[PATCH] tree-optimization/110436 - bogus live/relevant for unused pattern

[PATCH] tree-optimization/110436 - bogus live/relevant for unused pattern

[Richard Biener]

When we compute liveness and relevantness we have to make sure to
handle live but not relevant stmts in a way we can later vectorize
them.  When the stmt uses only operands that do not need vectorization
we can just leave such stmts in place - but not in the case they
are recognized as patterns.  Since we don't have a way to cancel
pattern recognition we have to force mark such stmts as relevant.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR tree-optimization/110436
	* tree-vect-stmts.cc (vect_mark_relevant): Expand dumping,
	force live but not relevant pattern stmts relevant.

	* gcc.dg/pr110436.c: New testcase.
---
 gcc/testsuite/gcc.dg/pr110436.c |  4 ++++
 gcc/tree-vect-stmts.cc          | 15 +++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/pr110436.c

diff --git a/gcc/testsuite/gcc.dg/pr110436.c b/gcc/testsuite/gcc.dg/pr110436.c
new file mode 100644
index 00000000000..8e63ca04cbe
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110436.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+#include "pr83089.c"
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index a0c39268bf0..c3e6f2d34ed 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -261,11 +261,26 @@ vect_mark_relevant (vec<stmt_vec_info> *worklist, stmt_vec_info stmt_info,
 	dump_printf_loc (MSG_NOTE, vect_location,
 			 "last stmt in pattern. don't mark"
 			 " relevant/live.\n");
+
       stmt_vec_info old_stmt_info = stmt_info;
       stmt_info = STMT_VINFO_RELATED_STMT (stmt_info);
       gcc_assert (STMT_VINFO_RELATED_STMT (stmt_info) == old_stmt_info);
       save_relevant = STMT_VINFO_RELEVANT (stmt_info);
       save_live_p = STMT_VINFO_LIVE_P (stmt_info);
+
+      if (live_p && relevant == vect_unused_in_scope)
+	{
+	  if (dump_enabled_p ())
+	    dump_printf_loc (MSG_NOTE, vect_location,
+			     "vec_stmt_relevant_p: forcing live patern stmt "
+			     "relevant.\n");
+	  relevant = vect_used_only_live;
+	}
+
+      if (dump_enabled_p ())
+	dump_printf_loc (MSG_NOTE, vect_location,
+			 "mark relevant %d, live %d: %G", relevant, live_p,
+			 stmt_info->stmt);
     }
 
   STMT_VINFO_LIVE_P (stmt_info) |= live_p;
-- 
2.35.3