reverting to old draft for testing

Author: badasahog

src/fsort.c

@@ -43,10 +43,13 @@ static void dradix_r(  // single-threaded recursive worker
     return;
   }
 
-  for (uint64_t i = 0, cumSum = 0; cumSum < n; ++i) { // cumSum<n better than i<width as may return early
-    if (!counts[i]) continue; // don't cumulate through 0s, important below to save a wasteful memset to zero
-    counts[i] = cumSum;
-    cumSum += counts[i];
+  uint64_t cumSum=0;
+  for (uint64_t i=0; cumSum<n; ++i) { // cumSum<n better than i<width as may return early
+    uint64_t tmp;
+    if ((tmp=counts[i])) {  // don't cumulate through 0s, important below to save a wasteful memset to zero
+      counts[i] = cumSum;
+      cumSum += tmp;
+    }
   } // leaves cumSum==n && 0<i && i<=width
 
   tmp=in;
@@ -68,9 +71,10 @@ static void dradix_r(  // single-threaded recursive worker
     return;
   }
 
-  for (uint64_t i = 0, cumSum = 0; cumSum < n; i++) {   // again, cumSum<n better than i<width as it can return early
+  cumSum=0;
+  for (int i=0; cumSum<n; ++i) {   // again, cumSum<n better than i<width as it can return early
     if (counts[i] == 0) continue;
-    const uint64_t thisN = counts[i] - cumSum;  // undo cummulate; i.e. diff
+    uint64_t thisN = counts[i] - cumSum;  // undo cummulate; i.e. diff
     if (thisN <= INSERT_THRESH) {
       dinsert(in+cumSum, thisN);  // for thisN==1 this'll return instantly. Probably better than several branches here.
     } else {