[gcc r13-5089] tree-optimization/108314 - avoid BIT_NOT optimization for extract-last

[Richard Biener <rguenth@gcc.gnu.org>]

https://gcc.gnu.org/g:554bb9b61e2b76d4ace16a3f766b98ea887b17f4

commit r13-5089-g554bb9b61e2b76d4ace16a3f766b98ea887b17f4
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jan 10 10:42:21 2023 +0100

    tree-optimization/108314 - avoid BIT_NOT optimization for extract-last
    
    The extract-last reduction internal function expects the then and
    else clause as vector and scalar and thus we cannot perform optimization
    of the inversion of the condition by swapping the then/else clauses.
    
            PR tree-optimization/108314
            * tree-vect-stmts.cc (vectorizable_condition): Do not
            perform BIT_NOT_EXPR optimization for EXTRACT_LAST_REDUCTION.
    
            * gcc.dg/vect/pr108314.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/vect/pr108314.c | 16 ++++++++++++++++
 gcc/tree-vect-stmts.cc               | 13 +++++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/vect/pr108314.c b/gcc/testsuite/gcc.dg/vect/pr108314.c
new file mode 100644
index 00000000000..07260e06915
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr108314.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-march=armv9-a" { target aarch64-*-* } } */
+
+int x, y, z;
+
+void f(void)
+{
+  int t = 4;
+  for (; x; x++)
+    {
+      if (y)
+	continue;
+      t = 0;
+    }
+  z = t;
+}
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 6ddd41fb473..eb4ca1f184e 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -10677,7 +10677,8 @@ vectorizable_condition (vec_info *vinfo,
 	      vect_finish_stmt_generation (vinfo, stmt_info, new_stmt, gsi);
 	      if (bitop2 == NOP_EXPR)
 		vec_compare = new_temp;
-	      else if (bitop2 == BIT_NOT_EXPR)
+	      else if (bitop2 == BIT_NOT_EXPR
+		       && reduction_type != EXTRACT_LAST_REDUCTION)
 		{
 		  /* Instead of doing ~x ? y : z do x ? z : y.  */
 		  vec_compare = new_temp;
@@ -10686,9 +10687,13 @@ vectorizable_condition (vec_info *vinfo,
 	      else
 		{
 		  vec_compare = make_ssa_name (vec_cmp_type);
-		  new_stmt
-		    = gimple_build_assign (vec_compare, bitop2,
-					   vec_cond_lhs, new_temp);
+		  if (bitop2 == BIT_NOT_EXPR)
+		    new_stmt
+		      = gimple_build_assign (vec_compare, bitop2, new_temp);
+		  else
+		    new_stmt
+		      = gimple_build_assign (vec_compare, bitop2,
+					     vec_cond_lhs, new_temp);
 		  vect_finish_stmt_generation (vinfo, stmt_info,
 					       new_stmt, gsi);
 		}