re PR target/88070 (ICE in create_pre_exit, at mode-switching.c:438)

	PR target/88070
	* mode-switching.c (create_pre_exit): After reload, always split the
	fallthrough edge to the exit block.

testsuite/ChangeLog:

	PR target/88070
	* gcc.target/i386/pr88070.c: New test.

From-SVN: r266326

1 files changed, 16 insertions, 2 deletions

diff --git a/gcc/mode-switching.c b/gcc/mode-switching.c
index 370a49e90a9..589fbeb0742 100644
--- a/gcc/mode-switching.c
+++ b/gcc/mode-switching.c
@@ -248,8 +248,22 @@ create_pre_exit (int n_entities, int *entity_map, const int *num_modes)
 	gcc_assert (!pre_exit);
 	/* If this function returns a value at the end, we have to
 	   insert the final mode switch before the return value copy
-	   to its hard register.  */
-	if (EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds) == 1
+	   to its hard register.
+
+	   x86 targets use mode-switching infrastructure to
+	   conditionally insert vzeroupper instruction at the exit
+	   from the function where there is no need to switch the
+	   mode before the return value copy.  The vzeroupper insertion
+	   pass runs after reload, so use !reload_completed as a stand-in
+	   for x86 to skip the search for the return value copy insn.
+
+	   N.b.: the code below assumes that the return copy insn
+	   immediately precedes its corresponding use insn.  This
+	   assumption does not hold after reload, since sched1 pass
+	   can schedule the return copy insn away from its
+	   corresponding use insn.  */
+	if (!reload_completed
+	    && EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds) == 1
 	    && NONJUMP_INSN_P ((last_insn = BB_END (src_bb)))
 	    && GET_CODE (PATTERN (last_insn)) == USE
 	    && GET_CODE ((ret_reg = XEXP (PATTERN (last_insn), 0))) == REG)