> -----Original Message-----
> From: Uros Bizjak <ubiz...@gmail.com>
> Sent: Wednesday, June 18, 2025 9:22 PM
> To: Cui, Lili <lili....@intel.com>
> Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao <hongtao....@intel.com>;
> hongjiu...@intel.com
> Subject: Re: [PATCH] x86: Fix shrink wrap separate ICE under -fstack-clash-
> protection [PR120697]
>
> On Wed, Jun 18, 2025 at 3:11 PM Cui, Lili <lili....@intel.com> wrote:
> >
> > From: Lili Cui <lili....@intel.com>
> >
> > Hi Uros,
> >
> > An assertion I added in shrink wrap separate V2 reports ICE when -fstack-
> clash-protection is enabled. The assertion should not be added here.
> >
> > I created a patch to remove 3 assertions and their associated code.
> >
> > 1. Reproduced PR120697 issue and solved the issue with this patch, also
> added a new test case for -fstack-clash-protection.
> > 2. Recollected performance data with -fstack-clash-protection, there is no
> ICE and regressions.
> > 3. Use this patch to build the latest Linux kernel and boot successfully.
> > 4. Bootstrapped & regtested on x86-64-pc-linux-gnu.
> >
> > Ok for master?
> >
> > Thanks,
> > Lili.
> >
> >
> > gcc/ChangeLog:
> >
> > PR target/120697
> > * config/i386/i386.cc (ix86_expand_prologue):
> > Remove 3 assertions and associated code.
> >
> > gcc/testsuite/ChangeLog:
> >
> > PR target/120697
> > * gcc.target/i386/stack-clash-protection.c: New test.
>
> LGTM, but only in the sense that you are reverting parts of the original
> patch.
>
Sure, this fix simply removes some code in shrink-wrapped separate patch. Once
Sam has verified the patch in his environment, I will commit the patch.
Thanks,
Lili.
> Thanks,
> Uros.
>
> > ---
> > gcc/config/i386/i386.cc | 14 +-------------
> > .../gcc.target/i386/stack-clash-protection.c | 19
> > +++++++++++++++++++
> > 2 files changed, 20 insertions(+), 13 deletions(-) create mode
> > 100644 gcc/testsuite/gcc.target/i386/stack-clash-protection.c
> >
> > diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc index
> > 3824b533989..6dce7cdfdcb 100644
> > --- a/gcc/config/i386/i386.cc
> > +++ b/gcc/config/i386/i386.cc
> > @@ -9234,10 +9234,9 @@ ix86_expand_prologue (void)
> > the stack frame saving one cycle of the prologue. However, avoid
> > doing this if we have to probe the stack; at least on x86_64 the
> > stack probe can turn into a call that clobbers a red zone
> > location. */
> > - else if ((ix86_using_red_zone ()
> > + else if (ix86_using_red_zone ()
> > && (! TARGET_STACK_PROBE
> > || frame.stack_pointer_offset < CHECK_STACK_LIMIT))
> > - || crtl->shrink_wrapped_separate)
> > {
> > HOST_WIDE_INT allocate_offset;
> > if (crtl->shrink_wrapped_separate) @@ -9253,11 +9252,6 @@
> > ix86_expand_prologue (void)
> >
> > ix86_emit_save_regs_using_mov (frame.reg_save_offset);
> > int_registers_saved = true;
> > -
> > - if (ix86_using_red_zone ()
> > - && (! TARGET_STACK_PROBE
> > - || frame.stack_pointer_offset < CHECK_STACK_LIMIT))
> > - cfun->machine->red_zone_used = true;
> > }
> > }
> >
> > @@ -9377,8 +9371,6 @@ ix86_expand_prologue (void)
> > && flag_stack_clash_protection
> > && !ix86_target_stack_probe ())
> > {
> > - gcc_assert (!crtl->shrink_wrapped_separate);
> > -
> > ix86_adjust_stack_and_probe (allocate, int_registers_saved, false);
> > allocate = 0;
> > }
> > @@ -9389,8 +9381,6 @@ ix86_expand_prologue (void)
> > {
> > const HOST_WIDE_INT probe_interval = get_probe_interval ();
> >
> > - gcc_assert (!crtl->shrink_wrapped_separate);
> > -
> > if (STACK_CHECK_MOVING_SP)
> > {
> > if (crtl->is_leaf
> > @@ -9447,8 +9437,6 @@ ix86_expand_prologue (void)
> > else if (!ix86_target_stack_probe ()
> > || frame.stack_pointer_offset < CHECK_STACK_LIMIT)
> > {
> > - gcc_assert (!crtl->shrink_wrapped_separate);
> > -
> > pro_epilogue_adjust_stack (stack_pointer_rtx, stack_pointer_rtx,
> > GEN_INT (-allocate), -1,
> > m->fs.cfa_reg == stack_pointer_rtx);
> > diff --git a/gcc/testsuite/gcc.target/i386/stack-clash-protection.c
> > b/gcc/testsuite/gcc.target/i386/stack-clash-protection.c
> > new file mode 100644
> > index 00000000000..5be28cb3ac7
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/stack-clash-protection.c
> > @@ -0,0 +1,19 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -fstack-clash-protection" } */
> > +
> > +int flag;
> > +void open();
> > +int getChar();
> > +typedef enum { QUOTE } CharType;
> > +typedef enum { UNQ } State;
> > +CharType getCharType();
> > +void expand() {
> > + open();
> > + if (flag)
> > + return;
> > + int ch = getChar();
> > + State nextState = getCharType();
> > + if (nextState)
> > + while (ch)
> > + ;
> > +}
> > --
> > 2.34.1
> >
