[x86 testsuite] preserve full register across main

[Alexandre Oliva <oliva@adacore.com>]

This test uses a call-saved register as a global variable.  It
attempts to preserve its value across main, but only the lower int
part is preserved, which is not good enough for x86_64, when the
runtime that calls main() happens to hold something in the chosen
register that is not a zero-extension from the 32-bit value, and
rightfully expects the full register to remain unchanged when main()
returns.

Tested on x86_64-linux-gnu, both -m64 and -m32.  Ok to install?


for  gcc/testsuite/ChangeLog

	* gcc.target/i386/20020616-1.c: Preserve full register across
	main.
---
 gcc/testsuite/gcc.target/i386/20020616-1.c |   14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/gcc/testsuite/gcc.target/i386/20020616-1.c b/gcc/testsuite/gcc.target/i386/20020616-1.c
index 5641826b4837..3b8cf8e41783 100644
--- a/gcc/testsuite/gcc.target/i386/20020616-1.c
+++ b/gcc/testsuite/gcc.target/i386/20020616-1.c
@@ -2,12 +2,16 @@
 /* { dg-do run } */
 /* { dg-options "-O2" } */
 
+/* We need this type to be as wide as the register chosen below, so
+   that, when we preserve it across main, we preserve all of it.  */
+typedef long reg_type;
+
 #if !__PIC__
-register int k asm("%ebx");
+register reg_type k asm("%ebx");
 #elif __amd64
-register int k asm("%r12");
+register reg_type k asm("%r12");
 #else
-register int k asm("%esi");
+register reg_type k asm("%esi");
 #endif
 
 void __attribute__((noinline))
@@ -18,7 +22,7 @@ foo()
 
 void test()
 {
-  int i;
+  reg_type i;
   for (i = 0; i < 10; i += k)
     {
       k = 0;
@@ -28,7 +32,7 @@ void test()
 
 int main()
 {
-  int old = k;
+  reg_type old = k;
   test();
   k = old;
   return 0;

-- 
Alexandre Oliva, freedom fighter  he/him   https://FSFLA.org/blogs/lxo
Be the change, be Free!                 FSF Latin America board member
GNU Toolchain Engineer                        Free Software Evangelist
Hay que enGNUrecerse, pero sin perder la terGNUra jamás - Che GNUevara