[WebAssembly] Add an assertion for an invalid CFG
Summary:
It was not easy to provide a test case for D45648 (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.
Reviewers: dblaikie
Subscribers: jfb, dschuff, sbc100, jgravelle-google, llvm-commits, dblaikie
Differential Revision: https://reviews.llvm.org/D45711
llvm-svn: 330217
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
index 12664e6..9e0a945 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
+++ b/llvm/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 =