'Retpoline' mitigation technique for Spectre (branch target injection)
[CVE-2017-5715]:

https://security.googleblog.com/2018/01/more-details-about-mitigations-for-cpu_4.html
https://support.google.com/faqs/answer/7625886
https://spectreattack.com/
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5715

Patch copied from the 'retpoline-regnames' branch of upstream source repository
(please keep an eye for new branches or updates for existing branches):

http://git.infradead.org/users/dwmw2/gcc-retpoline.git

From c26d2b96599ebc9ff24c685a2dc3b01709aa3cce Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw2@infradead.org>
Date: Sun, 14 Jan 2018 21:27:35 +0000
Subject: [PATCH 09/10] Change %V to bare reg names

---
 gcc/config/i386/i386.c                                    | 2 +-
 gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 318a71840c9..6d345031a82 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -18029,7 +18029,7 @@ print_reg (rtx x, int code, FILE *file)
 	warning (0, "unsupported size for integer register");
       /* FALLTHRU */
     case 4:
-      if (LEGACY_INT_REGNO_P (regno))
+      if (LEGACY_INT_REGNO_P (regno) && code != 'V')
 	putc (msize > 4 && TARGET_64BIT ? 'r' : 'e', file);
       /* FALLTHRU */
     case 2:
diff --git a/gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c b/gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c
index f0cd9b75be8..6791890944c 100644
--- a/gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c
+++ b/gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c
@@ -9,5 +9,5 @@ foo (void)
   asm("call __x86_indirect_thunk_%V0" : : "a" (func_p));
 }
 
-/* { dg-final { scan-assembler "call\[ \t\]*__x86_indirect_thunk_eax" { target ia32 } } } */
-/* { dg-final { scan-assembler "call\[ \t\]*__x86_indirect_thunk_rax" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "call\[ \t\]*__x86_indirect_thunk_ax" { target ia32 } } } */
+/* { dg-final { scan-assembler "call\[ \t\]*__x86_indirect_thunk_ax" { target { ! ia32 } } } } */
-- 
2.15.1