re PR tree-optimization/85712 (ICE in all_phi_incrs_profitable_1 at…

re PR tree-optimization/85712 (ICE in all_phi_incrs_profitable_1 at gcc/gimple-ssa-strength-reduction.c:3479)

2018-05-25  Bill Schmidt  <wschmidt@linux.ibm.com>

	PR tree-optimization/85712
	* gimple-ssa-strength-reduction.c (replace_one_candidate): Skip if
	this candidate has already been replaced in-situ by a copy.

From-SVN: r260772

gcc/ChangeLog

+2018-05-25  Bill Schmidt  <wschmidt@linux.ibm.com>
+
+	PR tree-optimization/85712
+	* gimple-ssa-strength-reduction.c (replace_one_candidate): Skip if
+	this candidate has already been replaced in-situ by a copy.
+
 2018-05-25  Jason Merrill  <jason@redhat.com>
 
         PR c++/80485 - inline function non-zero address.

gcc/gimple-ssa-strength-reduction.c

@@ -3662,6 +3662,11 @@ replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name)
   orig_rhs2 = gimple_assign_rhs2 (c->cand_stmt);
   cand_incr = cand_increment (c);
 
+  /* If orig_rhs2 is NULL, we have already replaced this in situ with
+     a copy statement under another interpretation.  */
+  if (!orig_rhs2)
+    return;
+
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
       fputs ("Replacing: ", dump_file);