parent
3246eaec90
commit
20618d0e42
@ -169,6 +169,11 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
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operand: OperandRef<'tcx>)
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{
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debug!("store_operand: operand={}", operand.repr(bcx));
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// Avoid generating stores of zero-sized values, because the only way to have a zero-sized
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// value is through `undef`, and store itself is useless.
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if common::type_is_zero_size(bcx.ccx(), operand.ty) {
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return;
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}
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match operand.val {
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OperandValue::Ref(r) => base::memcpy_ty(bcx, lldest, r, operand.ty),
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OperandValue::Immediate(s) => base::store_ty(bcx, s, lldest, operand.ty),
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@ -108,11 +108,15 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
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},
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_ => {
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for (i, operand) in operands.iter().enumerate() {
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// Note: perhaps this should be StructGep, but
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// note that in some cases the values here will
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// not be structs but arrays.
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let lldest_i = build::GEPi(bcx, dest.llval, &[0, i]);
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self.trans_operand_into(bcx, lldest_i, operand);
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let op = self.trans_operand(bcx, operand);
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// Do not generate stores and GEPis for zero-sized fields.
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if !common::type_is_zero_size(bcx.ccx(), op.ty) {
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// Note: perhaps this should be StructGep, but
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// note that in some cases the values here will
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// not be structs but arrays.
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let dest = build::GEPi(bcx, dest.llval, &[0, i]);
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self.store_operand(bcx, dest, op);
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}
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}
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}
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}
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27
src/test/codegen/mir_zst_stores.rs
Normal file
27
src/test/codegen/mir_zst_stores.rs
Normal file
@ -0,0 +1,27 @@
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// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// compile-flags: -C no-prepopulate-passes
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#![feature(rustc_attrs)]
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#![crate_type = "lib"]
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use std::marker::PhantomData;
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struct Zst { phantom: PhantomData<Zst> }
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// CHECK-LABEL: @mir
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#[no_mangle]
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#[rustc_mir]
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fn mir(){
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// CHECK-NOT: getelementptr
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// CHECK-NOT: store{{.*}}undef
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let x = Zst { phantom: PhantomData };
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}
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