On Mon, Sep 5, 2016 at 7:14 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> As the testcase shows, if we want to diagnose a md builtin not enabled in
> the current ISA, we call error and then return const0_rtx. That isn't a
> good choice if the result is BLKmode, which can happen for vector modes
> that aren't enabled in the current ISA. In that case, returning target
> is better. In the PR I've also mentioned DECL_MODE issues, but looking at
> expr.c, I see there:
> /* DECL_MODE might change when TYPE_MODE depends on attribute target
> settings for VECTOR_TYPE_P that might switch for the function. */
> if (currently_expanding_to_rtl
> && code == VAR_DECL && MEM_P (decl_rtl)
> && VECTOR_TYPE_P (type) && exp && DECL_MODE (exp) != mode)
> decl_rtl = change_address (decl_rtl, TYPE_MODE (type), 0);
> else
> decl_rtl = copy_rtx (decl_rtl);
> so we should be fine.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Hm...
... perhaps we can emit a warning here and expand the builtin as a
call? This way, we will mirror the case when builtin requires some
ISA, e.g.:
void foo ()
{
__builtin_ia32_stmxcsr();
}
$ gcc -S -mno-sse dd.c
dd.c: In function ‘foo’:
dd.c:3:3: warning: implicit declaration of function
‘__builtin_ia32_stmxcsr’ [-Wimplicit-function-declaration]
__builtin_ia32_stmxcsr();
^~~~~~~~~~~~~~~~~~~~~~
Uros.
> 2016-09-05 Jakub Jelinek <ja...@redhat.com>
>
> PR target/69255
> * config/i386/i386.c (ix86_expand_builtin): For builtin with
> unsupported or unknown ISA, return target if non-NULL, instead of
> const0_rtx.
>
> * gcc.target/i386/pr69255-1.c: New test.
> * gcc.target/i386/pr69255-2.c: New test.
> * gcc.target/i386/pr69255-3.c: New test.
>
> --- gcc/config/i386/i386.c.jj 2016-09-02 18:18:10.000000000 +0200
> +++ gcc/config/i386/i386.c 2016-09-05 12:41:03.341382125 +0200
> @@ -36107,7 +36107,7 @@ ix86_expand_builtin (tree exp, rtx targe
> error ("%qE needs isa option %s", fndecl, opts);
> free (opts);
> }
> - return const0_rtx;
> + return target ? target : const0_rtx;
> }
>
> switch (fcode)
> --- gcc/testsuite/gcc.target/i386/pr69255-1.c.jj 2016-09-05
> 12:50:29.455307440 +0200
> +++ gcc/testsuite/gcc.target/i386/pr69255-1.c 2016-09-05 12:50:06.000000000
> +0200
> @@ -0,0 +1,16 @@
> +/* PR target/69255 */
> +/* { dg-do compile } */
> +/* { dg-options "-mno-avx512f" } */
> +
> +#pragma GCC target "avx512vl"
> +#pragma GCC target "no-avx512vl"
> +__attribute__ ((__vector_size__ (32))) long long a;
> +__attribute__ ((__vector_size__ (16))) int b;
> +
> +void
> +foo (const long long *p)
> +{
> + a = __builtin_ia32_gather3siv4di (a, p, b, 1, 1); /* { dg-error "needs
> isa option -m32 -mavx512vl" } */
> +}
> +
> +/* { dg-warning "AVX vector return without AVX enabled changes the ABI" "" {
> target *-*-* } 13 } */
> --- gcc/testsuite/gcc.target/i386/pr69255-2.c.jj 2016-09-05
> 12:50:32.931264038 +0200
> +++ gcc/testsuite/gcc.target/i386/pr69255-2.c 2016-09-05 12:49:57.000000000
> +0200
> @@ -0,0 +1,14 @@
> +/* PR target/69255 */
> +/* { dg-do compile } */
> +/* { dg-options "-mno-avx512f" } */
> +
> +#pragma GCC target "avx512vl"
> +#pragma GCC target ""
> +__attribute__ ((__vector_size__ (32))) long long a;
> +__attribute__ ((__vector_size__ (16))) int b;
> +
> +void
> +foo (const long long *p)
> +{
> + __builtin_ia32_gather3siv4di (a, p, b, 1, 1); /* { dg-error
> "needs isa option -m32 -mavx512vl" } */
> +}
> --- gcc/testsuite/gcc.target/i386/pr69255-3.c.jj 2016-09-05
> 12:50:35.951226330 +0200
> +++ gcc/testsuite/gcc.target/i386/pr69255-3.c 2016-09-05 12:49:13.000000000
> +0200
> @@ -0,0 +1,16 @@
> +/* PR target/69255 */
> +/* { dg-do compile } */
> +/* { dg-options "-mno-avx512f" } */
> +
> +#pragma GCC target "avx512vl"
> +#pragma GCC target ""
> +__attribute__ ((__vector_size__ (32))) long long a;
> +__attribute__ ((__vector_size__ (16))) int b;
> +
> +void
> +foo (const long long *p, __attribute__ ((__vector_size__ (32))) long long *q)
> +{
> + *q = __builtin_ia32_gather3siv4di (a, p, b, 1, 1); /* { dg-error "needs
> isa option -m32 -mavx512vl" } */
> +}
> +
> +/* { dg-warning "AVX vector return without AVX enabled changes the ABI" "" {
> target *-*-* } 13 } */
>
> Jakub
