2 files changed, 19 insertions, 2 deletions
diff --git a/simplify.c b/simplify.c
index de115d6d..6619bd1b 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1299,8 +1299,13 @@ static int simplify_cast(struct instruction *insn)
 		}
 		break;
 	case OP_TRUNC:
-		osize = def->orig_type->bit_size;
-		if (insn->opcode == OP_ZEXT && size == osize) {
+		switch (insn->opcode) {
+		case OP_TRUNC:
+			insn->orig_type = def->orig_type;
+			return replace_pseudo(insn, &insn->src1, def->src);
+		case OP_ZEXT:
+			if (size != def->orig_type->bit_size)
+				break;
 			insn->opcode = OP_AND;
 			insn->src2 = value_pseudo((1ULL << def->size) - 1);
 			return replace_pseudo(insn, &insn->src1, def->src);
diff --git a/validation/optim/trunc-trunc.c b/validation/optim/trunc-trunc.c
new file mode 100644
index 00000000..6dc50aee
--- /dev/null
+++ b/validation/optim/trunc-trunc.c
@@ -0,0 +1,12 @@
+char foo(int a)
+{
+	return ((((short) a) + 1) - 1);
+}
+
+/*
+ * check-name: trunc-trunc
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-pattern(1): trunc\\.
+ */