Hello world, the attached patch fixes another occurence of PR 79956. In this case, we did
sdim = GFC_DESCRIPTOR_RANK (source); .. for (n = 0; n < sdim; n++) { sstride[n] = GFC_DESCRIPTOR_STRIDE(source,n) } Now, we know that sdim can never be zero or lower, but the compiler doesn't, so it warned. (Why that didn't happen on x86_64 is an unsolved mystery so far). So, the attached patch inserts a call to internal_error when sdim is lower than one. Regression-tested. OK for trunk? Thomas 2017-03-12 Thomas Koenig <tkoe...@gcc.gnu.org> PR libfortran/79956 * m4/reshape.m4 (reshape_'rtype_ccode`): Add check for sdim < 1 so that later assignment from sstride[0] does not cause problems. * 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 +232,12 @@ reshape_c10 (gfc_array_c10 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_c16 (gfc_array_c16 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_c4 (gfc_array_c4 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_c8 (gfc_array_c8 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_16 (gfc_array_i16 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_4 (gfc_array_i4 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_8 (gfc_array_i8 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_r10 (gfc_array_r10 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_r16 (gfc_array_r16 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_r4 (gfc_array_r4 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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 +232,12 @@ reshape_r8 (gfc_array_r8 * const restrict ret, } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + 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) @@ -158,6 +158,12 @@ reshape_internal (parray *ret, parray *source, sha source_extent = 1; sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + for (n = 0; n < sdim; n++) { index_type se; Index: m4/reshape.m4 =================================================================== --- m4/reshape.m4 (Revision 245760) +++ m4/reshape.m4 (Arbeitskopie) @@ -236,6 +236,12 @@ reshape_'rtype_ccode` ('rtype` * const restrict re } sdim = GFC_DESCRIPTOR_RANK (source); + + /* This is needed so that gcc knows that n is at least one, + and that sstride[0] is always initialized. */ + if (sdim < 1) + internal_error (NULL, "Source array cannot be scalar"); + ssize = 1; sempty = 0; for (n = 0; n < sdim; n++)