[gcc r12-1090] PR fortran/100656 - prevent ICE in gfc_conv_expr_present

[Harald Anlauf <anlauf@gcc.gnu.org>]

https://gcc.gnu.org/g:9d3a953ec4d2695e9a6bfa5f22655e2aea47a973

commit r12-1090-g9d3a953ec4d2695e9a6bfa5f22655e2aea47a973
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Thu May 27 13:55:11 2021 +0200

    PR fortran/100656 - prevent ICE in gfc_conv_expr_present
    
    gcc/fortran/ChangeLog:
    
            PR fortran/100656
            * trans-array.c (gfc_conv_ss_startstride): Do not call check for
            presence of a dummy argument when a symbol actually refers to a
            non-dummy.
    
    gcc/testsuite/ChangeLog:
    
            PR fortran/100656
            * gfortran.dg/bounds_check_22.f90: New test.

Diff:
---
 gcc/fortran/trans-array.c                     |  5 +++--
 gcc/testsuite/gfortran.dg/bounds_check_22.f90 | 12 ++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/gcc/fortran/trans-array.c b/gcc/fortran/trans-array.c
index 6d38ea78273..7eeef554c0f 100644
--- a/gcc/fortran/trans-array.c
+++ b/gcc/fortran/trans-array.c
@@ -4718,8 +4718,9 @@ done:
 
 	  /* For optional arguments, only check bounds if the argument is
 	     present.  */
-	  if (expr->symtree->n.sym->attr.optional
-	      || expr->symtree->n.sym->attr.not_always_present)
+	  if ((expr->symtree->n.sym->attr.optional
+	       || expr->symtree->n.sym->attr.not_always_present)
+	      && expr->symtree->n.sym->attr.dummy)
 	    tmp = build3_v (COND_EXPR,
 			    gfc_conv_expr_present (expr->symtree->n.sym),
 			    tmp, build_empty_stmt (input_location));
diff --git a/gcc/testsuite/gfortran.dg/bounds_check_22.f90 b/gcc/testsuite/gfortran.dg/bounds_check_22.f90
new file mode 100644
index 00000000000..a84e3dd4f51
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/bounds_check_22.f90
@@ -0,0 +1,12 @@
+! { dg-do compile }
+! { dg-options "-fcheck=bounds" }
+! PR fortran/100656 - ICE in gfc_conv_expr_present
+
+subroutine s(x)
+  character(:), allocatable, optional :: x(:)
+  if ( present(x) ) then
+     if ( allocated(x) ) then
+        x = 'a' // x // 'e'
+     end if
+  end if
+end