[flang-commits] [flang] [flang] Fix TRANSFER into derived type with tail padding zeroing pad bytes (PR #223814)

[via flang-commits]

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@@ -151,3 +151,24 @@ subroutine trans_test_alloc_source(store, src)
     real, allocatable :: src
     store = transfer(src, store)
   end subroutine
+
+  ! TRANSFER into a SEQUENCE derived type with tail padding: the assignment back
+  ! to the derived-type variable must use fir.copy (full storage size including
+  ! tail padding) rather than a field-by-field copy that silently drops padding.
+  subroutine trans_test_seq_tail_pad(raw, x)
+    ! CHECK-LABEL: func @_QPtrans_test_seq_tail_pad(
+    ! CHECK:         fir.call @_FortranATransfer(
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MattPD wrote:

This test passes with the parent's compiler. `-emit-hlfir` stops before `convert-hlfir-to-fir`, and the patch only changes `convert-hlfir-to-fir`, so the checked `fir.call @_FortranATransfer` and `hlfir.assign` lines are identical on the parent and on this branch. I ran the file's RUN line with the parent's compiler and FileCheck accepted the output. The subroutine's introductory comment mentions `fir.copy`, but `-emit-hlfir` output never contains it. A `bbc -emit-fir` RUN line checking for `fir.copy {{.*}} no_overlap` on the `sequence{a:i32,b:i8}` type fails on the parent and passes on this branch. `flang/test/Lower/OpenACC/acc-firstprivate-derived.f90` has a RUN line of this form.

https://github.com/llvm/llvm-project/pull/223814