diff --git a/cranelift/codegen/src/context.rs b/cranelift/codegen/src/context.rs
index 81b9dcbd23..842a48ab21 100644
--- a/cranelift/codegen/src/context.rs
+++ b/cranelift/codegen/src/context.rs
@@ -457,10 +457,8 @@ impl Context {
     #[cfg(feature = "souper-harvest")]
     pub fn souper_harvest(
         &mut self,
-        isa: &dyn TargetIsa,
         out: &mut std::sync::mpsc::Sender<String>,
     ) -> CodegenResult<()> {
-        self.preopt(isa)?;
         do_souper_harvest(&self.func, out);
         Ok(())
     }
diff --git a/cranelift/src/souper_harvest.rs b/cranelift/src/souper_harvest.rs
index 4167611b72..6c15547ae1 100644
--- a/cranelift/src/souper_harvest.rs
+++ b/cranelift/src/souper_harvest.rs
@@ -71,7 +71,11 @@ pub fn run(target: &str, input: &str, output: &str, flag_set: &[String]) -> Resu
             let mut ctx = Context::new();
             ctx.func = func;
 
-            ctx.souper_harvest(fisa.isa.unwrap(), send)
+            ctx.compute_cfg();
+            ctx.preopt(fisa.isa.unwrap())
+                .map_err(|e| format!("failed to run preopt: {}", e))?;
+
+            ctx.souper_harvest(send)
                 .map_err(|e| format!("failed to run souper harvester: {}", e))?;
 
             Ok(())