Hi All,

At the moment when the VEC_PERMs generated by this match.pd rule is generated
it creates two different SSA_NAMEs for the folded operand.  Because of this it
the permute switches from a single operand permute to a two operand permute and
the target may no longer support a permute for this.

This fixes it by ensuring we generate the same SSA_NAME for both operands.

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	PR tree-optimization/107717
	* match.pd: Ensure same SSA_NAME.

gcc/testsuite/ChangeLog:

	PR tree-optimization/107717
	* gcc.target/aarch64/sve2/pr107717.c: New test.

--- inline copy of patch -- 
diff --git a/gcc/match.pd b/gcc/match.pd
index 82f05bbc912e4f80f3984d930c4a8dcb010136e1..cd510d80d409a7c52ba2a78e2fd7df0fc85cab2b 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -8317,7 +8317,7 @@ and,
  (simplify
   (op (vec_perm @0 @0 @2) (vec_perm @1 @1 @2))
    (if (VECTOR_INTEGER_TYPE_P (type))
-    (vec_perm (op @0 @1) (op @0 @1) @2))))
+    (vec_perm (op@3 @0 @1) @3 @2))))
 
 /* Similar for float arithmetic when permutation constant covers
    all vector elements.  */
@@ -8356,4 +8356,4 @@ and,
 	 }
       }
       (if (full_perm_p)
-	(vec_perm (op @0 @1) (op @0 @1) @2))))))
+	(vec_perm (op@3 @0 @1) @3 @2))))))




--