Do not unnecessarily eval consts in codegen

Author: compiler-errors

compiler/rustc_codegen_cranelift/src/base.rs

@@ -785,8 +785,10 @@ fn codegen_stmt<'tcx>(
                 }
                 Rvalue::Repeat(ref operand, times) => {
                     let operand = codegen_operand(fx, operand);
-                    let times =
-                        fx.monomorphize(times).eval_target_usize(fx.tcx, ParamEnv::reveal_all());
+                    let times = fx
+                        .monomorphize(times)
+                        .try_to_target_usize(fx.tcx)
+                        .expect("expected monomorphic const in codegen");
                     if operand.layout().size.bytes() == 0 {
                         // Do nothing for ZST's
                     } else if fx.clif_type(operand.layout().ty) == Some(types::I8) {
@@ -944,7 +946,10 @@ fn codegen_stmt<'tcx>(
 fn codegen_array_len<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, place: CPlace<'tcx>) -> Value {
     match *place.layout().ty.kind() {
         ty::Array(_elem_ty, len) => {
-            let len = fx.monomorphize(len).eval_target_usize(fx.tcx, ParamEnv::reveal_all()) as i64;
+            let len = fx
+                .monomorphize(len)
+                .try_to_target_usize(fx.tcx)
+                .expect("expected monomorphic const in codegen") as i64;
             fx.bcx.ins().iconst(fx.pointer_type, len)
         }
         ty::Slice(_elem_ty) => place.to_ptr_unsized().1,

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -77,9 +77,7 @@ pub(crate) fn eval_mir_constant<'tcx>(
 ) -> (ConstValue<'tcx>, Ty<'tcx>) {
     let cv = fx.monomorphize(constant.const_);
     // This cannot fail because we checked all required_consts in advance.
-    let val = cv
-        .eval(fx.tcx, ty::ParamEnv::reveal_all(), constant.span)
-        .expect("erroneous constant missed by mono item collection");
+    let val = cv.try_to_valtree(fx.tcx).expect("erroneous constant missed by mono item collection");
     (val, cv.ty())
 }
 

compiler/rustc_codegen_cranelift/src/debuginfo/types.rs

@@ -44,7 +44,7 @@ impl DebugContext {
                 type_dbg,
                 ty,
                 *elem_ty,
-                len.eval_target_usize(tcx, ty::ParamEnv::reveal_all()),
+                len.try_to_target_usize(tcx).expect("expected monomorphic const in codegen"),
             ),
             // ty::Slice(_) | ty::Str
             // ty::Dynamic

compiler/rustc_codegen_cranelift/src/inline_asm.rs

@@ -231,7 +231,7 @@ pub(crate) fn codegen_naked_asm<'tcx>(
                     ty::EarlyBinder::bind(value.const_),
                 );
                 let const_value = cv
-                    .eval(tcx, ty::ParamEnv::reveal_all(), value.span)
+                    .try_to_valtree(tcx)
                     .expect("erroneous constant missed by mono item collection");
 
                 let value = rustc_codegen_ssa::common::asm_const_to_str(

compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs

@@ -131,8 +131,8 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
 
             let idx = generic_args[2]
                 .expect_const()
-                .eval(fx.tcx, ty::ParamEnv::reveal_all(), span)
-                .unwrap()
+                .try_to_valtree(tcx)
+                .expect("expected monomorphic const in codegen")
                 .1
                 .unwrap_branch();
 

compiler/rustc_codegen_cranelift/src/unsize.rs

@@ -24,10 +24,10 @@ pub(crate) fn unsized_info<'tcx>(
     let (source, target) =
         fx.tcx.struct_lockstep_tails_for_codegen(source, target, ParamEnv::reveal_all());
     match (&source.kind(), &target.kind()) {
-        (&ty::Array(_, len), &ty::Slice(_)) => fx
-            .bcx
-            .ins()
-            .iconst(fx.pointer_type, len.eval_target_usize(fx.tcx, ParamEnv::reveal_all()) as i64),
+        (&ty::Array(_, len), &ty::Slice(_)) => fx.bcx.ins().iconst(
+            fx.pointer_type,
+            len.try_to_target_usize(fx.tcx).expect("expected monomorphic const in codegen") as i64,
+        ),
         (&ty::Dynamic(data_a, _, src_dyn_kind), &ty::Dynamic(data_b, _, target_dyn_kind))
             if src_dyn_kind == target_dyn_kind =>
         {

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -125,7 +125,9 @@ fn build_fixed_size_array_di_node<'ll, 'tcx>(
 
     let (size, align) = cx.size_and_align_of(array_type);
 
-    let upper_bound = len.eval_target_usize(cx.tcx, ty::ParamEnv::reveal_all()) as c_longlong;
+    let upper_bound = len
+        .try_to_target_usize(cx.tcx)
+        .expect("expected monomorphic const in codegen") as c_longlong;
 
     let subrange =
         unsafe { Some(llvm::LLVMRustDIBuilderGetOrCreateSubrange(DIB(cx), 0, upper_bound)) };

compiler/rustc_codegen_ssa/src/base.rs

@@ -115,9 +115,9 @@ fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     let (source, target) =
         cx.tcx().struct_lockstep_tails_for_codegen(source, target, bx.param_env());
     match (source.kind(), target.kind()) {
-        (&ty::Array(_, len), &ty::Slice(_)) => {
-            cx.const_usize(len.eval_target_usize(cx.tcx(), ty::ParamEnv::reveal_all()))
-        }
+        (&ty::Array(_, len), &ty::Slice(_)) => cx.const_usize(
+            len.try_to_target_usize(cx.tcx()).expect("expected monomorphic const in codegen"),
+        ),
         (&ty::Dynamic(data_a, _, src_dyn_kind), &ty::Dynamic(data_b, _, target_dyn_kind))
             if src_dyn_kind == target_dyn_kind =>
         {

compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs

@@ -188,7 +188,8 @@ fn push_debuginfo_type_name<'tcx>(
                     _ => write!(
                         output,
                         ",{}>",
-                        len.eval_target_usize(tcx, ty::ParamEnv::reveal_all())
+                        len.try_to_target_usize(tcx)
+                            .expect("expected monomorphic const in codegen")
                     )
                     .unwrap(),
                 }
@@ -200,7 +201,8 @@ fn push_debuginfo_type_name<'tcx>(
                     _ => write!(
                         output,
                         "; {}]",
-                        len.eval_target_usize(tcx, ty::ParamEnv::reveal_all())
+                        len.try_to_target_usize(tcx)
+                            .expect("expected monomorphic const in codegen")
                     )
                     .unwrap(),
                 }

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -114,7 +114,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
                 let count = self
                     .monomorphize(count)
-                    .eval_target_usize(bx.cx().tcx(), ty::ParamEnv::reveal_all());
+                    .try_to_target_usize(bx.tcx())
+                    .expect("expected monomorphic const in codegen");
 
                 bx.write_operand_repeatedly(cg_elem, count, dest);
             }
@@ -803,7 +804,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         if let Some(index) = place.as_local() {
             if let LocalRef::Operand(op) = self.locals[index] {
                 if let ty::Array(_, n) = op.layout.ty.kind() {
-                    let n = n.eval_target_usize(bx.cx().tcx(), ty::ParamEnv::reveal_all());
+                    let n = n
+                        .try_to_target_usize(bx.tcx())
+                        .expect("expected monomorphic const in codegen");
                     return bx.cx().const_usize(n);
                 }
             }