[PATCH] D119373: [flang] Make folding of LEN less aggressive

[Eric Schweitz via Phabricator via llvm-commits]

schweitz updated this revision to Diff 407332.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119373/new/

https://reviews.llvm.org/D119373

Files:
  flang/lib/Evaluate/fold-integer.cpp
  flang/test/Evaluate/rewrite01.f90


Index: flang/test/Evaluate/rewrite01.f90
===================================================================
--- flang/test/Evaluate/rewrite01.f90
+++ flang/test/Evaluate/rewrite01.f90
@@ -76,4 +76,43 @@
   !CHECK: PRINT *, 1_4
   print *, lbound(returns_array_3(), dim=1)
 end subroutine
+
+subroutine len_test(a,b, c, d, e, n, m)
+  character(*), intent(in) :: a
+  character(*) :: b
+  external b
+  character(10), intent(in) :: c
+  character(10) :: d
+  external d
+  integer, intent(in) :: n, m
+  character(n), intent(in) :: e
+
+  !CHECK: PRINT *, len(a)
+  print *, len(a)
+  !CHECK: PRINT *, 5_4
+  print *, len(a(1:5))
+  !CHECK: PRINT *, len(b(a))
+  print *, len(b(a))
+  !CHECK: PRINT *, len(b(a)//a)
+  print *, len(b(a) // a)
+  !CHECK: PRINT *, 10_4
+  print *, len(c)
+  !CHECK: PRINT *, len(c(int(i,kind=8):int(j,kind=8)))
+  print *, len(c(i:j))
+  !CHECK: PRINT *, 5_4
+  print *, len(c(1:5))
+  !CHECK: PRINT *, 10_4
+  print *, len(d(c))
+  !CHECK: PRINT *, 20_4
+  print *, len(d(c) // c)
+  !CHECK: PRINT *, 0_4
+  print *, len(a(10:4))
+  !CHECK: PRINT *, len(a(int(n,kind=8):int(m,kind=8)))
+  print *, len(a(n:m))
+  !CHECK: PRINT *, len(b(a(int(n,kind=8):int(m,kind=8))))
+  print *, len(b(a(n:m)))
+  !CHECK: PRINT *, len(e(4_8:max(0_8,int(n,kind=8))))
+  print *, len(e(4:))
+end subroutine len_test
+
 end module
Index: flang/lib/Evaluate/fold-integer.cpp
===================================================================
--- flang/lib/Evaluate/fold-integer.cpp
+++ flang/lib/Evaluate/fold-integer.cpp
@@ -677,7 +677,11 @@
       return std::visit(
           [&](auto &kx) {
             if (auto len{kx.LEN()}) {
-              return Fold(context, ConvertToType<T>(*std::move(len)));
+              if (IsScopeInvariantExpr(*len)) {
+                return Fold(context, ConvertToType<T>(*std::move(len)));
+              } else {
+                return Expr<T>{std::move(funcRef)};
+              }
             } else {
               return Expr<T>{std::move(funcRef)};
             }


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