[clang] [clang][bytecode] Guard strcmp against differing element types (PR #154777)

[Timm Baeder via cfe-commits]

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@@ -338,3 +338,12 @@ static void *FooTable[1] = {
     }
 };
 
+int strcmp(const char *, const char *); // all-note {{passing argument to parameter here}}
+#define S "\x01\x02\x03\x04\x05\x06\x07\x08"
+const char _str[] = {S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7]};
+const unsigned char _str2[] = {S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7]};
+const int compared = strcmp(_str, (const char *)_str2); // all-error {{initializer element is not a compile-time constant}}
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tbaederr wrote:

The cast causes a `CCEDiag` but we continue evaluation so it reaches the `__builtin_strcmp`.

https://github.com/llvm/llvm-project/pull/154777