[mid-end][__RTL] Set global epilogue_completed in skip_pass

Set global epilogue_completed when skipping pro_and_epilogue pass

When compiling RTL functions marked to start at a pass after the reload
pass, `skip_pass` is used to mark the reload pass as having completed
since many patterns use the `reload_completed` variable to determine
whether to run or not.

Here we do the same for the `epilogue_completed` variable and the
pro_and_epilogue pass.

Also include a testcase that relies on the availability of a
define_split in the aarch64 backend that is conditioned on this
`epilogue_completed` variable.

regtest done on native aarch64
regtest done on native x64_86

gcc/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* passes.c (skip_pass): Set epilogue_completed if skipping the
	pro_and_epilogue pass.

gcc/testsuite/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* gcc.dg/rtl/aarch64/test-epilogue-set.c: New test.

From-SVN: r278285

gcc/ChangeLog

 2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>
 
+	* passes.c (skip_pass): Set epilogue_completed if skipping the
+	pro_and_epilogue pass.
+
+2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>
+
 	* passes.c (should_skip_pass_p): Always run "dfinish".
 
 2019-11-15  Richard Biener  <rguenther@suse.de>

gcc/passes.c

@@ -2400,6 +2400,11 @@ skip_pass (opt_pass *pass)
   if (strcmp (pass->name, "reload") == 0)
     reload_completed = 1;
 
+  /* Similar for pass "pro_and_epilogue" and the "epilogue_completed" global
+     variable.  */
+  if (strcmp (pass->name, "pro_and_epilogue") == 0)
+    epilogue_completed = 1;
+
   /* The INSN_ADDRESSES vec is normally set up by
      shorten_branches; set it up for the benefit of passes that
      run after this.  */

gcc/testsuite/ChangeLog

 2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>
 
+	* gcc.dg/rtl/aarch64/test-epilogue-set.c: New test.
+
+2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>
+
 	* gcc.dg/rtl/aarch64/missed-pass-error.c: New test.
 
 2019-11-15  Richard Biener  <rguenther@suse.de>

gcc/testsuite/gcc.dg/rtl/aarch64/test-epilogue-set.c

+/* { dg-do compile { target aarch64-*-* } } */
+
+/*
+   Should compile rather than ICE.
+   Compilation requires setting the "epilogue_completed" variable.
+ */
+int __RTL (startwith ("cprop_hardreg"))
+f ()
+{
+(function "f"
+  (insn-chain
+    (block 2
+      (edge-from entry (flags "FALLTHRU"))
+      (cnote 6 [bb 2] NOTE_INSN_BASIC_BLOCK)
+      (cinsn 100 (set (reg:DI x0)
+		  (plus:DI
+		   (reg:DI x1)
+		   (const_int 16777213))))
+      ;; Extra insn, to avoid all of the above from being deleted by DCE
+      (cinsn 10 (use (reg/i:DI x0)))
+      (edge-to exit (flags "FALLTHRU"))
+    ) ;; block 2
+  ) ;; insn-chain
+) ;; function
+}