re PR rtl-optimization/87600 (Fix for PRs 86939 and 87479 causes build issues for several targets)

	PR rtl-optimization/87600
	* ira-lives (non_conflicting_reg_copy_p): Disable for non LRA targets.

From-SVN: r265113

gcc/ChangeLog

+2018-10-12  Peter Bergner  <bergner@linux.ibm.com>
+
+	PR rtl-optimization/87600
+	* ira-lives (non_conflicting_reg_copy_p): Disable for non LRA targets.
+
 2018-10-12  Paul Koning  <ni1d@arrl.net>
 
 	* doc/md.texi (doloop_end): Document that the pattern code may

gcc/ira-lives.c

@@ -1064,6 +1064,11 @@ find_call_crossed_cheap_reg (rtx_insn *insn)
 rtx
 non_conflicting_reg_copy_p (rtx_insn *insn)
 {
+  /* Reload has issues with overlapping pseudos being assigned to the
+     same hard register, so don't allow it.  See PR87600 for details.  */
+  if (!targetm.lra_p ())
+    return NULL_RTX;
+
   rtx set = single_set (insn);
 
   /* Disallow anything other than a simple register to register copy