rustc_codegen_ssa: flatten nested ifs

Author: yotamofek

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -1537,8 +1537,9 @@ fn start_executing_work<B: ExtraBackendMethods>(
             // Spin up what work we can, only doing this while we've got available
             // parallelism slots and work left to spawn.
             if codegen_state != Aborted {
-                while !work_items.is_empty() && running_with_own_token < tokens.len() {
-                    let (item, _) = work_items.pop().unwrap();
+                while running_with_own_token < tokens.len()
+                    && let Some((item, _)) = work_items.pop()
+                {
                     spawn_work(
                         &cgcx,
                         &mut llvm_start_time,

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -656,25 +656,20 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
     // llvm/llvm-project#70563).
     if !codegen_fn_attrs.target_features.is_empty()
         && matches!(codegen_fn_attrs.inline, InlineAttr::Always)
+        && let Some(span) = inline_span
     {
-        if let Some(span) = inline_span {
-            tcx.dcx().span_err(span, "cannot use `#[inline(always)]` with `#[target_feature]`");
-        }
+        tcx.dcx().span_err(span, "cannot use `#[inline(always)]` with `#[target_feature]`");
     }
 
-    if !codegen_fn_attrs.no_sanitize.is_empty() && codegen_fn_attrs.inline.always() {
-        if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) {
-            let hir_id = tcx.local_def_id_to_hir_id(did);
-            tcx.node_span_lint(
-                lint::builtin::INLINE_NO_SANITIZE,
-                hir_id,
-                no_sanitize_span,
-                |lint| {
-                    lint.primary_message("`no_sanitize` will have no effect after inlining");
-                    lint.span_note(inline_span, "inlining requested here");
-                },
-            )
-        }
+    if !codegen_fn_attrs.no_sanitize.is_empty()
+        && codegen_fn_attrs.inline.always()
+        && let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span)
+    {
+        let hir_id = tcx.local_def_id_to_hir_id(did);
+        tcx.node_span_lint(lint::builtin::INLINE_NO_SANITIZE, hir_id, no_sanitize_span, |lint| {
+            lint.primary_message("`no_sanitize` will have no effect after inlining");
+            lint.span_note(inline_span, "inlining requested here");
+        })
     }
 
     // Weak lang items have the same semantics as "std internal" symbols in the
@@ -704,10 +699,10 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
     // Any linkage to LLVM intrinsics for now forcibly marks them all as never
     // unwinds since LLVM sometimes can't handle codegen which `invoke`s
     // intrinsic functions.
-    if let Some(name) = &codegen_fn_attrs.link_name {
-        if name.as_str().starts_with("llvm.") {
-            codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND;
-        }
+    if let Some(name) = &codegen_fn_attrs.link_name
+        && name.as_str().starts_with("llvm.")
+    {
+        codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND;
     }
 
     if let Some(features) = check_tied_features(

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -990,8 +990,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         });
 
         // Split the rust-call tupled arguments off.
-        let (first_args, untuple) = if abi == ExternAbi::RustCall && !args.is_empty() {
-            let (tup, args) = args.split_last().unwrap();
+        let (first_args, untuple) = if abi == ExternAbi::RustCall
+            && let Some((tup, args)) = args.split_last()
+        {
             (args, Some(tup))
         } else {
             (args, None)