Ignore intrinsic calls in cross-crate-inlining cost model

Author: saethlin

compiler/rustc_mir_transform/src/cross_crate_inline.rs

@@ -135,7 +135,12 @@ impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> {
                     }
                 }
             }
-            TerminatorKind::Call { unwind, .. } => {
+            TerminatorKind::Call { ref func, unwind, .. } => {
+                if let Some((fn_def_id, _)) = func.const_fn_def() {
+                    if self.tcx.has_attr(fn_def_id, sym::rustc_intrinsic) {
+                        return;
+                    }
+                }
                 self.calls += 1;
                 if let UnwindAction::Cleanup(_) = unwind {
                     self.landing_pads += 1;

tests/assembly-llvm/breakpoint.rs

@@ -9,6 +9,7 @@
 // CHECK-LABEL: use_bp
 // aarch64: brk #0xf000
 // x86_64: int3
+#[inline(never)]
 pub fn use_bp() {
     core::arch::breakpoint();
 }

tests/assembly-llvm/simd/reduce-fadd-unordered.rs

@@ -16,6 +16,7 @@ use std::simd::*;
 // It would emit about an extra fadd, depending on the architecture.
 
 // CHECK-LABEL: reduce_fadd_negative_zero
+#[inline(never)]
 pub unsafe fn reduce_fadd_negative_zero(v: f32x4) -> f32 {
     // x86_64: addps
     // x86_64-NEXT: movshdup

tests/codegen-llvm/default-visibility.rs

@@ -32,6 +32,7 @@ pub static tested_symbol: [u8; 6] = *b"foobar";
 // INTERPOSABLE: @{{.*}}default_visibility{{.*}}tested_symbol{{.*}} = constant
 // DEFAULT:      @{{.*}}default_visibility{{.*}}tested_symbol{{.*}} = constant
 
+#[inline(never)]
 pub fn do_memcmp(left: &[u8], right: &[u8]) -> i32 {
     left.cmp(right) as i32
 }