[WebAssembly] Fix a bug deleting instruction in a ranged for loop

Summary: We shouldn't delete elements while iterating a ranged for loop.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58519

llvm-svn: 354844
diff --git a/llvm/test/CodeGen/WebAssembly/exception.ll b/llvm/test/CodeGen/WebAssembly/exception.ll
index 35cbaaa..13f9c18 100644
--- a/llvm/test/CodeGen/WebAssembly/exception.ll
+++ b/llvm/test/CodeGen/WebAssembly/exception.ll
@@ -340,6 +340,26 @@
   ret void
 }
 
+; When the result of @llvm.wasm.get.exception is not used. This is created to
+; fix a bug in LateEHPrepare and this should not crash.
+define void @test_get_exception_wo_use() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+entry:
+  invoke void @foo()
+          to label %try.cont unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %0 = catchswitch within none [label %catch.start] unwind to caller
+
+catch.start:                                      ; preds = %catch.dispatch
+  %1 = catchpad within %0 [i8* null]
+  %2 = call i8* @llvm.wasm.get.exception(token %1)
+  %3 = call i32 @llvm.wasm.get.ehselector(token %1)
+  catchret from %1 to label %try.cont
+
+try.cont:                                         ; preds = %entry, %catch.start
+  ret void
+}
+
 declare void @foo()
 declare void @bar(i32*)
 declare i32 @__gxx_wasm_personality_v0(...)