Hi Haochen,

thanks for fixing 'gcc/fortran/target-memory.cc'.

But could you also include the 'gcc/fortran/intrinsic.cc' change
proposed in
https://gcc.gnu.org/pipermail/gcc-patches/2023-March/613030.html (and
acknowledged by Steve)?

This will replace "Unclassifiable statement" by "Cannot simplify
expression" which is a bit more helpful.

(After doing so, at least the dg-error in your testcase needs to be
updated; I assume that it won't affect other testcases, but that needs
to be checked. – And you should update the comment in the testcase as
well - and in text you will put in the commit log, if applicable.)

Additionally, Kewen suggested:
Since this test case is powerpc only, I think it can be moved to 
gcc/testsuite/gcc.target/powerpc/ppc-fortran.

Which sounds reasonable.


Otherwise it looks good to me.

On 03.03.23 10:12, HAO CHEN GUI wrote:
Hi,
   The patch escalates the failure when Hollerith constant to real conversion
fails in native_interpret_expr. It finally reports an "Unclassifiable
statement" error.

   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.

   Compared to last version, this version moves the mpfr_init after NULL tree
test and fixes the format problem according to Tobias's advice. Thanks a lot.

(The format issue was actually spotted by Bernhard.)

Thanks for working on this!

Tobias

PS: One can also discuss Steve's suggestion about deprecating Holleriths / 
guarding
the support behind some flag. But I think that's unrelated to this bug fix 
patch and
should be discussed/done separately.


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.

patch.diff
diff --git a/gcc/fortran/arith.cc b/gcc/fortran/arith.cc
index c0d12cfad9d..d3d38c7eb6a 100644
--- a/gcc/fortran/arith.cc
+++ b/gcc/fortran/arith.cc
@@ -2752,10 +2752,12 @@ gfc_hollerith2real (gfc_expr *src, int kind)
    result = gfc_get_constant_expr (BT_REAL, kind, &src->where);

    hollerith2representation (result, src);
-  gfc_interpret_float (kind, (unsigned char *) result->representation.string,
-                    result->representation.length, result->value.real);
-
-  return result;
+  if (gfc_interpret_float (kind,
+                        (unsigned char *) result->representation.string,
+                        result->representation.length, result->value.real))
+    return result;
+  else
+    return NULL;
  }

  /* Convert character to real.  The constant will be padded or truncated.  */
diff --git a/gcc/fortran/target-memory.cc b/gcc/fortran/target-memory.cc
index 7ce7d736629..0c47aa6b842 100644
--- a/gcc/fortran/target-memory.cc
+++ b/gcc/fortran/target-memory.cc
@@ -416,11 +416,14 @@ gfc_interpret_float (int kind, unsigned char *buffer, 
size_t buffer_size,
                   mpfr_t real)
  {
    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;
+
+  mpfr_init (real);
+  gfc_conv_tree_to_mpfr (real, source);
    return size_float (kind);
  }

diff --git a/gcc/testsuite/gfortran.dg/pr103628.f90 
b/gcc/testsuite/gfortran.dg/pr103628.f90
new file mode 100644
index 00000000000..e49aefc18fd
--- /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.
+
+program main
+  integer, parameter :: k = 16
+  real(kind = k):: b = 4h1234
+end program main
+
+! { dg-warning "Conversion from HOLLERITH" "warning" { target powerpc*-*-* } 
10 }
+! { dg-error "Unclassifiable statement" "error" { target powerpc*-*-* } 10 }
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