This fixes PR51692, we shouldn't remove the lhs of allocation
calls before the special malloc/free pair removal code kicks in.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Richard.
2012-01-03 Richard Guenther <rguent...@suse.de>
PR tree-optimization/51692
* tree-ssa-dce.c (eliminate_unnecessary_stmts): Do not remove
the LHS of allocation stmts.
* gcc.dg/torture/pr51692.c: New testcase.
Index: gcc/tree-ssa-dce.c
===================================================================
--- gcc/tree-ssa-dce.c (revision 182829)
+++ gcc/tree-ssa-dce.c (working copy)
@@ -1329,31 +1329,38 @@ eliminate_unnecessary_stmts (void)
}
else if (is_gimple_call (stmt))
{
- call = gimple_call_fndecl (stmt);
- if (call)
- {
- tree name;
+ tree name = gimple_call_lhs (stmt);
- /* When LHS of var = call (); is dead, simplify it into
- call (); saving one operand. */
- name = gimple_call_lhs (stmt);
- if (name && TREE_CODE (name) == SSA_NAME
- && !TEST_BIT (processed, SSA_NAME_VERSION (name)))
- {
- something_changed = true;
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Deleting LHS of call: ");
- print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
- fprintf (dump_file, "\n");
- }
+ notice_special_calls (stmt);
- gimple_call_set_lhs (stmt, NULL_TREE);
- maybe_clean_or_replace_eh_stmt (stmt, stmt);
- update_stmt (stmt);
- release_ssa_name (name);
+ /* When LHS of var = call (); is dead, simplify it into
+ call (); saving one operand. */
+ if (name
+ && TREE_CODE (name) == SSA_NAME
+ && !TEST_BIT (processed, SSA_NAME_VERSION (name))
+ /* Avoid doing so for allocation calls which we
+ did not mark as necessary, it will confuse the
+ special logic we apply to malloc/free pair removal. */
+ && (!(call = gimple_call_fndecl (stmt))
+ || DECL_BUILT_IN_CLASS (call) != BUILT_IN_NORMAL
+ || (DECL_FUNCTION_CODE (call) != BUILT_IN_MALLOC
+ && DECL_FUNCTION_CODE (call) != BUILT_IN_CALLOC
+ && DECL_FUNCTION_CODE (call) != BUILT_IN_ALLOCA
+ && (DECL_FUNCTION_CODE (call)
+ != BUILT_IN_ALLOCA_WITH_ALIGN))))
+ {
+ something_changed = true;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Deleting LHS of call: ");
+ print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
+ fprintf (dump_file, "\n");
}
- notice_special_calls (stmt);
+
+ gimple_call_set_lhs (stmt, NULL_TREE);
+ maybe_clean_or_replace_eh_stmt (stmt, stmt);
+ update_stmt (stmt);
+ release_ssa_name (name);
}
}
}
Index: gcc/testsuite/gcc.dg/torture/pr51692.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr51692.c (revision 0)
+++ gcc/testsuite/gcc.dg/torture/pr51692.c (revision 0)
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+
+int
+main ()
+{
+ volatile double d = 0.0;
+ double *p = __builtin_calloc (1, sizeof (double));
+ d += 1.0;
+ *p += 2.0;
+ __builtin_free (p);
+ return 0;
+}
+
