[flang][openacc] Fix getBoundsString for reduction recipe name (#68146)

`getBoundsString` is used to generate the reduction recipe names when an
array section is provided. The lowerbound and upperbound were swapped.
This patch fixes it.

Author: clementval

flang/lib/Lower/OpenACC.cpp

@@ -492,8 +492,8 @@ std::string getBoundsString(llvm::SmallVector<mlir::Value> &bounds) {
             fir::getIntIfConstant(boundsOp.getLowerbound()) &&
             boundsOp.getUpperbound() &&
             fir::getIntIfConstant(boundsOp.getUpperbound())) {
-          boundStr << "lb" << *fir::getIntIfConstant(boundsOp.getUpperbound())
-                   << ".ub" << *fir::getIntIfConstant(boundsOp.getLowerbound());
+          boundStr << "lb" << *fir::getIntIfConstant(boundsOp.getLowerbound())
+                   << ".ub" << *fir::getIntIfConstant(boundsOp.getUpperbound());
         } else if (boundsOp.getExtent() &&
                    fir::getIntIfConstant(boundsOp.getExtent())) {
           boundStr << "ext" << *fir::getIntIfConstant(boundsOp.getExtent());

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

@@ -1059,7 +1059,7 @@ subroutine acc_reduction_add_static_slice(a)
 ! CHECK: %[[BOUND:.*]] = acc.bounds lowerbound(%[[LB]] : index) upperbound(%[[UB]] : index) stride(%[[C1]] : index) startIdx(%[[C1]] : index)
 ! FIR:   %[[RED:.*]] = acc.reduction varPtr(%[[ARG0]] : !fir.ref<!fir.array<100xi32>>) bounds(%[[BOUND]]) -> !fir.ref<!fir.array<100xi32>> {name = "a(11:20)"}
 ! HLFIR: %[[RED:.*]] = acc.reduction varPtr(%[[DECLARG0]]#1 : !fir.ref<!fir.array<100xi32>>) bounds(%[[BOUND]]) -> !fir.ref<!fir.array<100xi32>> {name = "a(11:20)"}
-! CHECK: acc.parallel reduction(@reduction_add_section_lb19.ub10_ref_100xi32 -> %[[RED]] : !fir.ref<!fir.array<100xi32>>)
+! CHECK: acc.parallel reduction(@reduction_add_section_lb10.ub19_ref_100xi32 -> %[[RED]] : !fir.ref<!fir.array<100xi32>>)
 
 subroutine acc_reduction_add_dynamic_extent_add(a)
   integer :: a(:)