[clang] [analyzer] Model overflow builtins (PR #102602)

[Balazs Benics via cfe-commits]

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@@ -0,0 +1,157 @@
+// RUN: %clang_analyze_cc1 -triple x86_64-unknown-unknown -verify %s \
+// RUN:   -analyzer-checker=core,debug.ExprInspection
+
+#define __UINT_MAX__ (__INT_MAX__ * 2U + 1U)
+#define __INT_MIN__  (-__INT_MAX__ - 1)
+
+void clang_analyzer_dump_int(int);
+void clang_analyzer_dump_long(long);
+void clang_analyzer_eval(int);
+void clang_analyzer_warnIfReached(void);
+
+void test_add_nooverflow(void)
+{
+   int res;
+
+   if (__builtin_add_overflow(10, 20, &res)) {
+     clang_analyzer_warnIfReached();
+     return;
+   }
+
+   clang_analyzer_dump_int(res); //expected-warning{{30 S32b}}
+}
+
+void test_add_overflow(void)
+{
+   int res;
+
+   if (__builtin_add_overflow(__INT_MAX__, 1, &res)) {
+     clang_analyzer_dump_int(res); //expected-warning{{1st function call argument is an uninitialized value}}
+     return;
+   }
+
+   clang_analyzer_warnIfReached();
+}
+
+void test_add_underoverflow(void)
+{
+   int res;
+
+   if (__builtin_add_overflow(__INT_MIN__, -1, &res)) {
+     clang_analyzer_dump_int(res); //expected-warning{{1st function call argument is an uninitialized value}}
+     return;
+   }
+
+   clang_analyzer_warnIfReached();
+}
+
+void test_sub_underflow(void)
+{
+   int res;
+
+   if (__builtin_sub_overflow(__INT_MIN__, 10, &res)) {
+     return;
+   }
+
+   clang_analyzer_warnIfReached();
+}
+
+void test_sub_overflow(void)
+{
+   int res;
+
+   if (__builtin_sub_overflow(__INT_MAX__, -1, &res)) {
+     return;
+   }
+
+   clang_analyzer_warnIfReached();
+}
+
+void test_sub_nooverflow(void)
+{
+   int res;
+
+   if (__builtin_sub_overflow(__INT_MAX__, 1, &res)) {
+     clang_analyzer_warnIfReached();
+     return;
+   }
+
+   clang_analyzer_dump_int(res); //expected-warning{{2147483646 S32b}}
+}
+
+void test_mul_overrflow(void)
----------------
steakhal wrote:

```suggestion
void test_mul_overflow(void)
```

https://github.com/llvm/llvm-project/pull/102602