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[flang] Lower alternate return 

This patch adds the lowering infrastructure for the lowering of
alternat returns.

This patch is part of the upstreaming effort from fir-dev branch.

Depends on D121698

Reviewed By: PeteSteinfeld

Differential Revision: https://reviews.llvm.org/D121699

Co-authored-by: V Donaldson <vdonaldson@nvidia.com>
Co-authored-by: Jean Perier <jperier@nvidia.com>
Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
This commit is contained in:
Valentin Clement 2022-03-15 22:03:14 +01:00
parent 76134f4138
commit 8b50353335
No known key found for this signature in database
GPG Key ID: 086D54783C928776
2 changed files with 64 additions and 1 deletions
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16
flang/lib/Lower/Bridge.cpp
View File

@ -2008,7 +2008,21 @@ private:
}
mlir::Location loc = toLocation();
if (stmt.v) {
TODO(loc, "Alternate return statement");
// Alternate return statement - If this is a subroutine where some
// alternate entries have alternate returns, but the active entry point
// does not, ignore the alternate return value. Otherwise, assign it
// to the compiler-generated result variable.
const Fortran::semantics::Symbol &symbol = funit->getSubprogramSymbol();
if (Fortran::semantics::HasAlternateReturns(symbol)) {
Fortran::lower::StatementContext stmtCtx;
const Fortran::lower::SomeExpr *expr =
Fortran::semantics::GetExpr(*stmt.v);
assert(expr && "missing alternate return expression");
mlir::Value altReturnIndex = builder->createConvert(
loc, builder->getIndexType(), createFIRExpr(loc, expr, stmtCtx));
builder->create<fir::StoreOp>(loc, altReturnIndex,
getAltReturnResult(symbol));
}
}
// Branch to the last block of the SUBROUTINE, which has the actual return.
if (!funit->finalBlock) {

49
flang/test/Lower/alternate-return.f90 Normal file
View File

@ -0,0 +1,49 @@
! RUN: bbc -emit-fir -o - %s | FileCheck %s
! CHECK-LABEL: func @_QPss
subroutine ss(n)
print*, n
! CHECK: return{{$}}
return
! CHECK-LABEL: func @_QPee
entry ee(n,*)
print*, n
! CHECK: return %{{.}} : index
return 1
end
! CHECK-LABEL: func @_QQmain
call ss(7)
call ee(2, *3)
print*, 'default'
3 print*, 3
print*, k(10,20)
print*, k(15,15)
print*, k(20,10)
end
! CHECK-LABEL: func @_QPk
function k(n1, n2)
! CHECK-NOT: ^bb
! CHECK: [[selector:%[0-9]+]] = fir.call @_QPs
! CHECK-NEXT: fir.select [[selector]] : index [1, ^[[block1:bb[0-9]+]], 2, ^[[block2:bb[0-9]+]], unit, ^[[blockunit:bb[0-9]+]]
call s(n1, *5, n2, *7)
! CHECK: ^[[blockunit]]: // pred: ^bb0
k = 0; return;
! CHECK: ^[[block1]]: // pred: ^bb0
5 k = -1; return;
! CHECK: ^[[block2]]: // pred: ^bb0
7 k = 1; return
end
! CHECK-LABEL: func @_QPs
subroutine s(n1, *, n2, *)
! CHECK: [[retval:%[0-9]+]] = fir.alloca index {{{.*}}bindc_name = "s"}
! CHECK-COUNT-3: fir.store {{.*}} to [[retval]] : !fir.ref<index>
if (n1 < n2) return 1
if (n1 > n2) return 2
! CHECK: {{.*}} = fir.load [[retval]] : !fir.ref<index>
! CHECK-NEXT: return {{.*}} : index
return
end