[gcc r12-6336] Fortran: Fix handling of optional argument to SIZE intrinsic [PR103898]

[gcc r12-6336] Fortran: Fix handling of optional argument to SIZE intrinsic [PR103898]

[Sandra Loosemore]

https://gcc.gnu.org/g:55385f12f604fe242030f0a8fb057598c0f187a6

commit r12-6336-g55385f12f604fe242030f0a8fb057598c0f187a6
Author: Sandra Loosemore <sandra@codesourcery.com>
Date:   Thu Jan 6 11:23:18 2022 -0800

    Fortran: Fix handling of optional argument to SIZE intrinsic [PR103898]
    
    This patch fixes a think-o in the code that triggered an ICE
    in the test case.
    
    2021-01-06  Sandra Loosemore  <sandra@codesourcery.com>
    
            PR fortran/103898
    
            gcc/fortran/
            * trans-intrinsic.c (gfc_conv_intrinsic_size): Make size_var
            actually be a variable and fix surrounding code.
    
            gcc/testsuite/
            * gfortran.dg/pr103898.f90: New test.

Diff:
---
 gcc/fortran/trans-intrinsic.c          |  6 +++++-
 gcc/testsuite/gfortran.dg/pr103898.f90 | 15 +++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/gcc/fortran/trans-intrinsic.c b/gcc/fortran/trans-intrinsic.c
index 41252c9ae2c..aae34b06948 100644
--- a/gcc/fortran/trans-intrinsic.c
+++ b/gcc/fortran/trans-intrinsic.c
@@ -8006,10 +8006,14 @@ gfc_conv_intrinsic_size (gfc_se * se, gfc_expr * expr)
 	  cond = gfc_evaluate_now (cond, &se->pre);
 	  /* 'block2' contains the arg2 absent case, 'block' the arg2 present
 	      case; size_var can be used in both blocks. */
-	  tree size_var = gfc_tree_array_size (&block2, arg1, e, NULL_TREE);
+	  tree size_var = gfc_create_var (TREE_TYPE (size), "size");
 	  tmp = fold_build2_loc (input_location, MODIFY_EXPR,
 				 TREE_TYPE (size_var), size_var, size);
 	  gfc_add_expr_to_block (&block, tmp);
+	  size = gfc_tree_array_size (&block2, arg1, e, NULL_TREE);
+	  tmp = fold_build2_loc (input_location, MODIFY_EXPR,
+				 TREE_TYPE (size_var), size_var, size);
+	  gfc_add_expr_to_block (&block2, tmp);
 	  tmp = build3_v (COND_EXPR, cond, gfc_finish_block (&block),
 			  gfc_finish_block (&block2));
 	  gfc_add_expr_to_block (&se->pre, tmp);
diff --git a/gcc/testsuite/gfortran.dg/pr103898.f90 b/gcc/testsuite/gfortran.dg/pr103898.f90
new file mode 100644
index 00000000000..6b4bb30e10a
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr103898.f90
@@ -0,0 +1,15 @@
+! { dg-do compile }
+
+! This test used to ICE during gimplification (PR103898).
+
+Module g
+contains
+  function mysize(array, dim)
+    integer :: mysize
+    integer, dimension(:), intent(in)   :: array
+    integer, optional,     intent(in)   :: dim
+    if (present(dim)) then
+       mysize = size(array, dim=dim)
+    endif
+  end function mysize
+end module