[PATCH] x86: Fix shrink wrap separate ICE under -fstack-clash-protection [PR120697]

[Cui, Lili]

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.
---
 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