[flang-commits] [flang] [Flang]Add support for inlining hlfir.assign operation where both LHS and RHS are slices of the same array (PR #204532)

[Kaviya Rajendiran via flang-commits]

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@@ -130,6 +136,43 @@ class InlineHLFIRAssignConversion
     fir::FirOpBuilder builder(rewriter, assign.getOperation());
     builder.setInsertionPoint(assign);
 
+    const bool useWorkshare = flangomp::shouldUseWorkshareLowering(assign);
+    mlir::ArrayAttr accessGroups;
+    if (auto attrs = assign.getOperation()->getAttrOfType<mlir::ArrayAttr>(
+            fir::getAccessGroupsAttrName()))
+      accessGroups = attrs;
+
+    auto emitAssignFrom = [&](hlfir::Entity rhsEntity) {
+      hlfir::genNoAliasArrayAssignment(
+          loc, builder, rhsEntity, lhs, useWorkshare,
+          /*temporaryLHS=*/false, nullptr, accessGroups);
+    };
+
+    if (rhsNeedsTemporary) {
+      if (mlir::Value disjoint =
+              fir::ArraySectionAnalyzer::genRuntimeDisjointnessCheck(
+                  loc, builder, lhs, rhs)) {
+        builder.genIfThenElse(loc, disjoint)
+            .genThen([&]() { emitAssignFrom(rhs); })
+            .genElse([&]() {
+              mlir::Value tempExpr = hlfir::AsExprOp::create(builder, loc, rhs);
+              emitAssignFrom(hlfir::Entity{tempExpr});
+              hlfir::DestroyOp::create(builder, loc, tempExpr);
+            })
+            .end();
+        rewriter.eraseOp(assign);
+        return mlir::success();
+      }
+    }
+
+    // When rhsNeedsTemporary is true and genRuntimeDisjointnessCheck
+    // returned null, always use a temporary rhsExpr.
+    mlir::Value rhsTempExpr;
+    if (rhsNeedsTemporary) {
+      rhsTempExpr = hlfir::AsExprOp::create(builder, loc, rhs);
+      rhs = hlfir::Entity{rhsTempExpr};
+    }
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kaviya2510 wrote:

As you mentioned, this fallback check is not required for current implementation. So removed it.

https://github.com/llvm/llvm-project/pull/204532