[flang][openacc] Lower loop with collapse clause

Author: clementval

flang/lib/Lower/Bridge.cpp

@@ -21,6 +21,7 @@
 #include "flang/Lower/FIRBuilder.h"
 #include "flang/Lower/IO.h"
 #include "flang/Lower/Mangler.h"
+#include "flang/Lower/OpenACC.h"
 #include "flang/Lower/OpenMP.h"
 #include "flang/Lower/PFTBuilder.h"
 #include "flang/Lower/Runtime.h"
@@ -1057,7 +1058,13 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     mlir::emitWarning(toLocation(), "ignoring all compiler directives");
   }
 
-  void genFIR(const Fortran::parser::OpenACCConstruct &) { TODO(); }
+  void genFIR(const Fortran::parser::OpenACCConstruct &acc) {
+    auto insertPt = builder->saveInsertionPoint();
+    genOpenACCConstruct(*this, getEval(), acc);
+    for (auto &e : getEval().getNestedEvaluations())
+      genFIR(e);
+    builder->restoreInsertionPoint(insertPt);
+  }
 
   void genFIR(const Fortran::parser::OpenMPConstruct &omp) {
     genOpenMPConstruct(*this, getEval(), omp);

flang/test/Lower/OpenACC/acc-loop.f90

@@ -0,0 +1,54 @@
+! This test checks lowering of OpenACC loop directive.
+
+! RUN: bbc -fopenacc -emit-fir %s -o - | FileCheck %s
+
+program acc_loop
+
+  integer :: i, j
+  integer, parameter :: n = 10
+  real, dimension(n) :: a, b
+  real, dimension(n, n) :: c, d
+
+
+  !$acc loop
+  DO i = 1, n
+    a(i) = b(i)
+  END DO
+
+!CHECK:      acc.loop {
+!CHECK:        fir.do_loop
+!CHECK:        acc.yield
+!CHECK-NEXT: }
+
+  !$acc loop collapse(2)
+  DO i = 1, n
+    DO j = 1, n
+      c(i, j) = d(i, j)
+    END DO
+  END DO
+
+!CHECK:      acc.loop {
+!CHECK:        fir.do_loop
+!CHECK:          fir.do_loop
+!CHECK:        acc.yield
+!CHECK-NEXT: } attributes {collapse = 2 : i64}
+
+  !$acc loop
+  DO i = 1, n
+    !$acc loop
+    DO j = 1, n
+      c(i, j) = d(i, j)
+    END DO
+  END DO
+
+!CHECK:      acc.loop {
+!CHECK:        fir.do_loop
+!CHECK:          acc.loop {
+!CHECK:            fir.do_loop
+!CHECK:            acc.yield
+!CHECK-NEXT:   }
+!CHECK:        acc.yield
+!CHECK-NEXT: }
+
+end program
+

flang/tools/bbc/bbc.cpp

@@ -116,6 +116,10 @@ static llvm::cl::opt<bool> enableOpenMP("fopenmp",
                                         llvm::cl::desc("enable openmp"),
                                         llvm::cl::init(false));
 
+static llvm::cl::opt<bool> enableOpenACC("fopenacc",
+                                         llvm::cl::desc("enable openacc"),
+                                         llvm::cl::init(false));
+
 static llvm::cl::opt<bool> dumpModuleOnFailure("dump-module-on-failure",
                                                llvm::cl::init(false));
 
@@ -153,6 +157,12 @@ static mlir::LogicalResult convertFortranSourceToMLIR(
     options.predefinitions.emplace_back("_OPENMP", "201511");
   }
 
+  // enable parsing of OpenACC
+  if (enableOpenACC) {
+    options.features.Enable(Fortran::common::LanguageFeature::OpenACC);
+    options.predefinitions.emplace_back("_OPENACC", "201911");
+  }
+
   // prep for prescan and parse
   options.searchDirectories = includeDirs;
   Fortran::parser::Parsing parsing{semanticsContext.allSources()};