[gfortran,patch] Fix PACK, SPREAD and CSHIFT for zero-sized arrays

["François-Xavier Coudert" <fxcoudert at gmail dot com>]

Hi all,

Attached patch introduces special cases in the library helper
functions of PACK, SPREAD and CSHIFT intrinsics to take care of
zero-sized arrays. In current state, both three intrinsics just return
garbage when called with zero-sized argument(s).

> From my investigations, after that patch only RESHAPE will still
require some tweaking; all other transformational intrinsics are
working fine AFAICT. I've had this patch in my tree for long, but
didn't post it because I was trying to devise a fix for RESHAPE and
submit the whole thing; unfortunately, I haven't yet managed to do
that in more than a month, so it's time to submit this partial patch.

Bootstrapped and regtested on i686-linux, comes with a testcase. OK
for mainline (and 4.1 after some time)?

Thanks,
FX



:ADDPATCH fortran:
Index: intrinsics/cshift0.c
===================================================================
--- intrinsics/cshift0.c	(revision 115644)
+++ intrinsics/cshift0.c	(working copy)
@@ -144,8 +144,8 @@
   if (ret->data == NULL)
     {
       int i;
+      index_type arraysize = size0 ((array_t *)array);
 
-      ret->data = internal_malloc_size (size * size0 ((array_t *)array));
       ret->offset = 0;
       ret->dtype = array->dtype;
       for (i = 0; i < GFC_DESCRIPTOR_RANK (array); i++)
@@ -156,8 +156,17 @@
           if (i == 0)
             ret->dim[i].stride = 1;
           else
-            ret->dim[i].stride = (ret->dim[i-1].ubound + 1) * ret->dim[i-1].stride;
+            ret->dim[i].stride = (ret->dim[i-1].ubound + 1)
+				 * ret->dim[i-1].stride;
         }
+
+      if (arraysize > 0)
+	ret->data = internal_malloc_size (size * arraysize);
+      else
+	{
+	  ret->data = internal_malloc_size (1);
+	  return;
+	}
     }
 
   for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
Index: intrinsics/pack_generic.c
===================================================================
--- intrinsics/pack_generic.c	(revision 115644)
+++ intrinsics/pack_generic.c	(working copy)
@@ -195,12 +195,15 @@
       ret->dim[0].ubound = total - 1;
       ret->dim[0].stride = 1;
 
-      ret->data = internal_malloc_size (size * total);
       ret->offset = 0;
-
       if (total == 0)
-	/* In this case, nothing remains to be done.  */
-	return;
+	{
+	  /* In this case, nothing remains to be done.  */
+	  ret->data = internal_malloc_size (1);
+	  return;
+	}
+      else
+	ret->data = internal_malloc_size (size * total);
     }
 
   rstride0 = ret->dim[0].stride * size;
@@ -210,7 +213,7 @@
   mstride0 = mstride[0];
   rptr = ret->data;
 
-  while (sptr)
+  while (sptr && mptr)
     {
       /* Test this element.  */
       if (*mptr)
@@ -315,14 +318,17 @@
   index_type extent[GFC_MAX_DIMENSIONS];
   index_type n;
   index_type dim;
+  index_type ssize;
   index_type nelem;
 
   dim = GFC_DESCRIPTOR_RANK (array);
+  ssize = 1;
   for (n = 0; n < dim; n++)
     {
       count[n] = 0;
       extent[n] = array->dim[n].ubound + 1 - array->dim[n].lbound;
       sstride[n] = array->dim[n].stride * size;
+      ssize *= extent[n];
     }
   if (sstride[0] == 0)
     sstride[0] = size;
@@ -352,25 +358,23 @@
 		total *= extent[n];
 	    }
 	  else
-	    {
-	      /* The result array will be empty.  */
-	      ret->dim[0].lbound = 0;
-	      ret->dim[0].ubound = -1;
-	      ret->dim[0].stride = 1;
-	      ret->data = internal_malloc_size (0);
-	      ret->offset = 0;
-
-	      return;
-	    }
+	    /* The result array will be empty.  */
+	    total = 0;
 	}
 
       /* Setup the array descriptor.  */
       ret->dim[0].lbound = 0;
       ret->dim[0].ubound = total - 1;
       ret->dim[0].stride = 1;
+      ret->offset = 0;
 
-      ret->data = internal_malloc_size (size * total);
-      ret->offset = 0;
+      if (total == 0)
+	{
+	  ret->data = internal_malloc_size (1);
+	  return;
+	}
+      else
+	ret->data = internal_malloc_size (size * total);
     }
 
   rstride0 = ret->dim[0].stride * size;
@@ -384,7 +388,7 @@
        If MASK is .FALSE., we have to copy VECTOR into the result
      array. If VECTOR were not present we would have already returned.  */
 
-  if (*mask)
+  if (*mask && ssize != 0)
     {
       while (sptr)
 	{
Index: intrinsics/spread_generic.c
===================================================================
--- intrinsics/spread_generic.c	(revision 115644)
+++ intrinsics/spread_generic.c	(working copy)
@@ -101,7 +101,13 @@
 	    }
 	}
       ret->offset = 0;
-      ret->data = internal_malloc_size (rs * size);
+      if (rs > 0)
+        ret->data = internal_malloc_size (rs * size);
+      else
+	{
+	  ret->data = internal_malloc_size (1);
+	  return;
+	}
     }
   else
     {

Attachment: zero_sized.ChangeLog
Description: Binary data

! { dg-do run }
! Transformational functions for zero-sized array and array sections
! Contributed by Francois-Xavier Coudert  <coudert@clipper.ens.fr>

subroutine test_cshift
  real :: tempn(1), tempm(1,2)
  real,allocatable :: foo(:),bar(:,:),gee(:,:)
  tempn = 2.0
  tempm = 1.0
  allocate(foo(0),bar(2,0),gee(0,7))
  if (any(cshift(foo,dim=1,shift=1)/= 0)) call abort
  if (any(cshift(tempn(2:1),dim=1,shift=1)/= 0)) call abort
  if (any(cshift(bar,shift=(/1,-1/),dim=1)/= 0)) call abort
  if (any(cshift(bar,shift=(/1,-1/),dim=2)/= 0)) call abort
  if (any(cshift(gee,shift=(/1,-1/),dim=1)/= 0)) call abort
  if (any(cshift(gee,shift=(/1,-1/),dim=2)/= 0)) call abort
  if (any(cshift(tempm(5:4,:),shift=(/1,-1/),dim=1)/= 0)) call abort
  if (any(cshift(tempm(5:4,:),shift=(/1,-1/),dim=2)/= 0)) call abort
  if (any(cshift(tempm(:,5:4),shift=(/1,-1/),dim=1)/= 0)) call abort
  if (any(cshift(tempm(:,5:4),shift=(/1,-1/),dim=2)/= 0)) call abort
  deallocate(foo,bar,gee)
end

subroutine test_eoshift
  real :: tempn(1), tempm(1,2)
  real,allocatable :: foo(:),bar(:,:),gee(:,:)
  tempn = 2.0
  tempm = 1.0
  allocate(foo(0),bar(2,0),gee(0,7))
  if (any(eoshift(foo,dim=1,shift=1)/= 0)) call abort
  if (any(eoshift(tempn(2:1),dim=1,shift=1)/= 0)) call abort
  if (any(eoshift(bar,shift=(/1,-1/),dim=1)/= 0)) call abort
  if (any(eoshift(bar,shift=(/1,-1/),dim=2)/= 0)) call abort
  if (any(eoshift(gee,shift=(/1,-1/),dim=1)/= 0)) call abort
  if (any(eoshift(gee,shift=(/1,-1/),dim=2)/= 0)) call abort
  if (any(eoshift(tempm(5:4,:),shift=(/1,-1/),dim=1)/= 0)) call abort
  if (any(eoshift(tempm(5:4,:),shift=(/1,-1/),dim=2)/= 0)) call abort
  if (any(eoshift(tempm(:,5:4),shift=(/1,-1/),dim=1)/= 0)) call abort
  if (any(eoshift(tempm(:,5:4),shift=(/1,-1/),dim=2)/= 0)) call abort

  if (any(eoshift(foo,dim=1,shift=1,boundary=42.0)/= 0)) call abort
  if (any(eoshift(tempn(2:1),dim=1,shift=1,boundary=42.0)/= 0)) call abort
  if (any(eoshift(bar,shift=(/1,-1/),dim=1,boundary=42.0)/= 0)) call abort
  if (any(eoshift(bar,shift=(/1,-1/),dim=2,boundary=42.0)/= 0)) call abort
  if (any(eoshift(gee,shift=(/1,-1/),dim=1,boundary=42.0)/= 0)) call abort
  if (any(eoshift(gee,shift=(/1,-1/),dim=2,boundary=42.0)/= 0)) call abort
  if (any(eoshift(tempm(5:4,:),shift=(/1,-1/),dim=1,boundary=42.0)/= 0)) call abort
  if (any(eoshift(tempm(5:4,:),shift=(/1,-1/),dim=2,boundary=42.0)/= 0)) call abort
  if (any(eoshift(tempm(:,5:4),shift=(/1,-1/),dim=1,boundary=42.0)/= 0)) call abort
  if (any(eoshift(tempm(:,5:4),shift=(/1,-1/),dim=2,boundary=42.0)/= 0)) call abort

  if (any(eoshift(foo,dim=1,shift=1,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(tempn(2:1),dim=1,shift=1,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(bar,shift=(/1,-1/),dim=1,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(bar,shift=(/1,-1/),dim=2,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(gee,shift=(/1,-1/),dim=1,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(gee,shift=(/1,-1/),dim=2,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(tempm(5:4,:),shift=(/1,-1/),dim=1,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(tempm(5:4,:),shift=(/1,-1/),dim=2,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(tempm(:,5:4),shift=(/1,-1/),dim=1,boundary=(/42.0,-7.0/))/= 0)) call abort
  if (any(eoshift(tempm(:,5:4),shift=(/1,-1/),dim=2,boundary=(/42.0,-7.0/))/= 0)) call abort
  deallocate(foo,bar,gee)
end

subroutine test_transpose
  character(len=1) :: tempn(1,2)
  character(len=1),allocatable :: foo(:,:), bar(:,:)
  integer :: tempm(1,2)
  integer,allocatable :: x(:,:), y(:,:)
  tempn = 'a'
  allocate(foo(3,0),bar(-2:-4,7:9))
  tempm = -42
  allocate(x(3,0),y(-2:-4,7:9))
  if (any(transpose(tempn(-7:-8,:)) /= 'b')) call abort
  if (any(transpose(tempn(:,9:8)) /= 'b')) call abort
  if (any(transpose(foo) /= 'b')) call abort
  if (any(transpose(bar) /= 'b')) call abort
  if (any(transpose(tempm(-7:-8,:)) /= 0)) call abort
  if (any(transpose(tempm(:,9:8)) /= 0)) call abort
  if (any(transpose(x) /= 0)) call abort
  if (any(transpose(y) /= 0)) call abort
  deallocate(foo,bar,x,y)
end

subroutine test_reshape
  character(len=1) :: tempn(1,2)
  character(len=1),allocatable :: foo(:,:), bar(:,:)
  integer :: tempm(1,2)
  integer,allocatable :: x(:,:), y(:,:)
  tempn = 'b'
  tempm = -42
  allocate(foo(3,0),bar(-2:-4,7:9),x(3,0),y(-2:-4,7:9))
  
  if (size(reshape(tempn(-7:-8,:),(/3,3/),pad=(/'a'/))) /= 9 .or. &
      any(reshape(tempn(-7:-8,:),(/3,3/),pad=(/'a'/)) /= 'a')) call abort
  if (size(reshape(tempn(-7:-8,:),(/3,3,3/),pad=(/'a'/))) /= 27 .or. &
      any(reshape(tempn(-7:-8,:),(/3,3,3/),pad=(/'a'/)) /= 'a')) call abort
  if (size(reshape(tempn(-7:-8,:),(/3,3,3,3,3,3,3/),pad=(/'a'/))) /= 2187 .or. &
      any(reshape(tempn(-7:-8,:),(/3,3,3,3,3,3,3/),pad=(/'a'/)) /= 'a')) call abort
  if (size(reshape(foo,(/3,3/),pad=(/'a'/))) /= 9 .or. &
      any(reshape(foo,(/3,3/),pad=(/'a'/)) /= 'a')) call abort
  if (size(reshape(foo,(/3,3,3/),pad=(/'a'/))) /= 27 .or. &
      any(reshape(foo,(/3,3,3/),pad=(/'a'/)) /= 'a')) call abort
  if (size(reshape(foo,(/3,3,3,3,3,3,3/),pad=(/'a'/))) /= 2187 .or. &
      any(reshape(foo,(/3,3,3,3,3,3,3/),pad=(/'a'/)) /= 'a')) call abort
  if (size(reshape(bar,(/3,3/),pad=(/'a'/))) /= 9 .or. &
      any(reshape(bar,(/3,3/),pad=(/'a'/)) /= 'a')) call abort
  if (size(reshape(bar,(/3,3,3/),pad=(/'a'/))) /= 27 .or. &
      any(reshape(bar,(/3,3,3/),pad=(/'a'/)) /= 'a')) call abort
  if (size(reshape(bar,(/3,3,3,3,3,3,3/),pad=(/'a'/))) /= 2187 .or. &
      any(reshape(bar,(/3,3,3,3,3,3,3/),pad=(/'a'/)) /= 'a')) call abort

  if (size(reshape(tempm(-7:-8,:),(/3,3/),pad=(/7/))) /= 9 .or. &
      any(reshape(tempm(-7:-8,:),(/3,3/),pad=(/7/)) /= 7)) call abort
  if (size(reshape(tempm(-7:-8,:),(/3,3,3/),pad=(/7/))) /= 27 .or. &
      any(reshape(tempm(-7:-8,:),(/3,3,3/),pad=(/7/)) /= 7)) call abort
  if (size(reshape(tempm(-7:-8,:),(/3,3,3,3,3,3,3/),pad=(/7/))) /= 2187 .or. &
      any(reshape(tempm(-7:-8,:),(/3,3,3,3,3,3,3/),pad=(/7/)) /= 7)) call abort
  if (size(reshape(x,(/3,3/),pad=(/7/))) /= 9 .or. &
      any(reshape(x,(/3,3/),pad=(/7/)) /= 7)) call abort
  if (size(reshape(x,(/3,3,3/),pad=(/7/))) /= 27 .or. &
      any(reshape(x,(/3,3,3/),pad=(/7/)) /= 7)) call abort
  if (size(reshape(x,(/3,3,3,3,3,3,3/),pad=(/7/))) /= 2187 .or. &
      any(reshape(x,(/3,3,3,3,3,3,3/),pad=(/7/)) /= 7)) call abort
  if (size(reshape(y,(/3,3/),pad=(/7/))) /= 9 .or. &
      any(reshape(y,(/3,3/),pad=(/7/)) /= 7)) call abort
  if (size(reshape(y,(/3,3,3/),pad=(/7/))) /= 27 .or. &
      any(reshape(y,(/3,3,3/),pad=(/7/)) /= 7)) call abort
  if (size(reshape(y,(/3,3,3,3,3,3,3/),pad=(/7/))) /= 2187 .or. &
      any(reshape(y,(/3,3,3,3,3,3,3/),pad=(/7/)) /= 7)) call abort

  deallocate(foo,bar,x,y)
end

subroutine test_pack
  integer :: tempn(1,5)
  integer,allocatable :: foo(:,:)
  tempn = 2 
  allocate(foo(0,1:7))
  if (size(pack(foo,foo/=0)) /= 0 .or. any(pack(foo,foo/=0) /= -42)) call abort
  if (size(pack(foo,foo/=0,(/1,3,4,5,1,0,7,9/))) /= 8 .or. &
      sum(pack(foo,foo/=0,(/1,3,4,5,1,0,7,9/))) /= 30) call abort
  if (size(pack(tempn(:,-4:-5),tempn(:,-4:-5)/=0)) /= 0 .or. &
      any(pack(tempn(:,-4:-5),tempn(:,-4:-5)/=0) /= -42)) call abort
  if (size(pack(tempn(:,-4:-5),tempn(:,-4:-5)/=0,(/1,3,4,5,1,0,7,9/))) /= 8 .or. &
      sum(pack(tempn(:,-4:-5),tempn(:,-4:-5)/=0,(/1,3,4,5,1,0,7,9/))) /= 30) &
    call abort
  if (size(pack(foo,.true.)) /= 0 .or. any(pack(foo,.true.) /= -42)) &
    call abort
  if (size(pack(foo,.true.,(/1,3,4,5,1,0,7,9/))) /= 8 .or. &
      sum(pack(foo,.true.,(/1,3,4,5,1,0,7,9/))) /= 30) call abort
  if (size(pack(tempn(:,-4:-5),.true.)) /= 0 .or. &
      any(pack(foo,.true.) /= -42)) call abort
  if (size(pack(tempn(:,-4:-5),.true.,(/1,3,4,5,1,0,7,9/))) /= 8 .or. &
      sum(pack(tempn(:,-4:-5),.true.,(/1,3,4,5,1,0,7,9/))) /= 30) call abort
  deallocate(foo)
end

subroutine test_unpack
  integer :: tempn(1,5), tempv(5)
  integer,allocatable :: foo(:,:), bar(:)
  tempn = 2 
  tempv = 5
  allocate(foo(0,1:7),bar(0:-1))
  if (any(unpack(tempv,tempv/=0,tempv) /= 5) .or. &
      size(unpack(tempv,tempv/=0,tempv)) /= 5) call abort
  if (any(unpack(tempv(1:0),tempv/=0,tempv) /= 5) .or. &
      size(unpack(tempv(1:0),tempv/=0,tempv)) /= 5) call abort
  if (any(unpack(tempv,tempv(1:0)/=0,tempv) /= -47)) call abort
  if (any(unpack(tempv(5:4),tempv(1:0)/=0,tempv) /= -47)) call abort
  if (any(unpack(bar,foo==foo,foo) /= -47)) call abort
  deallocate(foo,bar)
end

subroutine test_spread
  real :: tempn(1)
  real,allocatable :: foo(:)
  tempn = 2.0 
  allocate(foo(0))
  if (any(spread(1,dim=1,ncopies=0) /= -17.0) .or. &
      size(spread(1,dim=1,ncopies=0)) /= 0) call abort
  if (any(spread(foo,dim=1,ncopies=1) /= -17.0) .or. &
      size(spread(foo,dim=1,ncopies=1)) /= 0) call abort
  if (any(spread(tempn(2:1),dim=1,ncopies=1) /= -17.0) .or. &
      size(spread(tempn(2:1),dim=1,ncopies=1)) /= 0) call abort
  deallocate(foo)
end

program test
  call test_cshift
  call test_eoshift
  call test_transpose
  call test_unpack
  call test_spread
  call test_pack
!  call test_reshape
end