[flang-commits] [flang] [flang][fir]: Add conversion of `fir.iterate_while` to `scf.while`. (PR #152439)

[Terapines MLIR via flang-commits]

================
@@ -88,6 +88,91 @@ struct DoLoopConversion : public OpRewritePattern<fir::DoLoopOp> {
   }
 };
 
+struct IterWhileConversion : public OpRewritePattern<fir::IterWhileOp> {
+  using OpRewritePattern<fir::IterWhileOp>::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(fir::IterWhileOp iterWhileOp,
+                                PatternRewriter &rewriter) const override {
+
+    Location loc = iterWhileOp.getLoc();
+    Value lowerBound = iterWhileOp.getLowerBound();
+    Value upperBound = iterWhileOp.getUpperBound();
+    Value step = iterWhileOp.getStep();
+
+    Value okInit = iterWhileOp.getIterateIn();
+    ValueRange iterArgs = iterWhileOp.getInitArgs();
+
+    SmallVector<Value> initVals;
+    initVals.push_back(lowerBound);
+    initVals.push_back(okInit);
+    initVals.append(iterArgs.begin(), iterArgs.end());
+
+    SmallVector<Type> loopTypes;
+    loopTypes.push_back(lowerBound.getType());
+    loopTypes.push_back(okInit.getType());
+    for (auto val : iterArgs)
+      loopTypes.push_back(val.getType());
+
+    auto scfWhileOp = scf::WhileOp::create(rewriter, loc, loopTypes, initVals);
+    rewriter.createBlock(&scfWhileOp.getBefore(), scfWhileOp.getBefore().end(),
+                         loopTypes,
+                         SmallVector<Location>(loopTypes.size(), loc));
+
+    rewriter.createBlock(&scfWhileOp.getAfter(), scfWhileOp.getAfter().end(),
+                         loopTypes,
+                         SmallVector<Location>(loopTypes.size(), loc));
+
+    {
+      rewriter.setInsertionPointToStart(&scfWhileOp.getBefore().front());
+      auto args = scfWhileOp.getBefore().getArguments();
+      auto iv = args[0];
+      auto ok = args[1];
+
+      Value inductionCmp = mlir::arith::CmpIOp::create(
+          rewriter, loc, mlir::arith::CmpIPredicate::sle, iv, upperBound);
+      Value cmp = mlir::arith::AndIOp::create(rewriter, loc, inductionCmp, ok);
+
+      mlir::scf::ConditionOp::create(rewriter, loc, cmp, args);
+    }
+
+    {
+      rewriter.setInsertionPointToStart(&scfWhileOp.getAfter().front());
+      auto args = scfWhileOp.getAfter().getArguments();
+      auto iv = args[0];
+
+      mlir::IRMapping mapping;
+      for (auto [oldArg, newVal] :
+           llvm::zip(iterWhileOp.getBody()->getArguments(), args))
+        mapping.map(oldArg, newVal);
+
+      for (auto &op : iterWhileOp.getBody()->without_terminator())
+        rewriter.clone(op, mapping);
----------------
terapines-osc-mlir wrote:

Thanks for the suggestion.  Code got refactored to use `rewriter.inlineBlockBefore`. :handshake: 

https://github.com/llvm/llvm-project/pull/152439