From: Martin Liska <mliska@suse.cz>
Date: Thu, 11 Apr 2019 08:59:48 +0000 (+0200)
Subject: Backport r269492
X-Git-Tag: releases/gcc-7.5.0~489
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=15dc6451c6446888dc45c0a4a622ea5bf9210d9c;p=thirdparty%2Fgcc.git

Backport r269492

2019-04-11  Martin Liska  <mliska@suse.cz>

	Backport from mainline
	2019-03-08  Martin Liska  <mliska@suse.cz>

	PR target/86952
	* config/i386/i386.c (ix86_option_override_internal): Disable
	jump tables when retpolines are used.
2019-04-11  Martin Liska  <mliska@suse.cz>

	Backport from mainline
	2019-03-08  Martin Liska  <mliska@suse.cz>

	PR target/86952
	* gcc.target/i386/pr86952.c: New test.
	* gcc.target/i386/indirect-thunk-7.c: Use jump tables to match
	scanned pattern.
	* gcc.target/i386/indirect-thunk-inline-7.c: Likewise.

From-SVN: r270277
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 00910dcf3755..c0b8b5bc9998 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2019-04-11  Martin Liska  <mliska@suse.cz>
+
+	Backport from mainline
+	2019-03-08  Martin Liska  <mliska@suse.cz>
+
+	PR target/86952
+	* config/i386/i386.c (ix86_option_override_internal): Disable
+	jump tables when retpolines are used.
+
 2019-04-10  Matthew Malcomson  <matthew.malcomson@arm.com>
 
 	PR target/90024
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 18dce38640b5..96bdb3a78ba9 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6282,6 +6282,12 @@ ix86_option_override_internal (bool main_args_p,
     target_option_default_node = target_option_current_node
       = build_target_option_node (opts);
 
+  /* PR86952: jump table usage with retpolines is slow.
+     The PR provides some numbers about the slowness.  */
+  if (ix86_indirect_branch != indirect_branch_keep
+      && !opts_set->x_flag_jump_tables)
+    opts->x_flag_jump_tables = 0;
+
   return true;
 }
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d235ad826e6b..3e4395151c1d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,14 @@
+2019-04-11  Martin Liska  <mliska@suse.cz>
+
+	Backport from mainline
+	2019-03-08  Martin Liska  <mliska@suse.cz>
+
+	PR target/86952
+	* gcc.target/i386/pr86952.c: New test.
+	* gcc.target/i386/indirect-thunk-7.c: Use jump tables to match
+	scanned pattern.
+	* gcc.target/i386/indirect-thunk-inline-7.c: Likewise.
+
 2019-04-10  Harald Anlauf  <anlauf@gmx.de>
 
 	Backport from trunk
diff --git a/gcc/testsuite/gcc.target/i386/indirect-thunk-7.c b/gcc/testsuite/gcc.target/i386/indirect-thunk-7.c
index 3c72036dbaf4..53868f46558d 100644
--- a/gcc/testsuite/gcc.target/i386/indirect-thunk-7.c
+++ b/gcc/testsuite/gcc.target/i386/indirect-thunk-7.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -mno-indirect-branch-register -mfunction-return=keep -mindirect-branch=thunk -fno-pic" } */
+/* { dg-options "-O2 -mno-indirect-branch-register -mfunction-return=keep -mindirect-branch=thunk -fno-pic -fjump-tables" } */
 
 void func0 (void);
 void func1 (void);
diff --git a/gcc/testsuite/gcc.target/i386/indirect-thunk-extern-7.c b/gcc/testsuite/gcc.target/i386/indirect-thunk-extern-7.c
index 2b9a33e93dca..bc185fe98afe 100644
--- a/gcc/testsuite/gcc.target/i386/indirect-thunk-extern-7.c
+++ b/gcc/testsuite/gcc.target/i386/indirect-thunk-extern-7.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -mno-indirect-branch-register -mfunction-return=keep -mindirect-branch=thunk-extern -fno-pic" } */
+/* { dg-options "-O2 -mno-indirect-branch-register -mfunction-return=keep -mindirect-branch=thunk-extern -fno-pic -fjump-tables" } */
 
 void func0 (void);
 void func1 (void);
diff --git a/gcc/testsuite/gcc.target/i386/indirect-thunk-inline-7.c b/gcc/testsuite/gcc.target/i386/indirect-thunk-inline-7.c
index ea009245a58f..e6f064959a1c 100644
--- a/gcc/testsuite/gcc.target/i386/indirect-thunk-inline-7.c
+++ b/gcc/testsuite/gcc.target/i386/indirect-thunk-inline-7.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -mno-indirect-branch-register -mfunction-return=keep -mindirect-branch=thunk-inline -fno-pic" } */
+/* { dg-options "-O2 -mno-indirect-branch-register -mfunction-return=keep -mindirect-branch=thunk-inline -fno-pic -fjump-tables" } */
 
 void func0 (void);
 void func1 (void);
diff --git a/gcc/testsuite/gcc.target/i386/pr86952.c b/gcc/testsuite/gcc.target/i386/pr86952.c
new file mode 100644
index 000000000000..004e167add0a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr86952.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mindirect-branch=thunk" } */
+
+int global;
+
+int
+foo (int x)
+{
+  switch (x & 7)
+    {
+      case 0: ; return 1722;
+      case 1: global += 1; return 1060;
+      case 2: ; return 1990;
+      case 3: ; return 1242;
+      case 4: ; return 1466;
+      case 5: ; return 894;
+      case 6: ; return 570;
+      case 7: ; return 572;
+      default: return 0;
+    }
+}
+
+/* { dg-final { scan-assembler-not "jmp\[ \t\]\\*" } } */