[clang] [analyzer] use `invalidateRegions()` in `VisitGCCAsmStmt` (PR #109838)

[Balazs Benics via cfe-commits]

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@@ -40,7 +42,19 @@ void testInlineAsmMemcpyUninit(void)
 {
     int a[10], b[10] = {}, c;
     MyMemcpy(&a[1], &b[1], sizeof(b) - sizeof(b[1]));
-    c = a[0]; // expected-warning{{Assigned value is garbage or undefined}}
+    c = a[0]; // FIXME: should be warning about uninitialized value, but invalidateRegions() also
+              // invalidates super region.
+}
+
+void testInlineAsmMemcpyUninitLoop(const void *src, unsigned long len)
+{
+    int a[10], c;
+    unsigned long toCopy = sizeof(a) < len ? sizeof(a) : len;
+
+    MyMemcpy(a, src, toCopy);
+
+    for (unsigned long i = 0; i < toCopy; ++i)
+      c = a[i]; // no-warning
----------------
steakhal wrote:

I'd suggest avoiding loops because we may decide to change how and how many times the loop body will be checked.
You could change the test to explicitly have two guarded blocks: 1) where "toCopy" is "len", and 2) "toCopy" is "sizeof(a)" (aka. 40). Then you could explicitly subscript `a` with the relevant indicies.

https://github.com/llvm/llvm-project/pull/109838