From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 3 Jan 2014 12:22:17 +0000 (+0100)
Subject: re PR target/59625 (asm goto and TARGET_FOUR_JUMP_LIMIT)
X-Git-Tag: releases/gcc-4.9.0~1846
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3bcdbd50ba73bc366027844bcb44ef1afac6e766;p=thirdparty%2Fgcc.git

re PR target/59625 (asm goto and TARGET_FOUR_JUMP_LIMIT)

	PR target/59625
	* config/i386/i386.c (ix86_avoid_jump_mispredicts): Don't consider
	asm goto as jump.

	* gcc.target/i386/pr59625.c: New test.

From-SVN: r206314
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e4d71d700e90..09639d3cd566 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,9 @@
 2014-01-03  Jakub Jelinek  <jakub@redhat.com>
 
+	PR target/59625
+	* config/i386/i386.c (ix86_avoid_jump_mispredicts): Don't consider
+	asm goto as jump.
+
 	* config/i386/i386.md (MODE_SIZE): New mode attribute.
 	(push splitter): Use <P:MODE_SIZE> instead of
 	GET_MODE_SIZE (<P:MODE>mode).
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 637ea655d507..d2f5b6e9fda7 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -38825,7 +38825,10 @@ ix86_avoid_jump_mispredicts (void)
      The smallest offset in the page INSN can start is the case where START
      ends on the offset 0.  Offset of INSN is then NBYTES - sizeof (INSN).
      We add p2align to 16byte window with maxskip 15 - NBYTES + sizeof (INSN).
-     */
+
+     Don't consider asm goto as jump, while it can contain a jump, it doesn't
+     have to, control transfer to label(s) can be performed through other
+     means, and also we estimate minimum length of all asm stmts as 0.  */
   for (insn = start; insn; insn = NEXT_INSN (insn))
     {
       int min_size;
@@ -38852,7 +38855,8 @@ ix86_avoid_jump_mispredicts (void)
 	      while (nbytes + max_skip >= 16)
 		{
 		  start = NEXT_INSN (start);
-		  if (JUMP_P (start) || CALL_P (start))
+		  if ((JUMP_P (start) && asm_noperands (PATTERN (start)) < 0)
+		      || CALL_P (start))
 		    njumps--, isjump = 1;
 		  else
 		    isjump = 0;
@@ -38867,7 +38871,8 @@ ix86_avoid_jump_mispredicts (void)
       if (dump_file)
 	fprintf (dump_file, "Insn %i estimated to %i bytes\n",
 		 INSN_UID (insn), min_size);
-      if (JUMP_P (insn) || CALL_P (insn))
+      if ((JUMP_P (insn) && asm_noperands (PATTERN (insn)) < 0)
+	  || CALL_P (insn))
 	njumps++;
       else
 	continue;
@@ -38875,7 +38880,8 @@ ix86_avoid_jump_mispredicts (void)
       while (njumps > 3)
 	{
 	  start = NEXT_INSN (start);
-	  if (JUMP_P (start) || CALL_P (start))
+	  if ((JUMP_P (start) && asm_noperands (PATTERN (start)) < 0)
+	      || CALL_P (start))
 	    njumps--, isjump = 1;
 	  else
 	    isjump = 0;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0950914255ef..49b55f8b49ec 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-01-03  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/59625
+	* gcc.target/i386/pr59625.c: New test.
+
 2014-01-03  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	Core DR 1442
diff --git a/gcc/testsuite/gcc.target/i386/pr59625.c b/gcc/testsuite/gcc.target/i386/pr59625.c
new file mode 100644
index 000000000000..8e1a7794bc48
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr59625.c
@@ -0,0 +1,36 @@
+/* PR target/59625 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mtune=atom" } */
+
+int
+foo (void)
+{
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  asm goto ("" : : : : lab);
+  return 0;
+lab:
+  return 1;
+}
+
+/* Verify we don't consider asm goto as a jump for four jumps limit
+   optimization.  asm goto doesn't have to contain a jump at all,
+   the branching to labels can happen through different means.  */
+/* { dg-final { scan-assembler-not "(p2align\[^\n\r\]*\[\n\r]*\[^\n\r\]*){8}p2align" } } */