Revert "[flang][lowering] Fix lowering of nested WHERE statements" (#1081)

This reverts commit b80bc91.

Author: clementval

flang/lib/Lower/ConvertExpr.cpp

@@ -3821,36 +3821,34 @@ class ArrayExprLowering {
 
       // Handle the negated conditions. See 10.2.3.2p4 as to why this control
       // structure is produced.
-      auto masks = implicitSpace->getMasks();
-      for (auto maskExprs : masks) {
-        const auto size = maskExprs.size() - 1;
-        for (std::remove_const_t<decltype(size)> i = 0; i < size; ++i)
-          if (maskExprs[i]) {
-            auto ifOp = builder.create<fir::IfOp>(
-                loc, mlir::TypeRange{innerArg.getType()},
-                fir::getBase(genCond(
-                    implicitSpace->getBindingWithShape(maskExprs[i]), iters)),
-                /*withElseRegion=*/true);
-            builder.create<fir::ResultOp>(loc, ifOp.getResult(0));
-            builder.setInsertionPointToStart(&ifOp.thenRegion().front());
-            builder.create<fir::ResultOp>(loc, innerArg);
-            builder.setInsertionPointToStart(&ifOp.elseRegion().front());
-          }
-
-        // The last condition is either non-negated or unconditionally negated.
-        if (maskExprs[size]) {
+      auto maskExprs = implicitSpace->getExprs();
+      const auto size = maskExprs.size() - 1;
+      for (std::remove_const_t<decltype(size)> i = 0; i < size; ++i)
+        if (maskExprs[i]) {
           auto ifOp = builder.create<fir::IfOp>(
               loc, mlir::TypeRange{innerArg.getType()},
               fir::getBase(genCond(
-                  implicitSpace->getBindingWithShape(maskExprs[size]), iters)),
+                  implicitSpace->getBindingWithShape(maskExprs[i]), iters)),
               /*withElseRegion=*/true);
           builder.create<fir::ResultOp>(loc, ifOp.getResult(0));
-          builder.setInsertionPointToStart(&ifOp.elseRegion().front());
-          builder.create<fir::ResultOp>(loc, innerArg);
           builder.setInsertionPointToStart(&ifOp.thenRegion().front());
-        } else {
-          // do nothing
+          builder.create<fir::ResultOp>(loc, innerArg);
+          builder.setInsertionPointToStart(&ifOp.elseRegion().front());
         }
+
+      // The last condition is either non-negated or unconditionally negated.
+      if (maskExprs[size]) {
+        auto ifOp = builder.create<fir::IfOp>(
+            loc, mlir::TypeRange{innerArg.getType()},
+            fir::getBase(genCond(
+                implicitSpace->getBindingWithShape(maskExprs[size]), iters)),
+            /*withElseRegion=*/true);
+        builder.create<fir::ResultOp>(loc, ifOp.getResult(0));
+        builder.setInsertionPointToStart(&ifOp.elseRegion().front());
+        builder.create<fir::ResultOp>(loc, innerArg);
+        builder.setInsertionPointToStart(&ifOp.thenRegion().front());
+      } else {
+        // do nothing
       }
     }
 

flang/lib/Lower/IterationSpace.h

@@ -150,6 +150,7 @@ class ImplicitIterSpace
     return maskVarMap.lookup(exp).second;
   }
 
+private:
   // Stack of WHERE constructs, each building a list of mask expressions.
   llvm::SmallVector<llvm::SmallVector<FrontEndMaskExpr>> &getMasks() {
     return stack;
@@ -159,7 +160,6 @@ class ImplicitIterSpace
     return stack;
   }
 
-private:
   llvm::DenseMap<FrontEndExpr, std::pair<mlir::Value, mlir::Value>> maskVarMap;
 };