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_r16.c	(Revision 245760)
+++ generated/reshape_r16.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_r16 (gfc_array_r16 * 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_r4.c
===================================================================
--- generated/reshape_r4.c	(Revision 245760)
+++ generated/reshape_r4.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_r4 (gfc_array_r4 * 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_r8.c
===================================================================
--- generated/reshape_r8.c	(Revision 245760)
+++ generated/reshape_r8.c	(Arbeitskopie)
@@ -232,6 +232,11 @@ reshape_r8 (gfc_array_r8 * 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: intrinsics/reshape_generic.c
===================================================================
--- intrinsics/reshape_generic.c	(Revision 245760)
+++ intrinsics/reshape_generic.c	(Arbeitskopie)
@@ -66,6 +66,10 @@ reshape_internal (parray *ret, parray *source, sha
   index_type shape_data[GFC_MAX_DIMENSIONS];
 
   rdim = GFC_DESCRIPTOR_EXTENT(shape,0);
+  /* rdim is always > 0; this lets the compiler optimize more and
+     avoids a warning.  */
+  GFC_ASSERT (rdim > 0);
+  
   if (rdim != GFC_DESCRIPTOR_RANK(ret))
     runtime_error("rank of return array incorrect in RESHAPE intrinsic");
 
@@ -158,6 +162,10 @@ reshape_internal (parray *ret, parray *source, sha
 
       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 +227,10 @@ reshape_internal (parray *ret, parray *source, sha
     }
 
   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: libgfortran.h
===================================================================
--- libgfortran.h	(Revision 245760)
+++ libgfortran.h	(Arbeitskopie)
@@ -111,7 +111,12 @@ typedef off_t gfc_offset;
 #define likely(x)       __builtin_expect(!!(x), 1)
 #define unlikely(x)     __builtin_expect(!!(x), 0)
 
+/* This macro can be used to annotate conditions which we know to
+   be true, so that the compiler can optimize based on the condition.  */
 
+#define GFC_ASSERT(EXPR)                                                \
+  ((void)(__builtin_expect (!(EXPR), 0) ? __builtin_unreachable (), 0 : 0))
+
 /* Make sure we have ptrdiff_t. */
 #ifndef HAVE_PTRDIFF_T
 typedef intptr_t ptrdiff_t;
Index: m4/reshape.m4
===================================================================
--- m4/reshape.m4	(Revision 245760)
+++ m4/reshape.m4	(Arbeitskopie)
@@ -236,6 +236,11 @@ reshape_'rtype_ccode` ('rtype` * const restrict re
     }
 
   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++)
