re PR tree-optimization/77916 (ICE in verify_gimple_in_cfg: invalid (pointer)…

re PR tree-optimization/77916 (ICE in verify_gimple_in_cfg: invalid (pointer) operands to plus/minus)

2016-10-18  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/77916
	* gimple-ssa-strength-reduction.c (analyze_increments): Reinstate
	stopgap fix, as pointers with -1 increment are still broken.

From-SVN: r241305

gcc/ChangeLog

+2016-10-18  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/77916
+	* gimple-ssa-strength-reduction.c (analyze_increments): Reinstate
+	stopgap fix, as pointers with -1 increment are still broken.
+
 2016-10-18  David Edelsohn  <dje.gcc@gmail.com>
 
 	* config/rs6000/rs6000.c (rs6000_output_symbol_ref): Move storage

gcc/gimple-ssa-strength-reduction.c

@@ -2825,6 +2825,10 @@ analyze_increments (slsr_cand_t first_dep, machine_mode mode, bool speed)
 		   && !POINTER_TYPE_P (first_dep->cand_type)))
 	incr_vec[i].cost = COST_NEUTRAL;
 
+      /* FIXME: Still having trouble with pointers with a -1 increment.  */
+      else if (incr == -1 && POINTER_TYPE_P (first_dep->cand_type))
+	incr_vec[i].cost = COST_INFINITE;
+
       /* FORNOW: If we need to add an initializer, give up if a cast from
 	 the candidate's type to its stride's type can lose precision.
 	 This could eventually be handled better by expressly retaining the