[PATCH] D45711: [WebAssembly] Add an assertion for an invalid CFG

[Heejin Ahn via Phabricator via llvm-commits]

aheejin created this revision.
aheejin added reviewers: sunfish, yurydelendik, dblaikie.
Herald added subscribers: llvm-commits, jgravelle-google, sbc100, dschuff, jfb.

It was not easy to provide a test case for https://reviews.llvm.org/D45648 (https://reviews.llvm.org/rL330079) because the bug
didn't manifest itself in the set of currently valid IRs. Added an assertion to
check this faster, thanks to @dblaikie's suggestion.


Repository:
  rL LLVM

https://reviews.llvm.org/D45711

Files:
  lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp


Index: lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
===================================================================
--- lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
+++ lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
@@ -145,6 +145,9 @@
            std::prev(InsertPos)->getOpcode() != WebAssembly::END_LOOP)
       --InsertPos;
   }
+  // The header block in which a 'block' mark will be inserted should have a
+  // terminator because it is branching to a non-layout successor.
+  assert(InsertPos != Header->end());
 
   // Add the BLOCK.
   MachineInstr *Begin =


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