[PATCH] tree-optimization/116079 - store motion and clobbers

[Richard Biener]

When we move a store out of an inner loop and remove a clobber in
the process, analysis of the inner loop can run into the clobber
via the meta-data and crash when accessing its basic-block.  The
following avoids this by clearing the VDEF which is how it identifies
already processed stores.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

        PR tree-optimization/116079
        * tree-ssa-loop-im.cc (hoist_memory_references): Clear
        VDEF of elided clobbers.

        * gcc.dg/torture/pr116079.c: New testcase.
---
 gcc/testsuite/gcc.dg/torture/pr116079.c | 20 ++++++++++++++++++++
 gcc/tree-ssa-loop-im.cc                 |  2 ++
 2 files changed, 22 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr116079.c

diff --git a/gcc/testsuite/gcc.dg/torture/pr116079.c 
b/gcc/testsuite/gcc.dg/torture/pr116079.c
new file mode 100644
index 00000000000..e9120969d91
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr116079.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+
+char g_132;
+int g_701, g_1189, func_24___trans_tmp_15, func_24_l_2691;
+long func_24___trans_tmp_9;
+int *func_24_l_2684;
+void func_24() {
+  for (; g_1189;) {
+    g_132 = 0;
+    for (; g_132 < 6; ++g_132) {
+      func_24___trans_tmp_9 = *func_24_l_2684 = func_24_l_2691;
+      g_701 = 4;
+      for (; g_701; g_701 -= 1) {
+        int l_2748[4];
+        int si2 = l_2748[3];
+        func_24___trans_tmp_15 = si2;
+      }
+    }
+  }
+}
diff --git a/gcc/tree-ssa-loop-im.cc b/gcc/tree-ssa-loop-im.cc
index c53efbb8d59..ccc56dc42f6 100644
--- a/gcc/tree-ssa-loop-im.cc
+++ b/gcc/tree-ssa-loop-im.cc
@@ -2880,6 +2880,7 @@ hoist_memory_references (class loop *loop, bitmap 
mem_refs,
          gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
          unlink_stmt_vdef (stmt);
          release_defs (stmt);
+         gimple_set_vdef (stmt, NULL_TREE);
          gsi_remove (&gsi, true);
        }
 
@@ -3062,6 +3063,7 @@ hoist_memory_references (class loop *loop, bitmap 
mem_refs,
       gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
       unlink_stmt_vdef (stmt);
       release_defs (stmt);
+      gimple_set_vdef (stmt, NULL_TREE);
       gsi_remove (&gsi, true);
     }
 
-- 
2.43.0