| Message ID | orzhjz4uov.fsf@lxoliva.fsfla.org |
|---|---|
| State | New |
| Headers | show |
| Series | [x86,testsuite] preserve full register across main | expand |
On Friday, August 23, 2019, Alexandre Oliva <oliva@adacore.com> wrote: > 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; Can __attribute__ ((mode (__word__))) be used here? Otherwise OK. Thanks, Uros. > #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 >
On Aug 24, 2019, Uros Bizjak <ubizjak@gmail.com> wrote: > Can __attribute__ ((mode (__word__))) be used here? Oh, nice, yes, thanks! > Otherwise OK. Here's what I'm installing. 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 5641826b4837c..48dea27956ce2 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 int __attribute__ ((mode (__word__))) 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;
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;