[PR fortran/89516, patch] - ICE in gfc_calculate_transfer_sizes at gcc/fortran/check.c:5506

[PR fortran/89516, patch] - ICE in gfc_calculate_transfer_sizes at gcc/fortran/check.c:5506

[Harald Anlauf]

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Adding -Wsurprising as option to gfortran exercised a code path
that I hadn't seen when working on simplifications for the TRANSFER
intrinsic.  While regtesting, I realized that one of the checks was
too strict when the MOLD argument was scalar and of size 0 and should
only apply to array arguments.  I adjusted the corresponding testcase.

Regtested on x86_64-pc-linux-gnu.

OK for trunk?

Harald

2019-02-27  Harald Anlauf  <anlauf@gmx.de>

	PR fortran/89516
	* check.c (gfc_calculate_transfer_sizes): Correct checks for cases
	where storage size of elements of MOLD is 0.

2019-02-27  Harald Anlauf  <anlauf@gmx.de>

	PR fortran/89516
	* gfortran.dg/pr89492.f90: Adjust testcase.
	* gfortran.dg/transfer_check_5.f90: New test.


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Index: gcc/fortran/check.c
===================================================================
--- gcc/fortran/check.c	(revision 269264)
+++ gcc/fortran/check.c	(working copy)
@@ -5487,23 +5487,29 @@
   if (!gfc_element_size (mold, &result_elt_size))
     return false;
 
-  if (result_elt_size == 0 && *source_size > 0)
+  /* If the storage size of SOURCE is greater than zero and MOLD is an array,
+   * a scalar with the type and type parameters of MOLD shall not have a
+   * storage size equal to zero.
+   * If MOLD is a scalar and SIZE is absent, the result is a scalar.
+   * If MOLD is an array and SIZE is absent, the result is an array and of
+   * rank one. Its size is as small as possible such that its physical
+   * representation is not shorter than that of SOURCE.
+   * If SIZE is present, the result is an array of rank one and size SIZE.
+   */
+  if (result_elt_size == 0 && *source_size > 0 && !size
+      && mold->expr_type == EXPR_ARRAY)
     {
-      gfc_error ("%<MOLD%> argument of %<TRANSFER%> intrinsic at %L "
-                 "shall not have storage size 0 when %<SOURCE%> "
+      gfc_error ("%<MOLD%> argument of %<TRANSFER%> intrinsic at %L is an "
+		 "array and shall not have storage size 0 when %<SOURCE%> "
 		 "argument has size greater than 0", &mold->where);
       return false;
     }
 
-  /* If MOLD is a scalar and SIZE is absent, the result is a scalar.
-   * If MOLD is an array and SIZE is absent, the result is an array and of
-   * rank one. Its size is as small as possible such that its physical
-   * representation is not shorter than that of SOURCE.
-   */
   if (result_elt_size == 0 && *source_size == 0 && !size)
     {
       *result_size = 0;
-      *result_length_p = 0;
+      if (result_length_p)
+	*result_length_p = 0;
       return true;
     }
 

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Index: gcc/testsuite/gfortran.dg/pr89492.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pr89492.f90	(revision 269264)
+++ gcc/testsuite/gfortran.dg/pr89492.f90	(working copy)
@@ -19,9 +19,9 @@
   integer, parameter :: n(l) = l
   print *, k,i,l,m,j,n
   print *,      transfer(1,[''])                ! { dg-error "shall not have storage size 0" }
-  print *,      transfer(1, '' )                ! { dg-error "shall not have storage size 0" }
+  print *,      transfer(1, '' )                ! No error
   print *, size(transfer(1,['']))               ! { dg-error "shall not have storage size 0" }
-  print *, len (transfer(1, '' ))               ! { dg-error "shall not have storage size 0" }
+  print *, len (transfer(1, '' ))               ! No error
   print *, size(transfer([1],[bug4()]))         ! { dg-error "shall not have storage size 0" }
   print *, transfer(transfer([1],[bug4()]),[1]) ! { dg-error "shall not have storage size 0" }
 end program bug4a
Index: gcc/testsuite/gfortran.dg/transfer_check_5.f90
===================================================================
--- gcc/testsuite/gfortran.dg/transfer_check_5.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/transfer_check_5.f90	(working copy)
@@ -0,0 +1,14 @@
+! { dg-do compile }
+! { dg-options "-Wsurprising" }
+!
+! PR fortran/89516 - ICE in gfc_calculate_transfer_sizes at gcc/fortran/check.c:5506
+! Found by Martin Liška
+
+program test
+  character(*), parameter :: n = ''
+  character(*), parameter :: o = transfer ([''], n)
+  print *, transfer(1,'',size=0) ! No warning
+  print *, transfer(1,'',size=1) ! No warning
+  print *, transfer('',1,size=0) ! No warning
+  print *, transfer('',1,size=1) ! { dg-warning "has partly undefined result" }
+end program test

Re: [PR fortran/89516, patch] - ICE in gfc_calculate_transfer_sizes at gcc/fortran/check.c:5506

[Thomas Koenig]

Hi Harald,

> Adding -Wsurprising as option to gfortran exercised a code path
> that I hadn't seen when working on simplifications for the TRANSFER
> intrinsic.  While regtesting, I realized that one of the checks was
> too strict when the MOLD argument was scalar and of size 0 and should
> only apply to array arguments.  I adjusted the corresponding testcase.
> 
> Regtested on x86_64-pc-linux-gnu.
> 
> OK for trunk?

OK.

Thanks for the patch!

Regards

	Thomas

Re: [PR fortran/89516, patch] - ICE in gfc_calculate_transfer_sizes at gcc/fortran/check.c:5506

[Harald Anlauf]

Committed as rev. 269341 on trunk.

On 03/02/19 16:17, Thomas Koenig wrote:
> Hi Harald,
> 
>> Adding -Wsurprising as option to gfortran exercised a code path
>> that I hadn't seen when working on simplifications for the TRANSFER
>> intrinsic.  While regtesting, I realized that one of the checks was
>> too strict when the MOLD argument was scalar and of size 0 and should
>> only apply to array arguments.  I adjusted the corresponding testcase.
>>
>> Regtested on x86_64-pc-linux-gnu.
>>
>> OK for trunk?
> 
> OK.
> 
> Thanks for the patch!
> 
> Regards
> 
>     Thomas
>