use llvm::{self, ValueRef};
use rustc::ty::{self, Ty};
use rustc::ty::cast::{CastTy, IntTy};
-use rustc::ty::layout::{Layout, LayoutTyper};
+use rustc::ty::layout::{self, Layout, LayoutTyper, Primitive};
use rustc::mir::tcx::LvalueTy;
use rustc::mir;
use rustc::middle::lang_items::ExchangeMallocFnLangItem;
use builder::Builder;
use callee;
use common::{self, val_ty, C_bool, C_null, C_uint};
-use common::{C_integral};
+use common::{C_integral, C_i32};
use adt;
use machine;
use monomorphize;
}
mir::Rvalue::Repeat(ref elem, ref count) => {
+ let dest_ty = dest.ty.to_ty(bcx.tcx());
+
+ // No need to inizialize memory of a zero-sized slice
+ if common::type_is_zero_size(bcx.ccx, dest_ty) {
+ return bcx;
+ }
+
let tr_elem = self.trans_operand(&bcx, elem);
let size = count.as_u64(bcx.tcx().sess.target.uint_type);
let size = C_uint(bcx.ccx, size);
let base = base::get_dataptr(&bcx, dest.llval);
+ let align = dest.alignment.to_align();
+
+ if let OperandValue::Immediate(v) = tr_elem.val {
+ if common::is_const_integral(v) && common::const_to_uint(v) == 0 {
+ let align = align.unwrap_or_else(|| bcx.ccx.align_of(tr_elem.ty));
+ let align = C_i32(bcx.ccx, align as i32);
+ let ty = type_of::type_of(bcx.ccx, dest_ty);
+ let size = machine::llsize_of(bcx.ccx, ty);
+ let fill = C_integral(Type::i8(bcx.ccx), 0, false);
+ base::call_memset(&bcx, base, fill, size, align, false);
+ return bcx;
+ }
+ }
+
+ // Use llvm.memset.p0i8.* to initialize byte arrays
+ let elem_layout = bcx.ccx.layout_of(tr_elem.ty).layout;
+ match *elem_layout {
+ Layout::Scalar { value: Primitive::Int(layout::I8), .. } |
+ Layout::CEnum { discr: layout::I8, .. } => {
+ let align = align.unwrap_or_else(|| bcx.ccx.align_of(tr_elem.ty));
+ let align = C_i32(bcx.ccx, align as i32);
+ let fill = tr_elem.immediate();
+ base::call_memset(&bcx, base, fill, size, align, false);
+ return bcx;
+ }
+ _ => ()
+ }
+
tvec::slice_for_each(&bcx, base, tr_elem.ty, size, |bcx, llslot, loop_bb| {
- self.store_operand(bcx, llslot, dest.alignment.to_align(), tr_elem);
+ self.store_operand(bcx, llslot, align, tr_elem);
bcx.br(loop_bb);
})
}
--- /dev/null
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: -C no-prepopulate-passes
+
+#![crate_type = "lib"]
+
+// CHECK-LABEL: @zero_sized_elem
+#[no_mangle]
+pub fn zero_sized_elem() {
+ // CHECK-NOT: br label %slice_loop_header{{.*}}
+ // CHECK-NOT: call void @llvm.memset.p0i8
+ let x = [(); 4];
+ drop(&x);
+}
+
+// CHECK-LABEL: @zero_len_array
+#[no_mangle]
+pub fn zero_len_array() {
+ // CHECK-NOT: br label %slice_loop_header{{.*}}
+ // CHECK-NOT: call void @llvm.memset.p0i8
+ let x = [4; 0];
+ drop(&x);
+}
+
+// CHECK-LABEL: @byte_array
+#[no_mangle]
+pub fn byte_array() {
+ // CHECK: call void @llvm.memset.p0i8.i{{[0-9]+}}(i8* {{.*}}, i8 7, i64 4
+ // CHECK-NOT: br label %slice_loop_header{{.*}}
+ let x = [7u8; 4];
+ drop(&x);
+}
+
+#[allow(dead_code)]
+#[derive(Copy, Clone)]
+enum Init {
+ Loop,
+ Memset,
+}
+
+// CHECK-LABEL: @byte_enum_array
+#[no_mangle]
+pub fn byte_enum_array() {
+ // CHECK: call void @llvm.memset.p0i8.i{{[0-9]+}}(i8* {{.*}}, i8 {{.*}}, i64 4
+ // CHECK-NOT: br label %slice_loop_header{{.*}}
+ let x = [Init::Memset; 4];
+ drop(&x);
+}
+
+// CHECK-LABEL: @zeroed_integer_array
+#[no_mangle]
+pub fn zeroed_integer_array() {
+ // CHECK: call void @llvm.memset.p0i8.i{{[0-9]+}}(i8* {{.*}}, i8 0, i64 16
+ // CHECK-NOT: br label %slice_loop_header{{.*}}
+ let x = [0u32; 4];
+ drop(&x);
+}
+
+// CHECK-LABEL: @nonzero_integer_array
+#[no_mangle]
+pub fn nonzero_integer_array() {
+ // CHECK: br label %slice_loop_header{{.*}}
+ // CHECK-NOT: call void @llvm.memset.p0i8
+ let x = [0x1a_2b_3c_4d_u32; 4];
+ drop(&x);
+}