[NFC] Add a test for inlining a function that traps (#4966)

I don't see an existing test for this, and it's useful behavior since such inlining will
propagate the trap to the caller, possibly helping DCE and other things there, so it's
good to have a test to guarantee we never break it.

1 files changed, 68 insertions, 0 deletions

diff --git a/test/lit/passes/inlining-unreachable.wast b/test/lit/passes/inlining-unreachable.wast
new file mode 100644
index 000000000..4cec297e4
--- /dev/null
+++ b/test/lit/passes/inlining-unreachable.wast
@@ -0,0 +1,68 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; RUN: foreach %s %t wasm-opt --inlining -S -o - | filecheck %s
+
+;; Test that we inline functions with unreachable bodies. This is important to
+;; propagate the trap to the caller (where it might lead to DCE).
+
+(module
+  (func $trap
+    (unreachable)
+  )
+  ;; CHECK:      (type $none_=>_none (func))
+
+  ;; CHECK:      (type $none_=>_i32 (func (result i32)))
+
+  ;; CHECK:      (func $call-trap
+  ;; CHECK-NEXT:  (block $__inlined_func$trap
+  ;; CHECK-NEXT:   (unreachable)
+  ;; CHECK-NEXT:   (br $__inlined_func$trap)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $call-trap
+    ;; In this case the call had type none, but the inlined code is unreachable,
+    ;; so we'll add a br to the new block to keep the type as none (the br is
+    ;; not actually reached, and other opts will remove it).
+    (call $trap)
+  )
+
+  (func $trap-result (result i32)
+    ;; As above, but now there is a declared result.
+    (unreachable)
+  )
+
+  ;; CHECK:      (func $call-trap-result (result i32)
+  ;; CHECK-NEXT:  (block $__inlined_func$trap-result (result i32)
+  ;; CHECK-NEXT:   (unreachable)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $call-trap-result (result i32)
+    (call $trap-result)
+  )
+
+  (func $contents-then-trap
+    ;; Add some contents in addition to the trap.
+    (nop)
+    (drop
+      (i32.const 1337)
+    )
+    (nop)
+    (unreachable)
+  )
+  ;; CHECK:      (func $call-contents-then-trap
+  ;; CHECK-NEXT:  (block $__inlined_func$contents-then-trap
+  ;; CHECK-NEXT:   (block
+  ;; CHECK-NEXT:    (nop)
+  ;; CHECK-NEXT:    (drop
+  ;; CHECK-NEXT:     (i32.const 1337)
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:    (nop)
+  ;; CHECK-NEXT:    (unreachable)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (br $__inlined_func$contents-then-trap)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $call-contents-then-trap
+    (call $contents-then-trap)
+  )
+)