Remove some unnecessary volatile qualifiers.

research/miniaudio_engine.h

@@ -3828,11 +3828,11 @@ MA_API ma_result ma_slot_allocator_alloc(ma_slot_allocator* pAllocator, ma_uint6
         for (iGroup = 0; iGroup < ma_countof(pAllocator->groups); iGroup += 1) {
             /* CAS */
             for (;;) {
-                volatile ma_uint32 oldBitfield; /* Making this volatile because we want to make sure the compiler does not optimize away the oldBitfield assignment. */
+                ma_uint32 oldBitfield;
                 ma_uint32 newBitfield;
                 ma_uint32 bitOffset;
 
-                oldBitfield = pAllocator->groups[iGroup].bitfield;  /* <-- This copy must happen. The compiler must not optimize this away. */
+                oldBitfield = pAllocator->groups[iGroup].bitfield;  /* <-- This copy must happen. The compiler must not optimize this away. pAllocator->groups[iGroup].bitfield is marked as volatile. */
 
                 /* Fast check to see if anything is available. */
                 if (oldBitfield == 0xFFFFFFFF) {
@@ -3896,10 +3896,10 @@ MA_API ma_result ma_slot_allocator_free(ma_slot_allocator* pAllocator, ma_uint64
 
     while (pAllocator->count > 0) {
         /* CAS */
-        volatile ma_uint32 oldBitfield; /* Making this volatile because we want to make sure the compiler does not optimize away the oldBitfield assignment. */
+        ma_uint32 oldBitfield;
         ma_uint32 newBitfield;
 
-        oldBitfield = pAllocator->groups[iGroup].bitfield;  /* <-- This copy must happen. The compiler must not optimize this away. */
+        oldBitfield = pAllocator->groups[iGroup].bitfield;  /* <-- This copy must happen. The compiler must not optimize this away. pAllocator->groups[iGroup].bitfield is marked as volatile. */
         newBitfield = oldBitfield & ~(1 << iBit);
 
         if (c89atomic_compare_and_swap_32(&pAllocator->groups[iGroup].bitfield, oldBitfield, newBitfield) == oldBitfield) {