Revise row-by-row check

velox/exec/Window.cpp

@@ -285,9 +285,9 @@ void updateKRowsOffsetsColumn(
   int precedingFactor = isKPreceding ? -1 : 1;
   for (auto i = 0; i < numRows; i++) {
     auto startValue = (int64_t)(startRow + i) + precedingFactor * offsets[i];
-    // Considers integer overflow case.
-    if (startValue != (int32_t)startValue) {
-      // computeValidFrames will handle INT32_MAX to compute a valid index.
+    if (startValue > INT32_MAX || startValue < INT32_MIN) {
+      // Integer overflow. computeValidFrames will replace INT32_MAX set here
+      // with partition's final row index.
       rawFrameBounds[i] = startValue < 0 ? 0 : INT32_MAX;
     } else {
       rawFrameBounds[i] = startValue;
@@ -318,28 +318,25 @@ void Window::updateKRowsFrameBounds(
         (isKPreceding ? -constantOffset : constantOffset) + startRow;
 
     if (isKPreceding) {
-      // Considers a very large int64 constantOffset is used.
+      // Overflow.
       if (startValue < INT32_MIN) {
         std::fill_n(rawFrameBounds, numRows, 0);
         return;
       }
-      // Integer overflow cannot happen.
       std::iota(rawFrameBounds, rawFrameBounds + numRows, startValue);
       return;
     }
     // KFollowing.
     auto overflowStart = getOverflowStart(startValue);
     if (overflowStart >= 0 && overflowStart < numRows) {
       std::iota(rawFrameBounds, rawFrameBounds + overflowStart, startValue);
-      // For remaining, use INT32_MAX, which will be converted to valid index
-      // by computeValidFrames.
+      // For remaining rows that overflow happens, use INT32_MAX.
+      // computeValidFrames will replace it with partition's final row index.
       std::fill_n(
           rawFrameBounds + overflowStart, numRows - overflowStart, INT32_MAX);
       return;
     }
-    // Integer overflow cannot happen.
     std::iota(rawFrameBounds, rawFrameBounds + numRows, startValue);
-    return;
   } else {
     currentPartition_->extractColumn(
         frameArg.index, partitionOffset_, numRows, 0, frameArg.value);