[gcc r14-1508] rtl-optimization: [PR102733] DSE removing address which only differ by address space.

[Andrew Pinski <pinskia@gcc.gnu.org>]

https://gcc.gnu.org/g:64ca6aa74b6b5a9737f3808bf4a947dd5c122d47

commit r14-1508-g64ca6aa74b6b5a9737f3808bf4a947dd5c122d47
Author: Andrew Pinski <apinski@marvell.com>
Date:   Thu Jun 1 21:17:56 2023 -0700

    rtl-optimization: [PR102733] DSE removing address which only differ by address space.
    
    The problem here is DSE was not taking into account the address space
    which meant if you had two addresses say `fs:0` and `gs:0` (on x86_64),
    DSE would think they were the same and remove the first store.
    This fixes that issue by adding a check for the address space too.
    
    OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
    
            PR rtl-optimization/102733
    
    gcc/ChangeLog:
    
            * dse.cc (store_info): Add addrspace field.
            (record_store): Record the address space
            and check to make sure they are the same.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/i386/addr-space-6.c: New test.

Diff:
---
 gcc/dse.cc                                   |  9 ++++++++-
 gcc/testsuite/gcc.target/i386/addr-space-6.c | 21 +++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/gcc/dse.cc b/gcc/dse.cc
index 802b949cfb2..8b07be17674 100644
--- a/gcc/dse.cc
+++ b/gcc/dse.cc
@@ -251,6 +251,9 @@ public:
      and known (rather than -1).  */
   poly_int64 width;
 
+  /* The address space that the memory reference uses.  */
+  unsigned char addrspace;
+
   union
     {
       /* A bitmask as wide as the number of bytes in the word that
@@ -1524,6 +1527,7 @@ record_store (rtx body, bb_info_t bb_info)
   ptr = active_local_stores;
   last = NULL;
   redundant_reason = NULL;
+  unsigned char addrspace = MEM_ADDR_SPACE (mem);
   mem = canon_rtx (mem);
 
   if (group_id < 0)
@@ -1548,7 +1552,9 @@ record_store (rtx body, bb_info_t bb_info)
       while (!s_info->is_set)
 	s_info = s_info->next;
 
-      if (s_info->group_id == group_id && s_info->cse_base == base)
+      if (s_info->group_id == group_id
+	  && s_info->cse_base == base
+	  && s_info->addrspace == addrspace)
 	{
 	  HOST_WIDE_INT i;
 	  if (dump_file && (dump_flags & TDF_DETAILS))
@@ -1688,6 +1694,7 @@ record_store (rtx body, bb_info_t bb_info)
   store_info->rhs = rhs;
   store_info->const_rhs = const_rhs;
   store_info->redundant_reason = redundant_reason;
+  store_info->addrspace = addrspace;
 
   /* If this is a clobber, we return 0.  We will only be able to
      delete this insn if there is only one store USED store, but we
diff --git a/gcc/testsuite/gcc.target/i386/addr-space-6.c b/gcc/testsuite/gcc.target/i386/addr-space-6.c
new file mode 100644
index 00000000000..82eca4d7e0c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/addr-space-6.c
@@ -0,0 +1,21 @@
+/* PR rtl-optimization/102733 */
+/* { dg-do compile } */
+/* { dg-options "-O1" } */
+
+/* DSE was removing a store to fs:0 (correctly)
+   and gs:0 (incorrectly) as DSE didn't take into
+   account the address space was different.  */
+
+void test_null_store (void)
+{
+  int __seg_fs *fs = (int __seg_fs *)0;
+  *fs = 1;   
+
+  int __seg_gs *gs = (int __seg_gs *)0;
+  *gs = 2;   
+  *fs = 3;   
+}
+
+/* { dg-final { scan-assembler-times "movl\t" 2 } } */
+/* { dg-final { scan-assembler "gs:" } } */
+/* { dg-final { scan-assembler "fs:" } } */