As Marc noted, DCE will remove the isolated *0 which defeats the purpose
of the most recent patch. This marks any isolated null pointer
dereferences as volatile which ensures they don't go away.
This also fixes a comment and tests that the dereferences survive until
the optimized dump.
Bootstrapped and regression tested on x86_64-unknown-linux-gnu.
Installed on the trunk.
Jeff
* gimple-ssa-isolate-paths.c (check_loadstore): Mark discovered
memory references as volatile.
(insert_trap_and_remove_trailing_statements): Fix comment.
* gcc.dg/tree-ssa/isolate-1.c: Update expected output.
* gcc.dg/tree-ssa/isolate-5.c: Verify the load survives through
the SSA optimizers.
diff --git a/gcc/gimple-ssa-isolate-paths.c b/gcc/gimple-ssa-isolate-paths.c
index 48ab604..2d8f176 100644
--- a/gcc/gimple-ssa-isolate-paths.c
+++ b/gcc/gimple-ssa-isolate-paths.c
@@ -51,7 +51,12 @@ check_loadstore (gimple stmt ATTRIBUTE_UNUSED, tree op, void
*data)
{
if ((TREE_CODE (op) == MEM_REF || TREE_CODE (op) == TARGET_MEM_REF)
&& operand_equal_p (TREE_OPERAND (op, 0), (tree)data, 0))
- return true;
+ {
+ TREE_THIS_VOLATILE (op) = 1;
+ TREE_SIDE_EFFECTS (op) = 1;
+ update_stmt (stmt);
+ return true;
+ }
return false;
}
@@ -64,7 +69,7 @@ insert_trap_and_remove_trailing_statements
(gimple_stmt_iterator *si_p, tree op)
code that wishes to catch the signal can do so.
If the dereference is a load, then there's nothing to do as the
- LHS will be a throw-away SSA_NAME and the LHS is the NULL dereference.
+ LHS will be a throw-away SSA_NAME and the RHS is the NULL dereference.
If the dereference is a store and we can easily transform the RHS,
then simplify the RHS to enable more DCE. */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/isolate-1.c
b/gcc/testsuite/gcc.dg/tree-ssa/isolate-1.c
index 33745ba..f1f3101 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/isolate-1.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/isolate-1.c
@@ -50,7 +50,7 @@ d_type (struct d_info *di)
and finally that we set the RHS of the store to zero. */
/* { dg-final { scan-tree-dump-times "__builtin_trap" 1 "isolate-paths"} } */
/* { dg-final { scan-tree-dump-times "->type = 42" 1 "isolate-paths"} } */
-/* { dg-final { scan-tree-dump-times "->type = 0" 1 "isolate-paths"} } */
+/* { dg-final { scan-tree-dump-times "->type ={v} 0" 1 "isolate-paths"} } */
/* { dg-final { scan-tree-dump-times "->zzz" 1 "isolate-paths"} } */
/* { dg-final { cleanup-tree-dump "isolate-paths" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/isolate-5.c
b/gcc/testsuite/gcc.dg/tree-ssa/isolate-5.c
index a70871e..ee587d2 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/isolate-5.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/isolate-5.c
@@ -1,6 +1,6 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-isolate-paths" } */
+/* { dg-options "-O2 -fdump-tree-isolate-paths -fdump-tree-optimized" } */
struct demangle_component
@@ -51,9 +51,11 @@ d_type (struct d_info *di)
We leave the 0->type in the IL, so expect to see ->type twice. */
/* { dg-final { scan-tree-dump-times "__builtin_trap" 1 "isolate-paths"} } */
/* { dg-final { scan-tree-dump-times "->type" 2 "isolate-paths"} } */
+/* { dg-final { scan-tree-dump-times "->type" 1 "optimized"} } */
+/* { dg-final { scan-tree-dump-times "\\.type" 1 "optimized"} } */
/* { dg-final { scan-tree-dump-times "->zzz" 1 "isolate-paths"} } */
/* { dg-final { cleanup-tree-dump "isolate-paths" } } */
-
+/* { dg-final { cleanup-tree-dump "optimized-paths" } } */
