[10/10] Add a vect_masked_store target selector

[Richard Sandiford <richard.sandiford@linaro.org>]

This patch adds a target selector that says whether the target
supports IFN_MASK_STORE.


2017-11-03  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* doc/sourcebuild.texi (vect_masked_store): Document.

gcc/testsuite/
	* lib/target-supports.exp (check_effective_target_vect_masked_store):
	New proc.
	* gcc.dg/vect/vect-cselim-1.c (foo): Mention that the second loop
	is vectorizable with masked stores.  Update scan-tree-dump-times
	accordingly.

Index: gcc/doc/sourcebuild.texi
===================================================================
--- gcc/doc/sourcebuild.texi	2017-11-03 16:06:56.516976666 +0000
+++ gcc/doc/sourcebuild.texi	2017-11-03 16:07:00.028331940 +0000
@@ -1403,6 +1403,9 @@ Target supports hardware vectors of @cod
 @item vect_long_long
 Target supports hardware vectors of @code{long long}.
 
+@item vect_masked_store
+Target supports vector masked stores.
+
 @item vect_aligned_arrays
 Target aligns arrays to vector alignment boundary.
 
Index: gcc/testsuite/lib/target-supports.exp
===================================================================
--- gcc/testsuite/lib/target-supports.exp	2017-11-03 16:06:56.519977825 +0000
+++ gcc/testsuite/lib/target-supports.exp	2017-11-03 16:07:00.029332326 +0000
@@ -6433,6 +6433,12 @@ proc check_effective_target_vect_load_la
     return $et_vect_load_lanes
 }
 
+# Return 1 if the target supports vector masked stores.
+
+proc check_effective_target_vect_masked_store { } {
+    return 0
+}
+
 # Return 1 if the target supports vector conditional operations, 0 otherwise.
 
 proc check_effective_target_vect_condition { } {
Index: gcc/testsuite/gcc.dg/vect/vect-cselim-1.c
===================================================================
--- gcc/testsuite/gcc.dg/vect/vect-cselim-1.c	2015-06-02 23:53:38.000000000 +0100
+++ gcc/testsuite/gcc.dg/vect/vect-cselim-1.c	2017-11-03 16:07:00.028331940 +0000
@@ -38,7 +38,7 @@ foo ()
         }
     }
 
-  /* Not vectorizable.  */
+  /* Only vectorizable with masked stores.  */
   for (i = 0; i < N; i++)
     {
       c = in1[i].b;
@@ -82,4 +82,5 @@ main (void)
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { xfail { { vect_no_align && { ! vect_hw_misalign } } || { ! vect_strided2 } } } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { ! vect_masked_store } xfail { { vect_no_align && { ! vect_hw_misalign } } || { ! vect_strided2 } } } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 2 loops" 1 "vect" { target { vect_masked_store } } } } */