ignore simd temps

Author: tesuji

compiler/rustc_mir_transform/src/promote_consts_local_arrays.rs

@@ -76,7 +76,7 @@ impl<'tcx> MirPass<'tcx> for PromoteArraysOpt<'tcx> {
         if let Some(ctx) = tcx.hir().body_const_context(body.source.def_id()) {
             use hir::ConstContext::*;
             match ctx {
-                Static(_) | Const {inline: _ } => return,
+                Static(_) | Const { inline: _ } => return,
                 _ => {}
             }
         }
@@ -178,16 +178,29 @@ impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> {
 
     #[instrument(level = "debug", skip(self, rvalue))]
     fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
-        if !rvalue.ty(&self.ccx.body.local_decls, self.ccx.tcx).is_array() {
+        self.super_rvalue(rvalue, location);
+
+        let rvalue_ty = rvalue.ty(&self.ccx.body.local_decls, self.ccx.tcx);
+        if !rvalue_ty.is_array() {
             debug!(?rvalue);
         }
 
-        self.super_rvalue(rvalue, location);
-
-        let Rvalue::Aggregate(kind, _ops) = rvalue else {
+        let Rvalue::Aggregate(kind, operands) = rvalue else {
             return;
         };
 
+        if let ty::Adt(adt, _) = rvalue_ty.kind()
+            && adt.repr().simd()
+        {
+            debug!("ignore #[repr(simd)]");
+            if let Some(first) = operands.iter().next()
+                && let Operand::Copy(place) | Operand::Move(place) = first
+            {
+                self.temps[place.local] = TempState::Unpromotable;
+            }
+            return;
+        }
+
         debug!("pushing a candidate of type {:?} @ {:?}", kind, location);
         self.candidates.push(Candidate { location });
     }

tests/mir-opt/const_array_locals.rs

@@ -1,4 +1,8 @@
 //@ test-mir-pass: PromoteArraysOpt
+#![feature(repr_simd)]
+
+#[repr(simd)]
+struct F32x8([f32; 8]);
 
 // EMIT_MIR const_array_locals.main.PromoteArraysOpt.diff
 // CHECK-LABEL: fn main() -> () {
@@ -28,6 +32,8 @@ pub fn main() {
     consume([255, 105, 15, 39, 62, 251, 191, 178, 9, 4, 56, 221,
         193, 164, 194, 197, 6, 243, 218, 171, 87, 247, 104,
         159, 22, 157, 105, 31, 96, 173, 50, 1,]);
+
+    let _f = F32x8([1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0]);
 }
 
 fn consume(_arr: [u16; 32]) {