Only pass -Zincremental-verify-ich for incremental compiles

Author: xmakro

collector/src/bin/rustc-fake.rs

@@ -82,7 +82,16 @@ fn main() {
     // avoid. rustc-perf can accept the higher cost of always verifying hashes,
     // and we currently prefer to avoid exposing a means of hard-disabling
     // verification.
-    args.push(OsString::from("-Zincremental-verify-ich"));
+    //
+    // Only pass this for incremental compiles. For non-incremental compiles
+    // the flag only triggers a costly query key verification sweep.
+    let is_incremental = args.iter().any(|arg| {
+        arg.to_str()
+            .is_some_and(|a| a.starts_with("incremental=") || a.starts_with("-Cincremental="))
+    });
+    if is_incremental {
+        args.push(OsString::from("-Zincremental-verify-ich"));
+    }
 
     if let Some(pos) = args.iter().position(|arg| arg == "--wrap-rustc-with") {
         // Strip out the flag and its argument, and run rustc under the wrapper