Hi,

Please CC fortran@gcc for Fortran patches.

Fortraners: Please see my add-on suggestion/.diff for 'do_simply' below and
the original email at
https://gcc.gnu.org/pipermail/gcc-patches/2023-March/613019.html

On 01.03.23 08:09, HAO CHEN GUI via Gcc-patches wrote:
The patch escalates the failure when Hollerith constant to real conversion
fails in native_interpret_expr. It finally reports an "Unclassifiable
statement" error.
I think we should do better than this (cf. below).
   The patch of pr95450 added a verification for decoding/encoding checking
in native_interpret_expr. native_interpret_expr may fail on real type
conversion and returns a NULL tree then. But upper layer calls don't handle
the failure so that an ICE is reported when the verification fails.

   IBM long double is an example. It doesn't have a unique memory presentation
for some real values. So it may not pass the verification. The new test
case shows the problem.

Bootstrapped and tested on powerpc64-linux BE and LE with no regressions.
I think the patch OK except for two items:
ChangeLog
2023-03-01  Haochen Gui <guih...@linux.ibm.com>

gcc/
      PR target/103628
      * fortran/target-memory.cc (gfc_interpret_float): Return FAIL when
      native_interpret_expr gets a NULL tree.
      * fortran/arith.cc (gfc_hollerith2real): Return NULL when
      gfc_interpret_float fails.

gcc/testsuite/
      PR target/103628
      * gfortran.dg/pr103628.f90: New.
...
--- a/gcc/fortran/target-memory.cc
+++ b/gcc/fortran/target-memory.cc
@@ -417,10 +417,13 @@ gfc_interpret_float (int kind, unsigned char *buffer, 
size_t buffer_size,
  {
    gfc_set_model_kind (kind);
    mpfr_init (real);
-  gfc_conv_tree_to_mpfr (real,
-                      native_interpret_expr (gfc_get_real_type (kind),
-                                             buffer, buffer_size));

+  tree source  = native_interpret_expr (gfc_get_real_type (kind), buffer,
+                                     buffer_size);
+  if (!source)
+    return 0;
+
+  gfc_conv_tree_to_mpfr (real, source);
Can you move the mpfr_init before the 'gfc_conv...mfpr' to avoid
pointless allocation/leaks by mpfr_init.
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr103628.f90
@@ -0,0 +1,14 @@
+! { dg-do compile { target powerpc*-*-* } }
+! { dg-options "-O2 -mabi=ibmlongdouble" }
+
+! Test to ensure that it reports an "Unclassifiable statement" error
+! instead of throwing an ICE when the memory represent of the HOLLERITH
+! string is not unique with ibm long double encoding.
...
+  real(kind = k):: b = 4h1234
...
+! { dg-warning "Conversion from HOLLERITH" "warning" { target powerpc*-*-* } 
10 }
+! { dg-error "Unclassifiable statement" "error" { target powerpc*-*-* } 10 }

I find a generic error pointing to the beginning of the line not that helpful.
I did wonder about something specific, but at the end for a rather special case,
a generic catch-all for 'do_simplify' seems to make sense. The callers of 
'do_simplify'
clearly assume that this function will always (indirectly) generate an error 
message
if an error occurs. With my change, the result is:

   10 |   real(kind = k):: b = 4h1234
      |                      1
Error: Cannot simplify expression at (1)

That's with:

diff --git a/gcc/fortran/intrinsic.cc b/gcc/fortran/intrinsic.cc
index 64821c84543..b60d92a0665 100644
--- a/gcc/fortran/intrinsic.cc
+++ b/gcc/fortran/intrinsic.cc
@@ -27,2 +27,3 @@ along with GCC; see the file COPYING3.  If not see
 #include "intrinsic.h"
+#include "diagnostic.h" /* For errorcount.  */

@@ -4622,2 +4623,3 @@ do_simplify (gfc_intrinsic_sym *specific, gfc_expr *e)
   gfc_actual_arglist *arg;
+  int old_errorcount = errorcount;

@@ -4710,3 +4712,7 @@ finish:
   if (result == &gfc_bad_expr)
-    return false;
+    {
+      if (errorcount == old_errorcount)
+       gfc_error ("Cannot simplify expression at %L", &e->where);
+      return false;
+    }


Tobias

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