Auto merge of #54416 - christianpoveda:master, r=wesleywiser

Extend MIR inlining to all operand variants

This fixes #54193
r? @eddyb

src/librustc_mir/transform/inline.rs

@@ -94,8 +94,8 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
                 // Only consider direct calls to functions
                 let terminator = bb_data.terminator();
                 if let TerminatorKind::Call {
-                    func: Operand::Constant(ref f), .. } = terminator.kind {
-                        if let ty::FnDef(callee_def_id, substs) = f.ty.sty {
+                    func: ref op, .. } = terminator.kind {
+                        if let ty::FnDef(callee_def_id, substs) = op.ty(caller_mir, self.tcx).sty {
                             if let Some(instance) = Instance::resolve(self.tcx,
                                                                       param_env,
                                                                       callee_def_id,

src/test/mir-opt/inline-any-operand.rs

@@ -0,0 +1,39 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: -Z span_free_formats
+
+// Tests that MIR inliner works for any operand
+
+fn main() {
+    println!("{}", bar());
+}
+
+#[inline(always)]
+fn foo(x: i32, y: i32) -> bool {
+    x == y
+}
+
+fn bar() -> bool {
+    let f = foo;
+    f(1, -1)
+}
+
+// END RUST SOURCE
+// START rustc.bar.Inline.after.mir
+// ...
+// bb0: {
+//     ...
+//     _0 = Eq(move _3, move _4);
+//     ...
+//     return;
+// }
+// ...
+// END rustc.bar.Inline.after.mir