Re: [PATCH 09/25] Elide repeated RTL elements.

[Andrew Stubbs <ams@codesourcery.com>]

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On 19/09/18 17:38, Andrew Stubbs wrote:
> Here's an updated patch incorporating the RTL front-end changes. I had 
> to change from "repeated 2x" to "repeated x2" because the former is not 
> a valid C token, and apparently that's important.

Here's a patch with self tests added, for both reading and writing.

It also fixes a bug when the repeat was the last item in a list.

OK?

Andrew

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Elide repeated RTL elements.

GCN's 64-lane vectors tend to make RTL dumps very long.  This patch makes them
far more bearable by eliding long sequences of the same element into "repeated"
messages.

This also takes care of reading repeated sequences in the RTL front-end.

There are self tests for both reading and writing.

2018-09-20  Andrew Stubbs  <ams@codesourcery.com>
	    Jan Hubicka  <jh@suse.cz>
	    Martin Jambor  <mjambor@suse.cz>

	gcc/
	* print-rtl.c (print_rtx_operand_codes_E_and_V): Print how many times
	the same elements are repeated rather than printing all of them.
	* read-rtl.c (rtx_reader::read_rtx_operand): Recognize and expand
	"repeated" elements.
	* read-rtl-function.c (test_loading_repeat): New function.
	(read_rtl_function_c_tests): Call test_loading_repeat.
	* rtl-tests.c (test_dumping_repeat): New function.
	(rtl_tests_c_tests): Call test_dumping_repeat.

	gcc/testsuite/
	* selftests/repeat.rtl: New file.

diff --git a/gcc/print-rtl.c b/gcc/print-rtl.c
index 5dd2e31..1228483 100644
--- a/gcc/print-rtl.c
+++ b/gcc/print-rtl.c
@@ -370,7 +370,20 @@ rtx_writer::print_rtx_operand_codes_E_and_V (const_rtx in_rtx, int idx)
 	m_sawclose = 1;
 
       for (int j = 0; j < XVECLEN (in_rtx, idx); j++)
-	print_rtx (XVECEXP (in_rtx, idx, j));
+	{
+	  int j1;
+
+	  print_rtx (XVECEXP (in_rtx, idx, j));
+	  for (j1 = j + 1; j1 < XVECLEN (in_rtx, idx); j1++)
+	    if (XVECEXP (in_rtx, idx, j) != XVECEXP (in_rtx, idx, j1))
+	      break;
+
+	  if (j1 != j + 1)
+	    {
+	      fprintf (m_outfile, " repeated x%i", j1 - j);
+	      j = j1 - 1;
+	    }
+	}
 
       m_indent -= 2;
     }
diff --git a/gcc/read-rtl-function.c b/gcc/read-rtl-function.c
index cde9d3e..8746f70 100644
--- a/gcc/read-rtl-function.c
+++ b/gcc/read-rtl-function.c
@@ -2166,6 +2166,20 @@ test_loading_mem ()
   ASSERT_EQ (6, MEM_ADDR_SPACE (mem2));
 }
 
+/* Verify that "repeated xN" is read correctly.  */
+
+static void
+test_loading_repeat ()
+{
+  rtl_dump_test t (SELFTEST_LOCATION, locate_file ("repeat.rtl"));
+
+  rtx_insn *insn_1 = get_insn_by_uid (1);
+  ASSERT_EQ (PARALLEL, GET_CODE (PATTERN (insn_1)));
+  ASSERT_EQ (64, XVECLEN (PATTERN (insn_1), 0));
+  for (int i = 0; i < 64; i++)
+    ASSERT_EQ (const0_rtx, XVECEXP (PATTERN (insn_1), 0, i));
+}
+
 /* Run all of the selftests within this file.  */
 
 void
@@ -2187,6 +2201,7 @@ read_rtl_function_c_tests ()
   test_loading_cfg ();
   test_loading_bb_index ();
   test_loading_mem ();
+  test_loading_repeat ();
 }
 
 } // namespace selftest
diff --git a/gcc/read-rtl.c b/gcc/read-rtl.c
index 723c3e1..d698dd4 100644
--- a/gcc/read-rtl.c
+++ b/gcc/read-rtl.c
@@ -1690,6 +1690,7 @@ rtx_reader::read_rtx_operand (rtx return_rtx, int idx)
 	struct obstack vector_stack;
 	int list_counter = 0;
 	rtvec return_vec = NULL_RTVEC;
+	rtx saved_rtx = NULL_RTX;
 
 	require_char_ws ('[');
 
@@ -1700,8 +1701,34 @@ rtx_reader::read_rtx_operand (rtx return_rtx, int idx)
 	    if (c == EOF)
 	      fatal_expected_char (']', c);
 	    unread_char (c);
-	    list_counter++;
-	    obstack_ptr_grow (&vector_stack, read_nested_rtx ());
+
+	    rtx value;
+	    int repeat_count = 1;
+	    if (c == 'r')
+	      {
+		/* Process "repeated xN" directive.  */
+		read_name (&name);
+		if (strcmp (name.string, "repeated"))
+		  fatal_with_file_and_line ("invalid directive \"%s\"\n",
+					    name.string);
+		read_name (&name);
+		if (!sscanf (name.string, "x%d", &repeat_count))
+		  fatal_with_file_and_line ("invalid repeat count \"%s\"\n",
+					    name.string);
+
+		/* We already saw one of the instances.  */
+		repeat_count--;
+		value = saved_rtx;
+	      }
+	    else
+	      value = read_nested_rtx ();
+
+	    for (; repeat_count > 0; repeat_count--)
+	      {
+		list_counter++;
+		obstack_ptr_grow (&vector_stack, value);
+	      }
+	    saved_rtx = value;
 	  }
 	if (list_counter > 0)
 	  {
diff --git a/gcc/rtl-tests.c b/gcc/rtl-tests.c
index f67f2a3..c684f8e 100644
--- a/gcc/rtl-tests.c
+++ b/gcc/rtl-tests.c
@@ -284,6 +284,29 @@ const_poly_int_tests<N>::run ()
 	     gen_int_mode (poly_int64 (5, -1), QImode));
 }
 
+/* Check dumping of repeated RTL vectors.  */
+
+static void
+test_dumping_repeat ()
+{
+  rtx p = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (3));
+  XVECEXP (p, 0, 0) = const0_rtx;
+  XVECEXP (p, 0, 1) = const0_rtx;
+  XVECEXP (p, 0, 2) = const0_rtx;
+  ASSERT_RTL_DUMP_EQ ("(parallel [\n"
+		      "        (const_int 0) repeated x3\n"
+		      "    ])",
+		      p);
+
+  XVECEXP (p, 0, 1) = const1_rtx;
+  ASSERT_RTL_DUMP_EQ ("(parallel [\n"
+		      "        (const_int 0)\n"
+		      "        (const_int 1)\n"
+		      "        (const_int 0)\n"
+		      "    ])",
+		      p);
+}
+
 /* Run all of the selftests within this file.  */
 
 void
@@ -295,6 +318,7 @@ rtl_tests_c_tests ()
   test_single_set ();
   test_uncond_jump ();
   const_poly_int_tests<NUM_POLY_INT_COEFFS>::run ();
+  test_dumping_repeat ();
 
   /* Purge state.  */
   set_first_insn (NULL);
diff --git a/gcc/testsuite/selftests/repeat.rtl b/gcc/testsuite/selftests/repeat.rtl
new file mode 100644
index 0000000..5507d33
--- /dev/null
+++ b/gcc/testsuite/selftests/repeat.rtl
@@ -0,0 +1,11 @@
+(function "repeat_examples"
+  (insn-chain
+    (block 2
+      (edge-from entry (flags "FALLTHRU"))
+      (cinsn 1
+        (parallel [(const_int 0) repeated x64])
+        "test.c":2 (nil))
+      (edge-to exit (flags "FALLTHRU"))
+    ) ;; block 2
+  ) ;; insn-chain
+) ;; function