[AVX-512ER] vrcp28ps auto generation

gcc/
	* config/i386/i386.c (ix86_emit_swdivsf): Emit vrcp28ps.
gcc/testsuite/
	* gcc.target/i386/avx512er-vrcp28ps-3.c: New test.
	* gcc.target/i386/avx512er-vrcp28ps-4.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@237648 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 78 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 26e8057db25..dacf8c16fe9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2016-06-21  Ilya Verbin  <ilya.verbin@intel.com>
+
+	* config/i386/i386.c (ix86_emit_swdivsf): Emit vrcp28ps.
+
 2016-06-21  H.J. Lu  <hongjiu.lu@intel.com>
 	    Ilya Enkovich  <ilya.enkovich@intel.com>
 
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 17664ff9f17..8139807512b 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -48726,8 +48726,19 @@ void ix86_emit_swdivsf (rtx res, rtx a, rtx b, machine_mode mode)
 
   /* x0 = rcp(b) estimate */
   if (mode == V16SFmode || mode == V8DFmode)
-    emit_insn (gen_rtx_SET (x0, gen_rtx_UNSPEC (mode, gen_rtvec (1, b),
-						UNSPEC_RCP14)));
+    {
+      if (TARGET_AVX512ER)
+	{
+	  emit_insn (gen_rtx_SET (x0, gen_rtx_UNSPEC (mode, gen_rtvec (1, b),
+						      UNSPEC_RCP28)));
+	  /* res = a * x0 */
+	  emit_insn (gen_rtx_SET (res, gen_rtx_MULT (mode, a, x0)));
+	  return;
+	}
+      else
+	emit_insn (gen_rtx_SET (x0, gen_rtx_UNSPEC (mode, gen_rtvec (1, b),
+						    UNSPEC_RCP14)));
+    }
   else
     emit_insn (gen_rtx_SET (x0, gen_rtx_UNSPEC (mode, gen_rtvec (1, b),
 						UNSPEC_RCP)));
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index cfee40b7572..cff25cc1979 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-06-21  Ilya Verbin  <ilya.verbin@intel.com>
+
+	* gcc.target/i386/avx512er-vrcp28ps-3.c: New test.
+	* gcc.target/i386/avx512er-vrcp28ps-4.c: New test.
+
 2016-06-21  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/71549
diff --git a/gcc/testsuite/gcc.target/i386/avx512er-vrcp28ps-3.c b/gcc/testsuite/gcc.target/i386/avx512er-vrcp28ps-3.c
new file mode 100644
index 00000000000..e08bea41c3e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/avx512er-vrcp28ps-3.c
@@ -0,0 +1,50 @@
+/* { dg-do run } */
+/* { dg-require-effective-target avx512er } */
+/* { dg-options "-O2 -ffast-math -ftree-vectorize -mavx512er" } */
+
+#include "avx512er-check.h"
+
+#define MAX 1000
+#define EPS 0.00001
+
+__attribute__ ((noinline, optimize (0)))
+void static
+compute_rcp_ref (float *a, float *b, float *r)
+{
+  for (int i = 0; i < MAX; i++)
+    r[i] = a[i] / b[i];
+}
+
+__attribute__ ((noinline))
+void static
+compute_rcp_exp (float *a, float *b, float *r)
+{
+  for (int i = 0; i < MAX; i++)
+    r[i] = a[i] / b[i];
+}
+
+void static
+avx512er_test (void)
+{
+  float a[MAX];
+  float b[MAX];
+  float ref[MAX];
+  float exp[MAX];
+
+  for (int i = 0; i < MAX; i++)
+    {
+      a[i] = 179.345 - 6.5645 * i;
+      b[i] = 8765.987 - 8.6756 * i;
+    }
+
+  compute_rcp_ref (a, b, ref);
+  compute_rcp_exp (a, b, exp);
+
+  for (int i = 0; i < MAX; i++)
+    {
+      float rel_err = (ref[i] - exp[i]) / ref[i];
+      rel_err = rel_err > 0.0 ? rel_err : -rel_err;
+      if (rel_err > EPS)
+	abort ();
+    }
+}
diff --git a/gcc/testsuite/gcc.target/i386/avx512er-vrcp28ps-4.c b/gcc/testsuite/gcc.target/i386/avx512er-vrcp28ps-4.c
new file mode 100644
index 00000000000..2c76d967184
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/avx512er-vrcp28ps-4.c
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -ftree-vectorize -mavx512er" } */
+
+#include "avx512er-vrcp28ps-3.c"
+
+/* { dg-final { scan-assembler-times "vrcp28ps\[^\n\r\]*zmm\[0-9\]+(?:\n|\[ \\t\]+#)" 1 } } */