http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59817
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- The ICE tells us that the parameter isn't recorded as parameter in the SESE region: (gdb) p debug_scop_params (s, 2) # parameters ( # Parameter names are provided 1 # Parameter names _10 pretmp_30 offset.3_15 #) $28 = void (gdb) p debug_scop_params (s, 5) # parameters ( # Parameter names are provided 1 # Parameter names _10 pretmp_30 offset.3_15 #) $29 = void (gdb) p debug_scop (s, 1) SCoP 1 #( # Language Gimple # Context ( #eq p0 p1 p2 cst XXX isl # ) # Parameter names are provided 1 # Parameter names _10 pretmp_30 offset.3_15 # Number of statements 2 # Iteration domain of bb_8 ( #eq i0 p0 p1 p2 cst XXX isl #) # Access informations are provided 1 # Read access informations 0 # Write access informations 1 # data accesses ( # eq alias sub0 i0 p0 p1 p2 cst #) # Statement body is not provided 0 # Iteration domain of bb_10 ( #eq i0 i1 p0 p1 p2 cst XXX isl #) # Access informations are not provided 0 # Statement body is not provided 0 #) $32 = void not sure if I interpret the above correctly but bb8 and bb10 seem to be in that scop. The parameter is refered from bb 8. Ah, scan_tree_for_params does scan_tree_for_params (sese s, tree e) { if (e == chrec_dont_know) return; switch (TREE_CODE (e)) { case POLYNOMIAL_CHREC: scan_tree_for_params (s, CHREC_LEFT (e)); break; thus it misses to scan CHREC_RIGHT. The MULT_EXPR handling is also suspicious. Fixing the above shifts the ICE to #1 0x000000000132e1ae in extract_affine_chrec (s=0x1f89e10, e= <polynomial_chrec 0x7ffff6d91ae0>, space=0x1f8b910) at /space/rguenther/src/svn/trunk/gcc/graphite-sese-to-poly.c:619 619 gcc_assert (isl_pw_aff_is_cst (rhs) (gdb) l 614 isl_aff *loop = isl_aff_set_coefficient_si 615 (isl_aff_zero_on_domain (ls), isl_dim_in, pos, 1); 616 isl_pw_aff *l = isl_pw_aff_from_aff (loop); 617 618 /* Before multiplying, make sure that the result is affine. */ 619 gcc_assert (isl_pw_aff_is_cst (rhs) 620 || isl_pw_aff_is_cst (l)); 621 622 return isl_pw_aff_add (lhs, isl_pw_aff_mul (rhs, l)); 623 } so maybe it simply doesn't handle CHRECs with variable stride but fails to disregard those. It indeed fails to as scev_is_linear_expression doesn't have the same restriction on CHRECs as graphite_can_represent_scev asserts. Thus completing that one as well is required. Index: gcc/graphite-scop-detection.c =================================================================== --- gcc/graphite-scop-detection.c (revision 209292) +++ gcc/graphite-scop-detection.c (working copy) @@ -219,7 +219,14 @@ graphite_can_represent_scev (tree scev) switch (TREE_CODE (scev)) { + case NEGATE_EXPR: + case BIT_NOT_EXPR: + CASE_CONVERT: + case NON_LVALUE_EXPR: + return graphite_can_represent_scev (TREE_OPERAND (scev, 0)); + case PLUS_EXPR: + case POINTER_PLUS_EXPR: case MINUS_EXPR: return graphite_can_represent_scev (TREE_OPERAND (scev, 0)) && graphite_can_represent_scev (TREE_OPERAND (scev, 1)); @@ -247,7 +254,8 @@ graphite_can_represent_scev (tree scev) } /* Only affine functions can be represented. */ - if (!scev_is_linear_expression (scev)) + if (tree_contains_chrecs (scev, NULL) + || !scev_is_linear_expression (scev)) return false; return true;