Lower the assume intrinsic to a MIR statement

Author: oli-obk

src/base.rs

@@ -791,6 +791,8 @@ fn codegen_stmt<'tcx>(
         | StatementKind::Nop
         | StatementKind::FakeRead(..)
         | StatementKind::Retag { .. }
+        // We ignore `assume` intrinsics, they are only useful for optimizations
+        | StatementKind::Assume(..)
         | StatementKind::AscribeUserType(..) => {}
 
         StatementKind::Coverage { .. } => fx.tcx.sess.fatal("-Zcoverage is unimplemented"),

src/constant.rs

@@ -540,6 +540,7 @@ pub(crate) fn mir_operand_get_const_val<'tcx>(
                             return None;
                         } // conservative handling
                         StatementKind::Assign(_)
+                        | StatementKind::Assume(_)
                         | StatementKind::FakeRead(_)
                         | StatementKind::SetDiscriminant { .. }
                         | StatementKind::Deinit(_)

src/intrinsics/mod.rs

@@ -357,9 +357,6 @@ fn codegen_regular_intrinsic_call<'tcx>(
     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 
     match intrinsic {
-        sym::assume => {
-            intrinsic_args!(fx, args => (_a); intrinsic);
-        }
         sym::likely | sym::unlikely => {
             intrinsic_args!(fx, args => (a); intrinsic);