In some situations, loads and others instructions can be
unreachable already when linearized, for example in code like:
void foo(int *ptr)
{
return;
*ptr;
}
Such loads are detected in find_dominating_stores() and must
be discarded. This is done and the load have its opcode set
to OP_LNOP (wich is only useful for debugging) but it's
address is left as being used by the load.
Fix this by removing the address usage.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
flow.c | 2 +-
validation/mem2reg/load-deadborn.c | 9 +++++++++
2 files changed, 10 insertions(+), 1 deletion(-)
create mode 100644 validation/mem2reg/load-deadborn.c
diff --git a/flow.c b/flow.c
index c614a11d9..528c8f32d 100644
--- a/flow.c
+++ b/flow.c
@@ -479,7 +479,7 @@ static int find_dominating_stores(pseudo_t pseudo, struct instruction *insn,
/* Unreachable load? Undo it */
if (!bb) {
- insn->opcode = OP_LNOP;
+ kill_use(&insn->src);
return 1;
}
diff --git a/validation/mem2reg/load-deadborn.c b/validation/mem2reg/load-deadborn.c
new file mode 100644
index 000000000..fa0baeae8
--- /dev/null
+++ b/validation/mem2reg/load-deadborn.c
@@ -0,0 +1,9 @@
+static void foo(int a)
+{
+ return;
+ a;
+}
+
+/*
+ * check-name: load-deadborn
+ */
--
2.16.0
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