[flang-commits] [flang] [flang] Reset all extents to zero for empty hlfir.elemental loops. (PR #124867)

[via flang-commits]

================
@@ -1759,3 +1759,38 @@ fir::factory::deduceOptimalExtents(mlir::ValueRange extents1,
   }
   return extents;
 }
+
+llvm::SmallVector<mlir::Value> fir::factory::updateRuntimeExtentsForEmptyArrays(
+    fir::FirOpBuilder &builder, mlir::Location loc, mlir::ValueRange extents) {
+  if (extents.size() <= 1)
+    return extents;
+
+  // Try to reduce the number of new zero constant operations.
+  // This just makes MLIR matching easier, if CSE is not run
+  // after this.
+  llvm::DenseMap<mlir::Type, mlir::Value> zeroesMap;
----------------
jeanPerier wrote:

Is it that common for extents values to have different types?

I am not against, but a single lazy zero mlir::Value for the extents (that will likely never be i1) would probably yield the same IR has the DenseMap in 99% of the cases.

https://github.com/llvm/llvm-project/pull/124867