File gcc48-backport-pr86952-jump-tables.patch of Package gcc48

From c3aaec679c56a079c7faf66500db039c358516cc Mon Sep 17 00:00:00 2001
From: marxin <marxin@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 8 Mar 2019 12:55:40 +0000
Subject: [PATCH] Backport r269492

gcc/ChangeLog:

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.

gcc/testsuite/ChangeLog:

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.
---
 gcc/config/i386/i386.c                        |  6 +++++
 .../gcc.target/i386/indirect-thunk-7.c        |  2 +-
 .../gcc.target/i386/indirect-thunk-extern-7.c |  2 +-
 .../gcc.target/i386/indirect-thunk-inline-7.c |  2 +-
 gcc/testsuite/gcc.target/i386/pr86952.c       | 23 +++++++++++++++++++
 5 files changed, 32 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr86952.c

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index ed1f81fd7b0..afa7feb670d 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -3856,6 +3856,12 @@ ix86_option_override_internal (bool main_args_p)
   if (main_args_p)
     target_option_default_node = target_option_current_node
       = build_target_option_node ();
+
+  /* PR86952: jump table usage with retpolines is slow.
+     The PR provides some numbers about the slowness.  */
+  if (ix86_indirect_branch != indirect_branch_keep
+      && !global_options_set.x_flag_jump_tables)
+    flag_jump_tables = 0;
 }
 
 /* Implement the TARGET_OPTION_OVERRIDE hook.  */
diff --git a/gcc/testsuite/gcc.target/i386/indirect-thunk-7.c b/gcc/testsuite/gcc.target/i386/indirect-thunk-7.c
index 17c2d0faf88..cc5b831114d 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 aece9383697..47a36c9bdb6 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 c67066cf197..61eac23fd31 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 00000000000..004e167add0
--- /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\[ \t\]\\*" } } */
-- 
2.21.0