Commit f0997107 authored by Nguyen, Thien Minh's avatar Nguyen, Thien Minh
Browse files

Using SCF While loop 



All the loop constructs have now been converted to Affine/SCF

Signed-off-by: default avatarThien Nguyen <nguyentm@ornl.gov>
parent 7ae612a7

mlir/parsers/qasm3/tests/test_loop_stmts.cpp

+2 −0
Original line number Diff line number Diff line
@@ -64,6 +64,8 @@ QCOR_EXPECT_TRUE(i == 10); 
  auto mlir2 = qcor::mlir_compile(while_stmt, "while_stmt",

                                 qcor::OutputType::MLIR, false);

  std::cout << mlir2 << "\n";

  // We're using SCF while loop:

  EXPECT_TRUE(mlir2.find("scf.while") != std::string::npos);

  EXPECT_FALSE(qcor::execute(while_stmt, "while_stmt"));



    const std::string decrement = R"#(OPENQASM 3;

mlir/parsers/qasm3/visitor_handlers/loop_stmt_handler.cpp

+27 −43
Original line number Diff line number Diff line
@@ -408,52 +408,36 @@ void qasm3_visitor::createWhileLoop( 
  auto loop_signature = context->loopSignature();

  auto program_block = context->programBlock();

  assert(loop_signature->booleanExpression());

  auto main_block = builder.saveInsertionPoint();

  auto cachedBuilder = builder;

  mlir::scf::WhileOp whileOp = builder.create<mlir::scf::WhileOp>(

      location, mlir::TypeRange() /*resultTypes*/,

      mlir::ValueRange() /*operands*/);



  // FIXME: convert to mlir::scf::WhileOp (should be easy since it's

  // conditioned on an i1 value)

  // this is a while loop

  auto while_expr = loop_signature->booleanExpression();



  // Create a new scope for the for loop

  symbol_table.enter_new_scope();



  auto currRegion = builder.getBlock()->getParent();



  auto savept = builder.saveInsertionPoint();

  auto headerBlock = builder.createBlock(currRegion, currRegion->end());

  auto bodyBlock = builder.createBlock(currRegion, currRegion->end());

  auto exitBlock = builder.createBlock(currRegion, currRegion->end());



  builder.restoreInsertionPoint(savept);

  builder.create<mlir::BranchOp>(location, headerBlock);

  mlir::Block *before = builder.createBlock(&whileOp.before(), {}, {});

  mlir::Block *after = builder.createBlock(&whileOp.after(), {}, {});



  builder.setInsertionPointToEnd(headerBlock);

  // Build the "before" region:

  // In a "while" loop, this region computes the condition. 

  builder.setInsertionPointToStart(&whileOp.before().front());

  qasm3_expression_generator exp_generator(builder, symbol_table, file_name);

  exp_generator.visit(while_expr);

  auto expr_value = exp_generator.current_value;

  builder.create<mlir::CondBranchOp>(location, expr_value, bodyBlock,

                                     exitBlock);



  builder.setInsertionPointToStart(bodyBlock);

  current_loop_exit_block = exitBlock;

  current_loop_header_block = headerBlock;



  exp_generator.visit(loop_signature->booleanExpression());

  mlir::Value cond = exp_generator.current_value;

  builder.create<mlir::scf::ConditionOp>(location, cond, before->getArguments());

  builder.setInsertionPointToStart(&whileOp.after().front());



  // Build the "after" region:

  // In a "while" loop, this region is the loop body.

  builder.setInsertionPointToStart(&whileOp.after().front());

  {

    symbol_table.enter_new_scope();

    visitChildren(program_block);



  current_loop_header_block = nullptr;

  current_loop_exit_block = nullptr;



  builder.create<mlir::BranchOp>(location, headerBlock);

  builder.setInsertionPointToStart(exitBlock);



    symbol_table.exit_scope();



  // This is where we do some manipulation of

  // the basic blocks, lets store the current last block

  // so that finalize_mlirgen() can add return and deallocs

  // correctly



  symbol_table.set_last_created_block(exitBlock);

    // 'After' block must end with a yield op.

    builder.create<mlir::scf::YieldOp>(location);

  }



  builder = cachedBuilder;

  builder.restoreInsertionPoint(main_block);

}

} // namespace qcor
 
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