[PATCH 4/5] kill parent's dead stores too

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

kill_dominated_stores() identify and remove dead stores
(stores unneeded because the same location is overwritten later
by another store) only when both stores are in the same basic block.

Slightly improve this by also handling the case when the dead store
is in a parent BB of the "live" store.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 memops.c                                    | 16 ++++++++++++++++
 validation/memops/kill-dead-store-parent0.c |  1 -
 validation/memops/kill-dead-store-parent2.c |  1 -
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/memops.c b/memops.c
index 8020f2e6cf03..44d90754d279 100644
--- a/memops.c
+++ b/memops.c
@@ -231,6 +231,7 @@ static void kill_dominated_stores(struct basic_block *bb)
 		if (!insn->bb)
 			continue;
 		if (insn->opcode == OP_STORE) {
+			struct basic_block *par;
 			struct instruction *dom;
 			pseudo_t pseudo = insn->src;
 			int local;
@@ -249,6 +250,21 @@ static void kill_dominated_stores(struct basic_block *bb)
 			} END_FOR_EACH_PTR_REVERSE(dom);
 
 			/* OK, we should check the parents now */
+			FOR_EACH_PTR(bb->parents, par) {
+
+				if (bb_list_size(par->children) != 1)
+					goto next_parent;
+				FOR_EACH_PTR(par->insns, dom) {
+					if (!dom->bb)
+						continue;
+					if (dom == insn)
+						goto next_parent;
+					if (!try_to_kill_store(pseudo, insn, dom, local))
+						goto next_parent;
+				} END_FOR_EACH_PTR(dom);
+next_parent:
+				;
+			} END_FOR_EACH_PTR(par);
 		}
 next_store:
 		/* Do the next one */;
diff --git a/validation/memops/kill-dead-store-parent0.c b/validation/memops/kill-dead-store-parent0.c
index 1413134b8c23..c1b2466ca450 100644
--- a/validation/memops/kill-dead-store-parent0.c
+++ b/validation/memops/kill-dead-store-parent0.c
@@ -8,7 +8,6 @@ void foo(int *ptr, int p)
 /*
  * check-name: kill-dead-store-parent0
  * check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
  *
  * check-output-ignore
  * check-output-pattern(1): store
diff --git a/validation/memops/kill-dead-store-parent2.c b/validation/memops/kill-dead-store-parent2.c
index b563fd31b669..4f7b9dd901d9 100644
--- a/validation/memops/kill-dead-store-parent2.c
+++ b/validation/memops/kill-dead-store-parent2.c
@@ -19,7 +19,6 @@ l20:
 /*
  * check-name: kill-dead-store-parent2
  * check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
  *
  * check-output-ignore
  * check-output-pattern(1): store
-- 
2.31.1