[flang-commits] [flang] [flang][OpenACC] Generalize cross-region GOTO exit handling for all ACC region ops (PR #187613)

[via flang-commits]

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@@ -3677,6 +3693,40 @@ class FirConverter : public Fortran::lower::AbstractConverter {
       localSymbols.popScope();
     builder->restoreInsertionPoint(insertPt);
 
+    // Generate jump table for GOTO exits from the ACC region.
+    if (needsExitSelector) {
+      auto exitInfo = accRegionExitStack.pop_back_val();
+      if (!exitInfo.exits.empty()) {
+        mlir::Location loc = toLocation();
+        mlir::Value sel = fir::LoadOp::create(*builder, loc, exitInfo.selector);
+        mlir::Block *continueBlock =
+            builder->getBlock()->splitBlock(builder->getBlock()->end());
+        if (exitInfo.exits.size() == 1) {
+          mlir::Value id = builder->createIntegerConstant(
+              loc, builder->getI32Type(), exitInfo.exits[0].first);
+          mlir::Value cmp = mlir::arith::CmpIOp::create(
+              *builder, loc, mlir::arith::CmpIPredicate::eq, sel, id);
+          mlir::cf::CondBranchOp::create(
+              *builder, loc, cmp, exitInfo.exits[0].second, continueBlock);
+        } else {
+          // Multiple exit targets: chain of comparisons.
+          for (auto &[id, target] : exitInfo.exits) {
+            mlir::Value idVal =
+                builder->createIntegerConstant(loc, builder->getI32Type(), id);
+            mlir::Value cmp = mlir::arith::CmpIOp::create(
+                *builder, loc, mlir::arith::CmpIPredicate::eq, sel, idVal);
+            mlir::Block *nextCheck =
+                builder->getBlock()->splitBlock(builder->getBlock()->end());
+            mlir::cf::CondBranchOp::create(*builder, loc, cmp, target,
+                                           nextCheck);
+            builder->setInsertionPointToEnd(nextCheck);
+          }
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jeanPerier wrote:

I think just having this loop instead of also having the special case for the 1 exit case is equivalent and less code (nextCheck will just construct the continueBlock in that case).

https://github.com/llvm/llvm-project/pull/187613