[PATCH] tree-optimization/109139 - fix .DEFERRED_INIT removal

[Richard Biener <rguenther@suse.de>]

The following make sure to strip MEMs when looking for unused
decls on the LHS of .DEFERRED_INIT.

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

	PR tree-optimization/109139
	* tree-ssa-live.cc (remove_unused_locals): Look at the
	base address for unused decls on the LHS of .DEFERRED_INIT.

	* gcc.dg/torture/pr109139.c: New testcase.
---
 gcc/testsuite/gcc.dg/torture/pr109139.c | 12 ++++++++++++
 gcc/tree-ssa-live.cc                    |  3 ++-
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr109139.c

diff --git a/gcc/testsuite/gcc.dg/torture/pr109139.c b/gcc/testsuite/gcc.dg/torture/pr109139.c
new file mode 100644
index 00000000000..9fa97ebc665
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr109139.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-ftrivial-auto-var-init=zero" } */
+
+const int COMPARE_CANDIDATE;
+char ipmi_ek_compare_link_record1_0, ipmi_ek_compare_link_record2_0;
+void ipmi_ek_compare_link()
+{
+  for (; ipmi_ek_compare_link_record1_0;)
+    for (; ipmi_ek_compare_link_record2_0;) {
+	int link[COMPARE_CANDIDATE];
+    }
+}
diff --git a/gcc/tree-ssa-live.cc b/gcc/tree-ssa-live.cc
index 9118e82b4f1..1be92956cc5 100644
--- a/gcc/tree-ssa-live.cc
+++ b/gcc/tree-ssa-live.cc
@@ -897,7 +897,8 @@ remove_unused_locals (void)
 	    else if (gimple_call_internal_p (stmt, IFN_DEFERRED_INIT))
 	      {
 		tree lhs = gimple_call_lhs (stmt);
-		if (DECL_P (lhs) && !is_used_p (lhs))
+		tree base = get_base_address (lhs);
+		if (DECL_P (base) && !is_used_p (base))
 		  {
 		    unlink_stmt_vdef (stmt);
 		    gsi_remove (&gsi, true);
-- 
2.35.3