.arrayZ;
     else
     {
-      cache = (float *) hb_malloc (sizeof (float) * count);
+      cache = (cache_t *) hb_malloc (sizeof (float) * count);
       if (unlikely (!cache)) return nullptr;
     }
 
@@ -3464,7 +3464,7 @@ struct MultiItemVariationStore
   }
 
   static void destroy_cache (cache_t *cache,
-			     hb_array_t<float> static_cache = hb_array_t<float> ())
+			     hb_array_t<cache_t> static_cache = hb_array_t<cache_t> ())
   {
     if (cache != static_cache.arrayZ)
       hb_free (cache);
diff --git a/src/hb-subset-plan.cc b/src/hb-subset-plan.cc
index c88fd75a5..f3230ba2a 100644
--- a/src/hb-subset-plan.cc
+++ b/src/hb-subset-plan.cc
@@ -408,7 +408,7 @@ _remap_variation_indices (const OT::ItemVariationStore &var_store,
 {
   if (&var_store == &Null (OT::ItemVariationStore)) return;
   unsigned subtable_count = var_store.get_sub_table_count ();
-  float *store_cache = var_store.create_cache ();
+  auto *store_cache = var_store.create_cache ();
 
   unsigned new_major = 0, new_minor = 0;
   unsigned last_major = (variation_indices.get_min ()) >> 16;
@@ -1161,12 +1161,12 @@ _update_instance_metrics_map_from_cff2 (hb_subset_plan_t *plan)
 
   hb_glyph_extents_t extents = {0x7FFF, -0x7FFF};
   OT::hmtx_accelerator_t _hmtx (plan->source);
-  float *hvar_store_cache = nullptr;
+  OT::ItemVariationStore::cache_t *hvar_store_cache = nullptr;
   if (_hmtx.has_data () && _hmtx.var_table.get_length ())
     hvar_store_cache = _hmtx.var_table->get_var_store ().create_cache ();
 
   OT::vmtx_accelerator_t _vmtx (plan->source);
-  float *vvar_store_cache = nullptr;
+  OT::ItemVariationStore::cache_t *vvar_store_cache = nullptr;
   if (_vmtx.has_data () && _vmtx.var_table.get_length ())
     vvar_store_cache = _vmtx.var_table->get_var_store ().create_cache ();