[clang] Modify BoundsSan to improve debuggability (PR #65972)

[Oskar Wirga via cfe-commits]

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@@ -0,0 +1,83 @@
+; RUN: llc -O3 -mtriple arm64-linux -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-ASM
+; What this test does is check that even with nomerge, the functions still get merged in
+; compiled code as the ubsantrap call gets lowered to a single instruction: brk.
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oskarwirga wrote:

I understood your comment on the Phabricator diff as a request for this test:

> can you please create a test where bounds-checking-single-trap=0 and setCannotMerge produce invalid result.

I will also add a test in `llvm/test/Instrumentation/BoundsChecking/`

https://github.com/llvm/llvm-project/pull/65972