Add an optimisation pass to combine variables if possible

This optimisation re-uses variables if possible, rather than
allocating new ones.

2 files changed, 21 insertions, 0 deletions

diff --git a/test/c/non_unique.expect b/test/c/non_unique.expect
new file mode 100644
index 00000000..9766475a
--- /dev/null
+++ b/test/c/non_unique.expect
@@ -0,0 +1 @@
+ok
diff --git a/test/c/non_unique.sail b/test/c/non_unique.sail
new file mode 100644
index 00000000..eda7720d
--- /dev/null
+++ b/test/c/non_unique.sail
@@ -0,0 +1,20 @@
+default Order dec
+
+$include <prelude.sail>
+
+val "print_endline" : string -> unit
+
+function f(_: int) -> unit = ()
+function g(_: bits(1)) -> unit = ()
+
+function main(() : unit) -> unit = {
+  let y : int = {
+    let x : int = 3;
+    x
+  };
+  {
+    let x : bits(1) = 0b0;
+    g(x)
+  };
+  print_endline("ok");
+}
\ No newline at end of file