[x86_64,take,#2] PR target/106450: Tweak timode_remove_non_convertible_regs.
Commit Message
Many thanks to H.J. for pointing out a better idiom for traversing
the USEs (and also DEFs) of TImode registers in an instruction.
This revised patched has been tested on x86_64-pc-linux-gnu with
make bootstrap and make -k check, both with and without
--target_board=unix{-m32}, with no new failures. Ok for mainline?
2022-07-30 Roger Sayle <roger@nextmovesoftware.com>
H.J. Lu <hjl.tools@gmail.com>
gcc/ChangeLog
PR target/106450
* config/i386/i386-features.cc (timode_check_non_convertible_regs):
Do nothing if REGNO is set in the REGS bitmap, or is a hard reg.
(timode_remove_non_convertible_regs): Update comment.
Call timode_check_non_convertible_reg on all TImode register
DEFs and USEs in each instruction.
gcc/testsuite/ChangeLog
PR target/106450
* gcc.target/i386/pr106450.c: New test case.
Thanks (H.J. and Uros),
Roger
--
> -----Original Message-----
> From: H.J. Lu <hjl.tools@gmail.com>
> Sent: 28 July 2022 17:55
> To: Roger Sayle <roger@nextmovesoftware.com>
> Cc: GCC Patches <gcc-patches@gcc.gnu.org>
> Subject: Re: [x86_64 PATCH] PR target/106450: Tweak
> timode_remove_non_convertible_regs.
>
> On Thu, Jul 28, 2022 at 9:43 AM Roger Sayle <roger@nextmovesoftware.com>
> wrote:
> >
> > This patch resolves PR target/106450, some more fall-out from more
> > aggressive TImode scalar-to-vector (STV) optimizations. I continue to
> > be caught out by how far TImode STV has diverged from DImode/SImode
> > STV, and therefore requires additional (unexpected) tweaking. Many
> > thanks to H.J. Lu for pointing out timode_remove_non_convertible_regs
> > needs to be extended to handle XOR (and other new operations).
> >
> > Unhelpfully the comment above this function states that it's the
> > TImode version of "remove_non_convertible_regs", which doesn't exist
> > anymore, so I've resurrected an explanatory comment from the git history.
> > By refactoring the checks for hard regs and already "marked" regs into
> > timode_check_non_convertible_regs itself, all its callers are
> > simplified. This patch then uses GET_RTX_CLASS to generically handle
> > unary and binary operations, calling timode_check_non_convertible_regs
> > on each TImode register operand in the single_set's SET_SRC.
> >
> > This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
> > and make -k check, both with and without --target_board=unix{-m32},
> > with no new failures. Ok for mainline?
> >
> >
> > 2022-07-28 Roger Sayle <roger@nextmovesoftware.com>
> >
> > gcc/ChangeLog
> > PR target/106450
> > * config/i386/i386-features.cc (timode_check_non_convertible_regs):
> > Do nothing if REGNO is set in the REGS bitmap, or is a hard reg.
> > (timode_remove_non_convertible_regs): Update comment.
> > Call timode_check_non_convertible_regs on all register operands
> > of supported (binary and unary) operations.
>
> Should we use
>
> df_ref ref;
> FOR_EACH_INSN_USE (ref, insn)
> if (!DF_REF_REG_MEM_P (ref))
> timode_check_non_convertible_regs (candidates, regs,
> DF_REF_REGNO (ref));
>
> to check each use?
>
> > gcc/testsuite/ChangeLog
> > PR target/106450
> > * gcc.target/i386/pr106450.c: New test case.
> >
> >
> > Thanks in advance,
> > Roger
> > --
> --
> H.J.
Comments
On Sat, Jul 30, 2022 at 11:42 AM Roger Sayle <roger@nextmovesoftware.com> wrote:
>
>
> Many thanks to H.J. for pointing out a better idiom for traversing
> the USEs (and also DEFs) of TImode registers in an instruction.
>
> This revised patched has been tested on x86_64-pc-linux-gnu with
> make bootstrap and make -k check, both with and without
> --target_board=unix{-m32}, with no new failures. Ok for mainline?
>
>
> 2022-07-30 Roger Sayle <roger@nextmovesoftware.com>
> H.J. Lu <hjl.tools@gmail.com>
>
> gcc/ChangeLog
> PR target/106450
> * config/i386/i386-features.cc (timode_check_non_convertible_regs):
> Do nothing if REGNO is set in the REGS bitmap, or is a hard reg.
> (timode_remove_non_convertible_regs): Update comment.
> Call timode_check_non_convertible_reg on all TImode register
> DEFs and USEs in each instruction.
>
> gcc/testsuite/ChangeLog
> PR target/106450
> * gcc.target/i386/pr106450.c: New test case.
LGTM.
Thanks,
Uros.
>
>
> Thanks (H.J. and Uros),
> Roger
> --
>
> > -----Original Message-----
> > From: H.J. Lu <hjl.tools@gmail.com>
> > Sent: 28 July 2022 17:55
> > To: Roger Sayle <roger@nextmovesoftware.com>
> > Cc: GCC Patches <gcc-patches@gcc.gnu.org>
> > Subject: Re: [x86_64 PATCH] PR target/106450: Tweak
> > timode_remove_non_convertible_regs.
> >
> > On Thu, Jul 28, 2022 at 9:43 AM Roger Sayle <roger@nextmovesoftware.com>
> > wrote:
> > >
> > > This patch resolves PR target/106450, some more fall-out from more
> > > aggressive TImode scalar-to-vector (STV) optimizations. I continue to
> > > be caught out by how far TImode STV has diverged from DImode/SImode
> > > STV, and therefore requires additional (unexpected) tweaking. Many
> > > thanks to H.J. Lu for pointing out timode_remove_non_convertible_regs
> > > needs to be extended to handle XOR (and other new operations).
> > >
> > > Unhelpfully the comment above this function states that it's the
> > > TImode version of "remove_non_convertible_regs", which doesn't exist
> > > anymore, so I've resurrected an explanatory comment from the git history.
> > > By refactoring the checks for hard regs and already "marked" regs into
> > > timode_check_non_convertible_regs itself, all its callers are
> > > simplified. This patch then uses GET_RTX_CLASS to generically handle
> > > unary and binary operations, calling timode_check_non_convertible_regs
> > > on each TImode register operand in the single_set's SET_SRC.
> > >
> > > This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
> > > and make -k check, both with and without --target_board=unix{-m32},
> > > with no new failures. Ok for mainline?
> > >
> > >
> > > 2022-07-28 Roger Sayle <roger@nextmovesoftware.com>
> > >
> > > gcc/ChangeLog
> > > PR target/106450
> > > * config/i386/i386-features.cc (timode_check_non_convertible_regs):
> > > Do nothing if REGNO is set in the REGS bitmap, or is a hard reg.
> > > (timode_remove_non_convertible_regs): Update comment.
> > > Call timode_check_non_convertible_regs on all register operands
> > > of supported (binary and unary) operations.
> >
> > Should we use
> >
> > df_ref ref;
> > FOR_EACH_INSN_USE (ref, insn)
> > if (!DF_REF_REG_MEM_P (ref))
> > timode_check_non_convertible_regs (candidates, regs,
> > DF_REF_REGNO (ref));
> >
> > to check each use?
> >
> > > gcc/testsuite/ChangeLog
> > > PR target/106450
> > > * gcc.target/i386/pr106450.c: New test case.
> > >
> > >
> > > Thanks in advance,
> > > Roger
> > > --
> > --
> > H.J.
@@ -1808,6 +1808,11 @@ static void
timode_check_non_convertible_regs (bitmap candidates, bitmap regs,
unsigned int regno)
{
+ /* Do nothing if REGNO is already in REGS or is a hard reg. */
+ if (bitmap_bit_p (regs, regno)
+ || HARD_REGISTER_NUM_P (regno))
+ return;
+
for (df_ref def = DF_REG_DEF_CHAIN (regno);
def;
def = DF_REF_NEXT_REG (def))
@@ -1843,7 +1848,13 @@ timode_check_non_convertible_regs (bitmap candidates, bitmap regs,
}
}
-/* The TImode version of remove_non_convertible_regs. */
+/* For a given bitmap of insn UIDs scans all instructions and
+ remove insn from CANDIDATES in case it has both convertible
+ and not convertible definitions.
+
+ All insns in a bitmap are conversion candidates according to
+ scalar_to_vector_candidate_p. Currently it implies all insns
+ are single_set. */
static void
timode_remove_non_convertible_regs (bitmap candidates)
@@ -1857,25 +1868,20 @@ timode_remove_non_convertible_regs (bitmap candidates)
changed = false;
EXECUTE_IF_SET_IN_BITMAP (candidates, 0, id, bi)
{
- rtx def_set = single_set (DF_INSN_UID_GET (id)->insn);
- rtx dest = SET_DEST (def_set);
- rtx src = SET_SRC (def_set);
-
- if ((!REG_P (dest)
- || bitmap_bit_p (regs, REGNO (dest))
- || HARD_REGISTER_P (dest))
- && (!REG_P (src)
- || bitmap_bit_p (regs, REGNO (src))
- || HARD_REGISTER_P (src)))
- continue;
-
- if (REG_P (dest))
- timode_check_non_convertible_regs (candidates, regs,
- REGNO (dest));
-
- if (REG_P (src))
- timode_check_non_convertible_regs (candidates, regs,
- REGNO (src));
+ rtx_insn *insn = DF_INSN_UID_GET (id)->insn;
+ df_ref ref;
+
+ FOR_EACH_INSN_DEF (ref, insn)
+ if (!DF_REF_REG_MEM_P (ref)
+ && GET_MODE (DF_REF_REG (ref)) == TImode)
+ timode_check_non_convertible_regs (candidates, regs,
+ DF_REF_REGNO (ref));
+
+ FOR_EACH_INSN_USE (ref, insn)
+ if (!DF_REF_REG_MEM_P (ref)
+ && GET_MODE (DF_REF_REG (ref)) == TImode)
+ timode_check_non_convertible_regs (candidates, regs,
+ DF_REF_REGNO (ref));
}
EXECUTE_IF_SET_IN_BITMAP (regs, 0, id, bi)
new file mode 100644
@@ -0,0 +1,14 @@
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -fsplit-paths" } */
+
+__int128 n;
+
+__attribute__ ((simd)) void
+foo (void)
+{
+ __int128 uninitialized;
+ unsigned __int128 *p = &n;
+
+ n >>= *p ? : 2;
+ n |= uninitialized;
+}