AvoidReinterprets should not remove code around a reinterpret's value's fallthrough (#2989)

We can turn a reinterpret of a load into a different load, and so forth, but if
the reinterpret has a non-load child with a load fallthrough, that's not good
enough - we can't remove the extra code:

(reinterpret
  (block
    ..extra code..
    (load)
  )
)

That can't be turned into a load of the flipped type.

2 files changed, 33 insertions, 0 deletions

diff --git a/test/passes/avoid-reinterprets.txt b/test/passes/avoid-reinterprets.txt
index 410132a84..d14484460 100644
--- a/test/passes/avoid-reinterprets.txt
+++ b/test/passes/avoid-reinterprets.txt
@@ -163,4 +163,20 @@
    )
   )
  )
+ (func $nofallthrough
+  (local $x i32)
+  (local.set $x
+   (i32.load
+    (i32.const 1024)
+   )
+  )
+  (drop
+   (f32.reinterpret_i32
+    (block $block (result i32)
+     (nop)
+     (local.get $x)
+    )
+   )
+  )
+ )
 )
diff --git a/test/passes/avoid-reinterprets.wast b/test/passes/avoid-reinterprets.wast
index 296b16df3..068df437c 100644
--- a/test/passes/avoid-reinterprets.wast
+++ b/test/passes/avoid-reinterprets.wast
@@ -49,4 +49,21 @@
     )
    )
   )
+  (func $nofallthrough
+    (local $x i32)
+    (local.set $x
+     (i32.load
+      (i32.const 1024)
+     )
+    )
+    (drop
+     (f32.reinterpret_i32
+      (block (result i32)
+       (nop) ;; this would be removed by other opts, but in general, we can't
+             ;; just look at the fallthrough, as we can't just remove code here
+       (local.get $x)
+      )
+     )
+    )
+  )
 )