On Tue, Jan 8, 2019 at 9:29 AM Uros Bizjak <ubiz...@gmail.com> wrote:
>
> On Tue, Jan 8, 2019 at 5:17 PM H.J. Lu <hjl.to...@gmail.com> wrote:
> >
> > On Tue, Jan 8, 2019 at 6:54 AM Uros Bizjak <ubiz...@gmail.com> wrote:
> > >
> > > On Tue, Jan 8, 2019 at 3:39 PM H.J. Lu <hjl.to...@gmail.com> wrote:
> > > >
> > > > On Mon, Jan 7, 2019 at 11:12 PM Uros Bizjak <ubiz...@gmail.com> wrote:
> > > > >
> > > > > On Mon, Jan 7, 2019 at 6:40 PM H.J. Lu <hongjiu...@intel.com> wrote:
> > > > > >
> > > > > > There is no need to generate vzeroupper if caller uses upper bits of
> > > > > > AVX/AVX512 registers, We track caller's avx_u128_state and avoid
> > > > > > vzeroupper when caller's avx_u128_state is AVX_U128_DIRTY.
> > > > > >
> > > > > > Tested on i686 and x86-64 with and without --with-arch=native.
> > > > > >
> > > > > > OK for trunk?
> > > > >
> > > > > In principle OK, but I think we don't have to cache the result of
> > > > > ix86_avx_u128_mode_entry. Simply call the function from
> > > > > ix86_avx_u128_mode_exit; it is a simple function, so I guess we can
> > > > > afford to re-call it one more time per function.
> > > >
> > > > Do we really need ix86_avx_u128_mode_entry? We can just
> > > > set entry state to AVX_U128_CLEAN and set exit state to
> > > > AVX_U128_DIRTY if caller returns AVX/AVX512 register or passes
> > > > AVX/AVX512 registers to callee.
> > > >
> > > > Does this patch look OK?
> > >
> > > No, the compiler is then free to move optimal insertion point at the
> > > beginning of the function.
> > >
> >
> > Here is the updated patch. OK for trunk?
>
> OK with the comment fix.
>
> Thanks,
> Uros.
>
> - return AVX_U128_CLEAN;
> + /* Entry mode is set to AVX_U128_DIRTY if there are 256bit or 512bit
>
> s/Entry/Exit/
>
> + modes used in function arguments. */
>
> ... , otherwise return AVX_U128_CLEAN.
>
> + return ix86_avx_u128_mode_entry ();
> }
This is what I am checking in.
Thanks.
--
H.J.
From 315e6eadf7021748de375c59da9cf451351c9597 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.to...@gmail.com>
Date: Mon, 7 Jan 2019 06:56:44 -0800
Subject: [PATCH] x86: Don't generate vzeroupper if caller passes AVX/AVX512
registers
There is no need to generate vzeroupper if caller passes arguments in
AVX/AVX512 registers.
Tested on i686 and x86-64 with and without --with-arch=native.
gcc/
PR target/88717
* config/i386/i386.c (ix86_avx_u128_mode_exit): Call
ix86_avx_u128_mode_entry.
gcc/testsuite/
PR target/88717
* gcc.target/i386/pr88717.c: New test.
---
gcc/config/i386/i386.c | 5 ++++-
gcc/testsuite/gcc.target/i386/pr88717.c | 24 ++++++++++++++++++++++++
2 files changed, 28 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr88717.c
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index d01278d866f..bd48e080f46 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -19137,7 +19137,10 @@ ix86_avx_u128_mode_exit (void)
if (reg && ix86_check_avx_upper_register (reg))
return AVX_U128_DIRTY;
- return AVX_U128_CLEAN;
+ /* Exit mode is set to AVX_U128_DIRTY if there are 256bit or 512bit
+ modes used in function arguments, otherwise return AVX_U128_CLEAN.
+ */
+ return ix86_avx_u128_mode_entry ();
}
/* Return a mode that ENTITY is assumed to be
diff --git a/gcc/testsuite/gcc.target/i386/pr88717.c b/gcc/testsuite/gcc.target/i386/pr88717.c
new file mode 100644
index 00000000000..01680998f1b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr88717.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mavx512f -mvzeroupper" } */
+
+#include <immintrin.h>
+
+__m128
+foo1 (__m256 x)
+{
+ return _mm256_castps256_ps128 (x);
+}
+
+void
+foo2 (float *p, __m256 x)
+{
+ *p = ((__v8sf)x)[0];
+}
+
+void
+foo3 (float *p, __m512 x)
+{
+ *p = ((__v16sf)x)[0];
+}
+
+/* { dg-final { scan-assembler-not "vzeroupper" } } */
--
2.20.1
