New target check: vect_peeling_profitable

gcc/ChangeLog:

2017-10-04  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* doc/sourcebuild.texi: Document vect_peeling_profitable.

gcc/testsuite/ChangeLog:

2017-10-04  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* g++.dg/vect/slp-pr56812.cc: xfail for targets which don't want
	vector loop peeling.
	* lib/target-supports.exp (check_effective_target_vect_peeling_profitable):
	New proc.

From-SVN: r253407

gcc/ChangeLog

 2017-10-04  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
+	* doc/sourcebuild.texi: Document vect_peeling_profitable.
+
+2017-10-04  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
+
 	* doc/sourcebuild.texi: Document vect_intdouble_cvt and
 	vect_doubleint_cvt.
 

gcc/doc/sourcebuild.texi

@@ -1404,6 +1404,9 @@ Target supports a vector misalign access.
 @item vect_no_align
 Target does not support a vector alignment mechanism.
 
+@item vect_peeling_profitable
+Target might require to peel loops for alignment purposes.
+
 @item vect_no_int_min_max
 Target does not support a vector min and max instruction on @code{int}.
 

gcc/testsuite/ChangeLog

 2017-10-04  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
+	* g++.dg/vect/slp-pr56812.cc: xfail for targets which don't want
+	vector loop peeling.
+	* lib/target-supports.exp (check_effective_target_vect_peeling_profitable):
+	New proc.
+
+2017-10-04  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
+
 	* gcc.dg/vect/pr66251.c: Replace vect_floatint_cvt with
 	vect_doubleint_cvt and vect_intfloat_cvt with vect_intdouble_cvt.
 	* gcc.dg/vect/vect-floatint-conversion-2.c: Replace

gcc/testsuite/g++.dg/vect/slp-pr56812.cc

@@ -17,4 +17,6 @@ void mydata::Set (float x)
     data[i] = x;
 }
 
-/* { dg-final { scan-tree-dump-times "basic block vectorized" 1 "slp1" } } */
+/* For targets without vector loop peeling the loop becomes cheap
+   enough to be vectorized.  */
+/* { dg-final { scan-tree-dump-times "basic block vectorized" 1 "slp1" { xfail { ! vect_peeling_profitable } } } } */

gcc/testsuite/lib/target-supports.exp

@@ -3277,6 +3277,28 @@ proc check_effective_target_vect_floatuint_cvt { } {
     return $et_vect_floatuint_cvt_saved($et_index)
 }
 
+# Return 1 if peeling for alignment might be profitable on the target
+#
+
+proc check_effective_target_vect_peeling_profitable { } {
+    global et_vect_peeling_profitable_saved
+    global et_index
+
+    if [info exists et_vect_peeling_profitable_saved($et_index)] {
+	verbose "check_effective_target_vect_peeling_profitable: using cached result" 2
+    } else {
+	set et_vect_peeling_profitable_saved($et_index) 1
+        if { ([istarget s390*-*-*]
+	      && [check_effective_target_s390_vx]) } {
+	    set et_vect_peeling_profitable_saved($et_index) 0
+        }
+    }
+
+    verbose "check_effective_target_vect_peeling_profitable:\
+	     returning $et_vect_peeling_profitable_saved($et_index)" 2
+    return $et_vect_peeling_profitable_saved($et_index)
+}
+
 # Return 1 if the target supports #pragma omp declare simd, 0 otherwise.
 #
 # This won't change for different subtargets so cache the result.