Re: [PATCH] [i386] Fix _mm256_zeroupper to notify LRA that vzeroupper will kill sse registers. [PR target/82735]

[Hongtao Liu <crazylht@gmail.com>]

On Tue, May 18, 2021 at 11:18 PM Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> Hongtao Liu via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> > On Mon, May 17, 2021 at 5:56 PM Richard Sandiford
> > <richard.sandiford@arm.com> wrote:
> >> It looks like the rtx “used” flag is unused for INSNs, so we could
> >> use that as a CALL_INSN flag that indicates a fake call.  We could just
> >> need to make:
> >>
> >>       /* For all other RTXes clear the used flag on the copy.  */
> >>       RTX_FLAG (copy, used) = 0;
> >>
> >> conditional on !INSN_P.
> >>
> > I got another error in
> >
> > @@ -83,6 +83,9 @@ control_flow_insn_p (const rtx_insn *insn)
> >        return true;
> >
> >      case CALL_INSN:
> > +      /* CALL_INSN use "used" flag to indicate it's a fake call.  */
> > +      if (RTX_FLAG (insn, used))
> > + break;
>
> I guess this is because of the nonlocal_goto condition?  If so, that
> could be fixed by adding a REG_EH_REGION note of INT_MIN.  Even if we
> don't do that, I think the fix belongs in nonlocal_goto instead.
>
This is error info, IMHO, the fix should be in control_flow_insn_p?

../../gcc/gnu-toolchain/pr82735/gcc/testsuite/gcc.target/i386/pr64061.c:
In function ‘foo’:
../../gcc/gnu-toolchain/pr82735/gcc/testsuite/gcc.target/i386/pr64061.c:21:1:
error: in basic block 5:
   21 | }
      | ^
../../gcc/gnu-toolchain/pr82735/gcc/testsuite/gcc.target/i386/pr64061.c:21:1:
error: flow control insn inside a basic block
(call_insn 77 50 86 5 (parallel [
            (call (mem:QI (unspec_volatile [
                            (const_int 0 [0])
                        ] UNSPECV_VZEROUPPER) [0  S1 A8])
                (const_int 0 [0]))
            (unspec [
                    (const_int 1 [0x1])
                ] UNSPEC_CALLEE_ABI)
        ]) -1
     (nil)
    (nil))
during RTL pass: pro_and_epilogue
../../gcc/gnu-toolchain/pr82735/gcc/testsuite/gcc.target/i386/pr64061.c:21:1:
internal compiler error: in rtl_verify_bb_insns, at cfgrtl.c:2797
0x129a2a3 _fatal_insn(char const*, rtx_def const*, char const*, int,
char const*)
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/rtl-error.c:108
0xcb8834 rtl_verify_bb_insns
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/cfgrtl.c:2797
0xcb8b09 rtl_verify_flow_info_1
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/cfgrtl.c:2883
0xcb9284 rtl_verify_flow_info
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/cfgrtl.c:3125
0xc9f44d verify_flow_info()
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/cfghooks.c:267
0xcb21b7 checking_verify_flow_info
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/cfghooks.h:212
0xcb6a3c commit_edge_insertions()
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/cfgrtl.c:2115
0xebfcb8 thread_prologue_and_epilogue_insns()
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/function.c:6136
0xec07db rest_of_handle_thread_prologue_and_epilogue
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/function.c:6510
0xec09b8 execute
/export/users2/liuhongt/gcc/gnu-toolchain/pr82735/gcc/function.c:6586
>
> Thanks,
> Richard



-- 
BR,
Hongtao