[gcc r12-3874] Fix null-pointer dereference in delete_dead_or_redundant_call [PR102451]

[Feng Xue]

https://gcc.gnu.org/g:f91b11eb8891f3ae910eb3b2e4a48e2d7d670d2d

commit r12-3874-gf91b11eb8891f3ae910eb3b2e4a48e2d7d670d2d
Author: Feng Xue <fxue@os.amperecomputing.com>
Date:   Thu Sep 23 08:47:45 2021 +0800

    Fix null-pointer dereference in delete_dead_or_redundant_call [PR102451]
    
    2021-09-23  Feng Xue  <fxue@os.amperecomputing.com>
    
    gcc/
            PR tree-optimization/102451
            * tree-ssa-dse.c (delete_dead_or_redundant_call): Record bb of stmt
            before removal.

Diff:
---
 gcc/tree-ssa-dse.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c
index 98daa8ab24c..27287fe88ee 100644
--- a/gcc/tree-ssa-dse.c
+++ b/gcc/tree-ssa-dse.c
@@ -978,6 +978,7 @@ delete_dead_or_redundant_call (gimple_stmt_iterator *gsi, const char *type)
       fprintf (dump_file, "\n");
     }
 
+  basic_block bb = gimple_bb (stmt);
   tree lhs = gimple_call_lhs (stmt);
   if (lhs)
     {
@@ -985,7 +986,7 @@ delete_dead_or_redundant_call (gimple_stmt_iterator *gsi, const char *type)
       gimple *new_stmt = gimple_build_assign (lhs, ptr);
       unlink_stmt_vdef (stmt);
       if (gsi_replace (gsi, new_stmt, true))
-        bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index);
+	bitmap_set_bit (need_eh_cleanup, bb->index);
     }
   else
     {
@@ -994,7 +995,7 @@ delete_dead_or_redundant_call (gimple_stmt_iterator *gsi, const char *type)
 
       /* Remove the dead store.  */
       if (gsi_remove (gsi, true))
-	bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index);
+	bitmap_set_bit (need_eh_cleanup, bb->index);
       release_defs (stmt);
     }
 }