Hi All,

There's no reason that the sign of the operands of dot-product have to all be
the same.  The only restriction really is that the sign of the multiplicands
are the same, however the sign between the multiplier and the accumulator need
not be the same.

The type of the overall operations should be determined by the sign of the
multiplicand which is already being done by optabs-tree.c.

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

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	* tree-vect-patterns.c (vect_recog_dot_prod_pattern): Remove sign check.

gcc/testsuite/ChangeLog:

	* gcc.dg/vect/vect-reduc-dot-2.c: Expect to pass.
	* gcc.dg/vect/vect-reduc-dot-3.c: Likewise.
	* gcc.dg/vect/vect-reduc-dot-6.c: Likewise.
	* gcc.dg/vect/vect-reduc-dot-7.c: Likewise.

--- inline copy of patch -- 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-2.c b/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-2.c
index 25757d2b6713b53a325979b96f89396dbf4675b8..2ebe98887a6072b9e674846af1df38cdc94258dd 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-2.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-2.c
@@ -6,5 +6,5 @@
 
 #include "vect-reduc-dot-1.c"
 
-/* { dg-final { scan-tree-dump-not "vect_recog_dot_prod_pattern: detected" "vect" } } */
+/* { dg-final { scan-tree-dump "vect_recog_dot_prod_pattern: detected" "vect" } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-3.c b/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-3.c
index b1deb64e186da99ef42cb687d107445c0b800bd8..6a6679d522350ab4c19836f5537119122f0e654e 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-3.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-3.c
@@ -6,5 +6,5 @@
 
 #include "vect-reduc-dot-1.c"
 
-/* { dg-final { scan-tree-dump-not "vect_recog_dot_prod_pattern: detected" "vect" } } */
+/* { dg-final { scan-tree-dump "vect_recog_dot_prod_pattern: detected" "vect" } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-6.c b/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-6.c
index b690c9f2eb18b34f4b147d779bb3da582e285399..0cd4b823643bd4fadd529b2fe4e1d664aa1159ad 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-6.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-6.c
@@ -6,5 +6,5 @@
 
 #include "vect-reduc-dot-1.c"
 
-/* { dg-final { scan-tree-dump-not "vect_recog_dot_prod_pattern: detected" "vect" } } */
+/* { dg-final { scan-tree-dump "vect_recog_dot_prod_pattern: detected" "vect" } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-7.c b/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-7.c
index 29e442e8bbf7176cf861518dc171a83d82967764..eefee2e2ca27d749cd3af2238723aeae4e60a429 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-7.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-reduc-dot-7.c
@@ -6,5 +6,5 @@
 
 #include "vect-reduc-dot-1.c"
 
-/* { dg-final { scan-tree-dump-not "vect_recog_dot_prod_pattern: detected" "vect" } } */
+/* { dg-final { scan-tree-dump "vect_recog_dot_prod_pattern: detected" "vect" } } */
 
diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c
index 803de3fc287371fa202610a55b17e2c8934672f3..441d6cd28c4eaded7abd756164890dbcffd2f3b8 100644
--- a/gcc/tree-vect-patterns.c
+++ b/gcc/tree-vect-patterns.c
@@ -946,7 +946,8 @@ vect_recog_dot_prod_pattern (vec_info *vinfo,
      In which
      - DX is double the size of X
      - DY is double the size of Y
-     - DX, DY, DPROD all have the same type
+     - DX, DY, DPROD all have the same type but the sign
+       between DX, DY and DPROD can differ.
      - sum is the same size of DPROD or bigger
      - sum has been recognized as a reduction variable.
 
@@ -988,12 +989,6 @@ vect_recog_dot_prod_pattern (vec_info *vinfo,
 			     false, 2, unprom0, &half_type))
     return NULL;
 
-  /* If there are two widening operations, make sure they agree on
-     the sign of the extension.  */
-  if (TYPE_PRECISION (unprom_mult.type) != TYPE_PRECISION (type)
-      && TYPE_SIGN (unprom_mult.type) != TYPE_SIGN (half_type))
-    return NULL;
-
   vect_pattern_detected ("vect_recog_dot_prod_pattern", last_stmt);
 
   tree half_vectype;


--