Merge pull request #5934 from awallace-cray/chapdev-204

Fix rank changes with mixed stride (cherry-pick #5929)
[approved for release/1.15]

Author: awallace-cray

Diff for: modules/internal/ChapelArray.chpl

@@ -1112,14 +1112,22 @@ module ChapelArray {
       // Compute which dimensions are collapsed and what the index
       // (idx) is in the event that it is.  These will be stored in
       // the array view to convert from lower-D indices to higher-D.
+      // Also compute the upward-facing rank and tuple of ranges.
       //
       var collapsedDim: rank*bool;
       var idx: rank*idxType;
+      param uprank = chpl__countRanges((...args));
+      param upstridable = this.stridable || chpl__anyRankChangeStridable(args);
+      var upranges: uprank*range(idxType=_value.idxType,
+                                 stridable=upstridable);
+      var updim = 1;
 
       for param i in 1..rank {
         if (isRange(args(i))) {
           collapsedDim(i) = false;
           idx(i) = dim(i).alignedLow;
+          upranges(updim) = this._value.dsiDim(i)[args(i)]; // intersect ranges
+          updim += 1;
         } else {
           collapsedDim(i) = true;
           idx(i) = args(i);
@@ -1128,9 +1136,7 @@ module ChapelArray {
 
       // Create distribution, domain, and array objects representing
       // the array view
-      var upranges = _getRankChangeRanges(args, this._value);
       const emptyrange: upranges(1).type;
-      param uprank = upranges.size;
       //
       // If idx isn't in the original domain, we need to generate an
       // empty upward facing domain (intersection is empty)
@@ -3100,13 +3106,33 @@ module ChapelArray {
 
 
   // computes || reduction over stridable of ranges
-  proc chpl__anyStridable(ranges, param d: int = 1) param {
+  proc chpl__anyStridable(ranges) param {
     for param i in 1..ranges.size do
       if ranges(i).stridable then
         return true;
     return false;
   }
 
+  // computes || reduction over stridable of ranges, but permits some
+  // elements not to be ranges (as in a rank-change slice)
+  proc chpl__anyRankChangeStridable(args) param {
+    for param i in 1..args.size do
+      if isRangeValue(args(i)) then
+        if args(i).stridable then
+          return true;
+    return false;
+  }
+
+  // the following pair of routines counts the number of ranges in its
+  // argument list and is used for rank-change slices
+  proc chpl__countRanges(arg) param {
+    return isRangeValue(arg):int;
+  }
+
+  proc chpl__countRanges(arg, args...) param {
+    return chpl__countRanges(arg) + chpl__countRanges((...args));
+  }
+
   // given a tuple args, returns true if the tuple contains only
   // integers and ranges; that is, it is a valid argument list for rank
   // change
@@ -3147,38 +3173,6 @@ module ChapelArray {
     //return help(1);
   }
 
-  proc _getRankChangeRanges(args, downdom) {
-    return collectRanges(1);
-
-    proc collectRanges(param dim: int) {
-      if isRange(args(dim)) {
-        const newRange = downdom.dsiDim(dim)[args(dim)]; // intersect ranges
-        return collectRanges(dim+1, (newRange,));
-      } else
-        return collectRanges(dim+1);
-    }
-
-    proc collectRanges(param dim: int, x: _tuple) {
-      if dim > args.size {
-        return x;
-      } else if dim < args.size {
-        if isRange(args(dim)) {
-          const newRange = downdom.dsiDim(dim)[args(dim)]; // intersect ranges
-          return collectRanges(dim+1, ((...x), newRange));
-        } else {
-          return collectRanges(dim+1, x);
-        }
-      } else {
-        if isRange(args(dim)) {
-          const newRange = downdom.dsiDim(dim)[args(dim)]; // intersect ranges
-          return ((...x), newRange);
-        } else {
-          return x;
-        }
-      }
-    }
-  }
-
   //
   // Assignment of domains and arrays
   //

Diff for: test/arrays/rankChange/rankChangeMixStridables.chpl

@@ -0,0 +1,8 @@
+config const n = 5;
+config const it = 3;
+
+var b: [0..n+1, 0..n+1, 0..1] bool;
+
+b[2..n-1 by 2, 2..n-1, 0] = true;
+
+writeln(b);

Diff for: test/arrays/rankChange/rankChangeMixStridables.good

@@ -0,0 +1,55 @@
+false false
+false false
+false false
+false false
+false false
+false false
+false false
+
+false false
+false false
+false false
+false false
+false false
+false false
+false false
+
+false false
+false false
+true false
+true false
+true false
+false false
+false false
+
+false false
+false false
+false false
+false false
+false false
+false false
+false false
+
+false false
+false false
+true false
+true false
+true false
+false false
+false false
+
+false false
+false false
+false false
+false false
+false false
+false false
+false false
+
+false false
+false false
+false false
+false false
+false false
+false false
+false false