[clang] [C] Add -Wjump-bypasses-init (PR #138009)

[Aaron Ballman via cfe-commits]

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@@ -0,0 +1,31 @@
+// RUN: %clang_cc1 -fsyntax-only -verify=c,both -Wjump-bypasses-init %s
+// RUN: %clang_cc1 -fsyntax-only -verify=c,both -Wc++-compat %s
+// RUN: %clang_cc1 -fsyntax-only -verify=good %s
+// RUN: %clang_cc1 -fsyntax-only -verify=cxx,both -x c++ %s
+// good-no-diagnostics
+
+void goto_func_1(void) {
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AaronBallman wrote:

These are fun examples. It turns out that this code is accepted in both C and C++ despite jumping over the initialization, in both Clang and GCC. I'm not convinced that's a good design, but I don't think this patch changes the behavior either, and so I don't think we should diagnose. However, perhaps we should in a follow-up, so I've filed: https://github.com/llvm/llvm-project/issues/138257 and added these as negative tests for this PR.

https://github.com/llvm/llvm-project/pull/138009