Re: [Fortran, Patch, PR72698, v1] [5/6/7 Regression] ICE in lhd_incomplete_type_error, at langhooks.c:205

[Andre Vehreschild <vehre at gmx dot de>]

Hi Thomas,

thanks for the review. I have changed the test to run and result check
as requested. Committed to trunk as r239236.

Will commit to gcc-6 and -5-branch in one week.

Regards,
	Andre

On Mon, 8 Aug 2016 08:42:08 +0200
Thomas Koenig <tkoenig@netcologne.de> wrote:

> Am 07.08.2016 um 13:52 schrieb Andre Vehreschild:
> Hi Andre,
> 
> > attached patch fixes the ICE caused by a zero-sized string.
> > Assigning that string to a temporary variable obviously did not
> > work out. The patch fixes this by checking for zero-sized strings
> > in SOURCE= and not producing the code to assign "nothing" to the
> > temporary variable and later to the allocated memory. The version
> > for gcc-5 had to be adapted slightly, because the version of the
> > ALLOCATE() implementation is way behind.
> >
> > Bootstrapped and regtested on x86_64-linux-gnu/F23. Ok for trunk,
> > gcc-6 and gcc-5?  
> 
> Looks good.
> 
> With the test case, you might consider changing that into a runtime
> test to make sure that the correct result is obtained.
> 
> So, OK with that change.
> 
> Regards
> 
> 	Thomas
> 


-- 
Andre Vehreschild * Email: vehre ad gmx dot de 

Index: gcc/fortran/ChangeLog
===================================================================
--- gcc/fortran/ChangeLog	(Revision 239235)
+++ gcc/fortran/ChangeLog	(Arbeitskopie)
@@ -1,5 +1,11 @@
 2016-08-08  Andre Vehreschild  <vehre@gcc.gnu.org>
 
+	PR fortran/72698
+	* trans-stmt.c (gfc_trans_allocate): Prevent generating code for
+	copy of zero sized string and with it an ICE.
+
+2016-08-08  Andre Vehreschild  <vehre@gcc.gnu.org>
+
 	PR fortran/70524
 	* trans-array.c (gfc_trans_dummy_array_bias): Ensure that the
 	location information is correctly set.
Index: gcc/fortran/trans-stmt.c
===================================================================
--- gcc/fortran/trans-stmt.c	(Revision 239235)
+++ gcc/fortran/trans-stmt.c	(Arbeitskopie)
@@ -5448,9 +5448,19 @@
 	}
       gfc_add_block_to_block (&block, &se.pre);
       gfc_add_block_to_block (&post, &se.post);
+
+      /* Special case when string in expr3 is zero.  */
+      if (code->expr3->ts.type == BT_CHARACTER
+	  && integer_zerop (se.string_length))
+	{
+	  gfc_init_se (&se, NULL);
+	  temp_var_needed = false;
+	  expr3_len = integer_zero_node;
+	  e3_is = E3_MOLD;
+	}
       /* Prevent aliasing, i.e., se.expr may be already a
 	     variable declaration.  */
-      if (se.expr != NULL_TREE && temp_var_needed)
+      else if (se.expr != NULL_TREE && temp_var_needed)
 	{
 	  tree var, desc;
 	  tmp = GFC_DESCRIPTOR_TYPE_P (TREE_TYPE (se.expr)) || is_coarray ?
@@ -5679,11 +5689,8 @@
       gcc_assert (expr3_esize);
       expr3_esize = fold_convert (sizetype, expr3_esize);
       if (e3_is == E3_MOLD)
-	{
-	  /* The expr3 is no longer valid after this point.  */
-	  expr3 = NULL_TREE;
-	  e3_is = E3_UNSET;
-	}
+	/* The expr3 is no longer valid after this point.  */
+	expr3 = NULL_TREE;
     }
   else if (code->ext.alloc.ts.type != BT_UNKNOWN)
     {
@@ -6012,7 +6019,7 @@
 			    fold_convert (TREE_TYPE (al_len),
 					  integer_zero_node));
 	}
-      if (code->expr3 && !code->expr3->mold)
+      if (code->expr3 && !code->expr3->mold && e3_is != E3_MOLD)
 	{
 	  /* Initialization via SOURCE block (or static default initializer).
 	     Classes need some special handling, so catch them first.  */
Index: gcc/testsuite/ChangeLog
===================================================================
--- gcc/testsuite/ChangeLog	(Revision 239235)
+++ gcc/testsuite/ChangeLog	(Arbeitskopie)
@@ -1,3 +1,8 @@
+2016-08-08  Andre Vehreschild  <vehre@gcc.gnu.org>
+
+	PR fortran/72698
+	* gfortran.dg/allocate_with_source_20.f03: New test.
+
 2016-08-08  Alan Modra  <amodra@gmail.com>
 
 	* gcc.c-torture/compile/pr72802.c: New.
Index: gcc/testsuite/gfortran.dg/allocate_with_source_20.f03
===================================================================
--- gcc/testsuite/gfortran.dg/allocate_with_source_20.f03	(nicht existent)
+++ gcc/testsuite/gfortran.dg/allocate_with_source_20.f03	(Arbeitskopie)
@@ -0,0 +1,21 @@
+! { dg-do run }
+
+! Check that PR72698 is fixed.
+! Contributed by Gerhard Steinmetz
+
+module m
+contains
+   integer function f()
+      f = 4
+   end
+end
+program p
+   use m
+   character(3), parameter :: c = 'abc'
+   character(:), allocatable :: z
+   allocate (z, source=repeat(c(2:1), f()))
+   if (len(z) /= 0) call abort()
+   if (z /= "") call abort()
+end
+
+