[patch, libfortran] [patch, fortran] Fix PR 79956, part two, attempt 2

[Thomas Koenig]

Hello world,

Following Richard's suggestion, I have implemented the GFC_ASSERT macro
and used it to (hopefully) silence the ominous warning and allow
further optimization.

OK for trunk?

Regards

Thomas

2017-03-12  Thomas Koenig  

PR libfortran/79956
* libgfortran.h (GFC_ASSERT):  New macro.
* m4/reshape.m4 (reshape_'rtype_ccode`):  Use GFC_ASSERT
to specify that sdim > 0.
* intrinsic/reshape_generic.c (reshape_internal):  Likweise.
* generated/reshape_c10.c: Regenerated.
* generated/reshape_c16.c: Regenerated.
* generated/reshape_c4.c: Regenerated.
* generated/reshape_c8.c: Regenerated.
* generated/reshape_i16.c: Regenerated.
* generated/reshape_i4.c: Regenerated.
* generated/reshape_i8.c: Regenerated.
* generated/reshape_r10.c: Regenerated.
* generated/reshape_r16.c: Regenerated.
* generated/reshape_r4.c: Regenerated.
* generated/reshape_r8.c: Regenerated.
Index: generated/reshape_c10.c
===
--- generated/reshape_c10.c	(Revision 245760)
+++ generated/reshape_c10.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_c10 (gfc_array_c10 * const restrict ret,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  /* sdim is always > 0; this lets the compiler optimize more and
+   avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)
Index: generated/reshape_c16.c
===
--- generated/reshape_c16.c	(Revision 245760)
+++ generated/reshape_c16.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_c16 (gfc_array_c16 * const restrict ret,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  /* sdim is always > 0; this lets the compiler optimize more and
+   avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)
Index: generated/reshape_c4.c
===
--- generated/reshape_c4.c	(Revision 245760)
+++ generated/reshape_c4.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_c4 (gfc_array_c4 * const restrict ret,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  /* sdim is always > 0; this lets the compiler optimize more and
+   avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)
Index: generated/reshape_c8.c
===
--- generated/reshape_c8.c	(Revision 245760)
+++ generated/reshape_c8.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_c8 (gfc_array_c8 * const restrict ret,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  /* sdim is always > 0; this lets the compiler optimize more and
+   avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)
Index: generated/reshape_i16.c
===
--- generated/reshape_i16.c	(Revision 245760)
+++ generated/reshape_i16.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_16 (gfc_array_i16 * const restrict ret,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  /* sdim is always > 0; this lets the compiler optimize more and
+   avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)
Index: generated/reshape_i4.c
===
--- generated/reshape_i4.c	(Revision 245760)
+++ generated/reshape_i4.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_4 (gfc_array_i4 * const restrict ret,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  /* sdim is always > 0; this lets the compiler optimize more and
+   avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)
Index: generated/reshape_i8.c
===
--- generated/reshape_i8.c	(Revision 245760)
+++ generated/reshape_i8.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_8 (gfc_array_i8 * const restrict ret,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  /* sdim is always > 0; this lets the compiler optimize more and
+   avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)
Index: generated/reshape_r10.c
===
--- generated/reshape_r10.c	(Revision 245760)
+++ generated/reshape_r10.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_r10 (gfc_array_r10 * const restrict ret,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  /* sdim is always > 0; this lets the compiler optimize more and
+   avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)
Index: generated/reshape_r16.c
===
--- generated/reshape_r

Re: [patch, libfortran] [patch, fortran] Fix PR 79956, part two, attempt 2

[Markus Trippelsdorf]

On 2017.03.13 at 23:24 +0100, Thomas Koenig wrote:
> Hello world,
> 
> Following Richard's suggestion, I have implemented the GFC_ASSERT macro
> and used it to (hopefully) silence the ominous warning and allow
> further optimization.

Unfortunately the single GFC_ASSERT isn't enough:

libgfortran/intrinsics/reshape_generic.c: In function ‘reshape_internal’:
libgfortran/intrinsics/reshape_generic.c:257:21: warning: ‘sstride[0]’ may be 
used uninitialized in this function [-Wmaybe-uninitialized]
   sstride0 = sstride[0] * size;
  ~~~^~~
The following patch is needed to silence them all.

diff --git a/libgfortran/intrinsics/reshape_generic.c 
b/libgfortran/intrinsics/reshape_generic.c
index 43a822f87ae..d7c9e74853a 100644
--- a/libgfortran/intrinsics/reshape_generic.c
+++ b/libgfortran/intrinsics/reshape_generic.c
@@ -66,6 +66,7 @@ reshape_internal (parray *ret, parray *source, shape_type 
*shape,
   index_type shape_data[GFC_MAX_DIMENSIONS];
 
   rdim = GFC_DESCRIPTOR_EXTENT(shape,0);
+  GFC_ASSERT(rdim>0);
   if (rdim != GFC_DESCRIPTOR_RANK(ret))
 runtime_error("rank of return array incorrect in RESHAPE intrinsic");
 
@@ -158,6 +159,10 @@ reshape_internal (parray *ret, parray *source, shape_type 
*shape,
 
   source_extent = 1;
   sdim = GFC_DESCRIPTOR_RANK (source);
+  /* sdim is always > 0; this lets the compiler optimize more and
+ avoids a warning.  */
+  GFC_ASSERT(sdim>0);
+
   for (n = 0; n < sdim; n++)
{
  index_type se;
@@ -219,6 +224,7 @@ reshape_internal (parray *ret, parray *source, shape_type 
*shape,
 }
 
   sdim = GFC_DESCRIPTOR_RANK (source);
+  GFC_ASSERT(sdim>0);
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)

-- 
Markus