[clang] [analyzer] Simplify SVal for simple NonLoc->Loc casts (PR #66463)

[Balazs Benics via cfe-commits]

================
@@ -0,0 +1,31 @@
+// RUN: %clang_analyze_cc1 %s \
+// RUN:   -analyzer-checker=core \
+// RUN:   -analyzer-checker=debug.ExprInspection \
+// RUN:   -analyzer-config eagerly-assume=false \
+// RUN:   -verify
+
+void clang_analyzer_eval(int);
+
+void test_simplified_before_cast_add(long long t1) {
+  long long t2 = t1 + 3;
+  if (!t2) {
+    int *p = (int *) t2;
+    clang_analyzer_eval(p == 0); // expected-warning{{TRUE}}
+  }
+}
+
+void test_simplified_before_cast_sub(long long t1) {
+  long long t2 = t1 - 3;
+  if (!t2) {
+    int *p = (int *) t2;
+    clang_analyzer_eval(p == 0); // expected-warning{{TRUE}}
+  }
+}
+
+void test_simplified_before_cast_mul(long long t1) {
+  long long t2 = t1 * 3;
+  if (!t2) {
+    int *p = (int *) t2;
+    clang_analyzer_eval(p == 0); // expected-warning{{TRUE}}
+  }
+}
----------------
steakhal wrote:

I think I'd prefer to look for a place where similar things are tested and add these there.

https://github.com/llvm/llvm-project/pull/66463