Revert "[flang][fir] Add fir.if -> scf.if and add filecheck test … (#142965)" (#145345)

This reverts commit 823750d.

Test causes segfault on aix flang builder.

Author: lei137

flang/lib/Optimizer/Transforms/FIRToSCF.cpp

@@ -87,48 +87,13 @@ struct DoLoopConversion : public OpRewritePattern<fir::DoLoopOp> {
     return success();
   }
 };
-
-struct IfConversion : public OpRewritePattern<fir::IfOp> {
-  using OpRewritePattern<fir::IfOp>::OpRewritePattern;
-  LogicalResult matchAndRewrite(fir::IfOp ifOp,
-                                PatternRewriter &rewriter) const override {
-    mlir::Location loc = ifOp.getLoc();
-    mlir::detail::TypedValue<mlir::IntegerType> condition = ifOp.getCondition();
-    ValueTypeRange<ResultRange> resultTypes = ifOp.getResultTypes();
-    mlir::scf::IfOp scfIfOp = rewriter.create<scf::IfOp>(
-        loc, resultTypes, condition, !ifOp.getElseRegion().empty());
-    // then region
-    scfIfOp.getThenRegion().takeBody(ifOp.getThenRegion());
-    Block &scfThenBlock = scfIfOp.getThenRegion().front();
-    Operation *scfThenTerminator = scfThenBlock.getTerminator();
-    // fir.result->scf.yield
-    rewriter.setInsertionPointToEnd(&scfThenBlock);
-    rewriter.replaceOpWithNewOp<scf::YieldOp>(scfThenTerminator,
-                                              scfThenTerminator->getOperands());
-
-    // else region
-    if (!ifOp.getElseRegion().empty()) {
-      scfIfOp.getElseRegion().takeBody(ifOp.getElseRegion());
-      mlir::Block &elseBlock = scfIfOp.getElseRegion().front();
-      mlir::Operation *elseTerminator = elseBlock.getTerminator();
-
-      rewriter.setInsertionPointToEnd(&elseBlock);
-      rewriter.replaceOpWithNewOp<scf::YieldOp>(elseTerminator,
-                                                elseTerminator->getOperands());
-    }
-
-    scfIfOp->setAttrs(ifOp->getAttrs());
-    rewriter.replaceOp(ifOp, scfIfOp);
-    return success();
-  }
-};
 } // namespace
 
 void FIRToSCFPass::runOnOperation() {
   RewritePatternSet patterns(&getContext());
-  patterns.add<DoLoopConversion, IfConversion>(patterns.getContext());
+  patterns.add<DoLoopConversion>(patterns.getContext());
   ConversionTarget target(getContext());
-  target.addIllegalOp<fir::DoLoopOp, fir::IfOp>();
+  target.addIllegalOp<fir::DoLoopOp>();
   target.markUnknownOpDynamicallyLegal([](Operation *) { return true; });
   if (failed(
           applyPartialConversion(getOperation(), target, std::move(patterns))))