[Bug target/88717] Unnecessary vzeroupper

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88717

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |9.0

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> ---
Like this

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index d01278d866f..9b49a2c1d9c 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -19100,7 +19100,11 @@ ix86_avx_u128_mode_entry (void)
       rtx incoming = DECL_INCOMING_RTL (arg);

       if (incoming && ix86_check_avx_upper_register (incoming))
-       return AVX_U128_DIRTY;
+       {
+         /* Caller is AVX_U128_DIRTY.  */
+         cfun->machine->caller_avx_u128_dirty = true;
+         return AVX_U128_DIRTY;
+       }
     }

   return AVX_U128_CLEAN;
@@ -19130,6 +19134,10 @@ ix86_mode_entry (int entity)
 static int
 ix86_avx_u128_mode_exit (void)
 {
+  /* Exit mode is set to AVX_U128_DIRTY if caller is AVX_U128_DIRTY.  */
+  if (cfun->machine->caller_avx_u128_dirty)
+    return AVX_U128_DIRTY;
+
   rtx reg = crtl->return_rtx;

   /* Exit mode is set to AVX_U128_DIRTY if there are 256bit
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 83b025e0cf5..c053b657a55 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -2747,6 +2747,9 @@ struct GTY(()) machine_function {
   /* If true, ENDBR is queued at function entrance.  */
   BOOL_BITFIELD endbr_queued_at_entrance : 1;

+  /* If true, caller is AVX_U128_DIRTY.  */
+  BOOL_BITFIELD caller_avx_u128_dirty : 1;
+
   /* The largest alignment, in bytes, of stack slot actually used.  */
   unsigned int max_used_stack_alignment;