[clang] [compiler-rt] [Sanitizer] add signed-integer-wrap sanitizer (PR #80089)

[Justin Stitt via cfe-commits]

================
@@ -0,0 +1,77 @@
+// Check that -fsanitize=signed-integer-wrap instruments with -fwrapv
----------------
JustinStitt wrote:

I believe @tschuett was saying that to be confident we are instrumenting the arithmetic (and the correct operands therein) we should check the overflow bit usage in the branch instruction. The only way I could think of doing this was capturing the call to the overflow intrinsic which returns the value and the overflow bit. Is there a way to minimize my CHECKs?

https://github.com/llvm/llvm-project/pull/80089