[clang] [Clang] Fix constexpr __builtin_(add|sub|mul)_overflow bugs (PR #192568)

[via cfe-commits]

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@@ -1964,6 +1964,53 @@ namespace I128Mul {
 }
 #endif
 
+namespace OverflowOps {
+  constexpr bool add_bool() {
+    bool r = false;
+    return __builtin_add_overflow(1u, 1u, &r) && r == false;
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widberg wrote:

Personally, I would expect that to compile, as it does right now. At least based on my understanding of the docs https://clang.llvm.org/docs/LanguageExtensions.html#checked-arithmetic-builtins. Also, GCC isn't happy because it explicitly forbids bools (https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html), whereas Clang explicitly allows them.

https://github.com/llvm/llvm-project/pull/192568