Code pushing (#807)

Push code forward, potentially letting it not execute

1 files changed, 218 insertions, 0 deletions

diff --git a/test/passes/code-pushing.wast b/test/passes/code-pushing.wast
new file mode 100644
index 000000000..ca973e182
--- /dev/null
+++ b/test/passes/code-pushing.wast
@@ -0,0 +1,218 @@
+(module
+  (func $push1
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+    )
+  )
+  (func $push2
+    (local $x i32)
+    (local $y i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (set_local $y (i32.const 3))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+      (drop (get_local $y))
+    )
+  )
+  (func $push1-twice
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (br_if $out (i32.const 2))
+      (br_if $out (i32.const 3))
+      (drop (get_local $x))
+    )
+  )
+  (func $push1-twiceb
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (br_if $out (i32.const 2))
+      (nop)
+      (br_if $out (i32.const 3))
+      (drop (get_local $x))
+    )
+  )
+  (func $push2-twice
+    (local $x i32)
+    (local $y i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (set_local $y (i32.const 3))
+      (br_if $out (i32.const 2))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+      (drop (get_local $y))
+    )
+  )
+  (func $ignore-last
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (br_if $out (i32.const 2))
+    )
+  )
+  (func $ignore-last2
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (nop)
+      (nop)
+      (br_if $out (i32.const 2))
+    )
+  )
+  (func $push-if
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (if (i32.const 2) (nop))
+      (drop (get_local $x))
+    )
+  )
+  (func $push-dropped (result i32)
+    (local $x i32)
+    (block $out i32
+      (set_local $x (i32.const 1))
+      (drop (br_if $out (i32.const 2) (i32.const 3)))
+      (drop (get_local $x))
+      (i32.const 4)
+    )
+  )
+  (func $push-past-stuff
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (call $push-past-stuff)
+      (drop (i32.const 1))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+    )
+  )
+  (func $fail-then-push
+    (local $x i32)
+    (local $y i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (drop (get_local $x))
+      (br_if $out (i32.const 2))
+      (set_local $y (i32.const 1))
+      (br_if $out (i32.const 3))
+      (drop (get_local $x))
+      (drop (get_local $y))
+    )
+  )
+  ;; and now for stuff that should *not* be pushed
+  (func $used
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (br_if $out (get_local $x))
+      (drop (get_local $x))
+    )
+  )
+  (func $not-sfa
+    (local $x i32)
+    (set_local $x (i32.const 1))
+    (block $out
+      (set_local $x (i32.const 1))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+    )
+  )
+  (func $not-sfa2
+    (local $x i32)
+    (drop (get_local $x))
+    (block $out
+      (set_local $x (i32.const 1))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+    )
+  )
+  (func $used-out
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.const 1))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+    )
+    (drop (get_local $x))
+  )
+  (func $value-might-interfere ;; but doesn't
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.load (i32.const 0)))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+    )
+  )
+  (func $value-interferes
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.load (i32.const 0)))
+      (i32.store (i32.const 1) (i32.const 3))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+    )
+  )
+  (func $value-interferes-accumulation
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.load (i32.const 0)))
+      (nop)
+      (i32.store (i32.const 1) (i32.const 3))
+      (nop)
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+    )
+  )
+  (func $value-interferes-in-pushpoint
+    (local $x i32)
+    (block $out
+      (set_local $x (i32.load (i32.const 0)))
+      (if (i32.const 1)
+        (call $value-interferes)
+      )
+      (drop (get_local $x))
+    )
+  )
+  (func $values-might-interfere ;; but don't, as we keep the order
+    (local $x i32)
+    (local $y i32)
+    (block $out
+      (set_local $x (call $push-dropped))
+      (set_local $y (call $push-dropped))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+      (drop (get_local $y))
+    )
+  )
+  (func $unpushed-interferes
+    (local $x i32)
+    (local $y i32)
+    (block $out
+      (set_local $x (call $push-dropped))
+      (set_local $y (call $push-dropped))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+      (drop (get_local $y))
+    )
+    (drop (get_local $y)) ;; $y can't be pushed, so x can't be
+  )
+  (func $unpushed-ignorable
+    (local $x i32)
+    (local $y i32)
+    (block $out
+      (set_local $x (call $push-dropped))
+      (set_local $y (call $push-dropped))
+      (br_if $out (i32.const 2))
+      (drop (get_local $x))
+      (drop (get_local $y))
+    )
+    (drop (get_local $x)) ;; $x can't be pushed, but y doesn't care
+  )
+)
+