From 9835e2ae736235810b4ea1c162ca5e65c547e770 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sat, 18 May 2024 04:49:50 +0200
Subject: Merging upstream version 1.71.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 compiler/rustc_codegen_ssa/src/mir/operand.rs | 63 ++++++++++++++++++++-------
 1 file changed, 48 insertions(+), 15 deletions(-)

(limited to 'compiler/rustc_codegen_ssa/src/mir/operand.rs')

diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs
index b37797fef..2301c3ef1 100644
--- a/compiler/rustc_codegen_ssa/src/mir/operand.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs
@@ -2,6 +2,7 @@ use super::place::PlaceRef;
 use super::{FunctionCx, LocalRef};
 
 use crate::base;
+use crate::common::TypeKind;
 use crate::glue;
 use crate::traits::*;
 use crate::MemFlags;
@@ -236,19 +237,47 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
         };
 
         match (&mut val, field.abi) {
-            (OperandValue::Immediate(llval), _) => {
+            (
+                OperandValue::Immediate(llval),
+                Abi::Scalar(_) | Abi::ScalarPair(..) | Abi::Vector { .. },
+            ) => {
                 // Bools in union fields needs to be truncated.
                 *llval = bx.to_immediate(*llval, field);
                 // HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
-                *llval = bx.bitcast(*llval, bx.cx().immediate_backend_type(field));
+                let ty = bx.cx().immediate_backend_type(field);
+                if bx.type_kind(ty) == TypeKind::Pointer {
+                    *llval = bx.pointercast(*llval, ty);
+                }
             }
             (OperandValue::Pair(a, b), Abi::ScalarPair(a_abi, b_abi)) => {
                 // Bools in union fields needs to be truncated.
                 *a = bx.to_immediate_scalar(*a, a_abi);
                 *b = bx.to_immediate_scalar(*b, b_abi);
                 // HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
-                *a = bx.bitcast(*a, bx.cx().scalar_pair_element_backend_type(field, 0, true));
-                *b = bx.bitcast(*b, bx.cx().scalar_pair_element_backend_type(field, 1, true));
+                let a_ty = bx.cx().scalar_pair_element_backend_type(field, 0, true);
+                let b_ty = bx.cx().scalar_pair_element_backend_type(field, 1, true);
+                if bx.type_kind(a_ty) == TypeKind::Pointer {
+                    *a = bx.pointercast(*a, a_ty);
+                }
+                if bx.type_kind(b_ty) == TypeKind::Pointer {
+                    *b = bx.pointercast(*b, b_ty);
+                }
+            }
+            // Newtype vector of array, e.g. #[repr(simd)] struct S([i32; 4]);
+            (OperandValue::Immediate(llval), Abi::Aggregate { sized: true }) => {
+                assert!(matches!(self.layout.abi, Abi::Vector { .. }));
+
+                let llty = bx.cx().backend_type(self.layout);
+                let llfield_ty = bx.cx().backend_type(field);
+
+                // Can't bitcast an aggregate, so round trip through memory.
+                let lltemp = bx.alloca(llfield_ty, field.align.abi);
+                let llptr = bx.pointercast(lltemp, bx.cx().type_ptr_to(llty));
+                bx.store(*llval, llptr, field.align.abi);
+                *llval = bx.load(llfield_ty, lltemp, field.align.abi);
+            }
+            (OperandValue::Immediate(_), Abi::Uninhabited | Abi::Aggregate { sized: false }) => {
+                bug!()
             }
             (OperandValue::Pair(..), _) => bug!(),
             (OperandValue::Ref(..), _) => bug!(),
@@ -373,8 +402,6 @@ impl<'a, 'tcx, V: CodegenObject> OperandValue<V> {
         indirect_dest: PlaceRef<'tcx, V>,
     ) {
         debug!("OperandRef::store_unsized: operand={:?}, indirect_dest={:?}", self, indirect_dest);
-        let flags = MemFlags::empty();
-
         // `indirect_dest` must have `*mut T` type. We extract `T` out of it.
         let unsized_ty = indirect_dest
             .layout
@@ -387,17 +414,23 @@ impl<'a, 'tcx, V: CodegenObject> OperandValue<V> {
             bug!("store_unsized called with a sized value")
         };
 
-        // FIXME: choose an appropriate alignment, or use dynamic align somehow
-        let max_align = Align::from_bits(128).unwrap();
-        let min_align = Align::from_bits(8).unwrap();
-
-        // Allocate an appropriate region on the stack, and copy the value into it
-        let (llsize, _) = glue::size_and_align_of_dst(bx, unsized_ty, Some(llextra));
-        let lldst = bx.byte_array_alloca(llsize, max_align);
-        bx.memcpy(lldst, max_align, llptr, min_align, llsize, flags);
+        // Allocate an appropriate region on the stack, and copy the value into it. Since alloca
+        // doesn't support dynamic alignment, we allocate an extra align - 1 bytes, and align the
+        // pointer manually.
+        let (size, align) = glue::size_and_align_of_dst(bx, unsized_ty, Some(llextra));
+        let one = bx.const_usize(1);
+        let align_minus_1 = bx.sub(align, one);
+        let size_extra = bx.add(size, align_minus_1);
+        let min_align = Align::ONE;
+        let alloca = bx.byte_array_alloca(size_extra, min_align);
+        let address = bx.ptrtoint(alloca, bx.type_isize());
+        let neg_address = bx.neg(address);
+        let offset = bx.and(neg_address, align_minus_1);
+        let dst = bx.inbounds_gep(bx.type_i8(), alloca, &[offset]);
+        bx.memcpy(dst, min_align, llptr, min_align, size, MemFlags::empty());
 
         // Store the allocated region and the extra to the indirect place.
-        let indirect_operand = OperandValue::Pair(lldst, llextra);
+        let indirect_operand = OperandValue::Pair(dst, llextra);
         indirect_operand.store(bx, indirect_dest);
     }
 }
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