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Remove unnecessary temporaries from compare_values()

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This commit is contained in:
Björn Steinbrink 2015-08-25 13:49:02 +02:00
parent 1806174ab4
commit 6e60fdba17
1 changed files with 22 additions and 18 deletions
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40
src/librustc_trans/trans/_match.rs
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@ -875,8 +875,10 @@ fn compare_values<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
debug_loc: DebugLoc)
-> Result<'blk, 'tcx> {
fn compare_str<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
lhs: ValueRef,
rhs: ValueRef,
lhs_data: ValueRef,
lhs_len: ValueRef,
rhs_data: ValueRef,
rhs_len: ValueRef,
rhs_t: Ty<'tcx>,
debug_loc: DebugLoc)
-> Result<'blk, 'tcx> {
@ -884,10 +886,6 @@ fn compare_values<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
None,
&format!("comparison of `{}`", rhs_t),
StrEqFnLangItem);
let lhs_data = Load(cx, expr::get_dataptr(cx, lhs));
let lhs_len = Load(cx, expr::get_meta(cx, lhs));
let rhs_data = Load(cx, expr::get_dataptr(cx, rhs));
let rhs_len = Load(cx, expr::get_meta(cx, rhs));
callee::trans_lang_call(cx, did, &[lhs_data, lhs_len, rhs_data, rhs_len], None, debug_loc)
}
@ -899,7 +897,13 @@ fn compare_values<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
match rhs_t.sty {
ty::TyRef(_, mt) => match mt.ty.sty {
ty::TyStr => compare_str(cx, lhs, rhs, rhs_t, debug_loc),
ty::TyStr => {
let lhs_data = Load(cx, expr::get_dataptr(cx, lhs));
let lhs_len = Load(cx, expr::get_meta(cx, lhs));
let rhs_data = Load(cx, expr::get_dataptr(cx, rhs));
let rhs_len = Load(cx, expr::get_meta(cx, rhs));
compare_str(cx, lhs_data, lhs_len, rhs_data, rhs_len, rhs_t, debug_loc)
}
ty::TyArray(ty, _) | ty::TySlice(ty) => match ty.sty {
ty::TyUint(ast::TyU8) => {
// NOTE: cast &[u8] and &[u8; N] to &str and abuse the str_eq lang item,
@ -907,24 +911,24 @@ fn compare_values<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
let pat_len = val_ty(rhs).element_type().array_length();
let ty_str_slice = cx.tcx().mk_static_str();
let rhs_str = alloc_ty(cx, ty_str_slice, "rhs_str");
Store(cx, expr::get_dataptr(cx, rhs), expr::get_dataptr(cx, rhs_str));
Store(cx, C_uint(cx.ccx(), pat_len), expr::get_meta(cx, rhs_str));
let rhs_data = GEPi(cx, rhs, &[0, 0]);
let rhs_len = C_uint(cx.ccx(), pat_len);
let lhs_str;
let lhs_data;
let lhs_len;
if val_ty(lhs) == val_ty(rhs) {
// Both the discriminant and the pattern are thin pointers
lhs_str = alloc_ty(cx, ty_str_slice, "lhs_str");
Store(cx, expr::get_dataptr(cx, lhs), expr::get_dataptr(cx, lhs_str));
Store(cx, C_uint(cx.ccx(), pat_len), expr::get_meta(cx, lhs_str));
}
else {
lhs_data = GEPi(cx, lhs, &[0, 0]);
lhs_len = C_uint(cx.ccx(), pat_len);
} else {
// The discriminant is a fat pointer
let llty_str_slice = type_of::type_of(cx.ccx(), ty_str_slice).ptr_to();
lhs_str = PointerCast(cx, lhs, llty_str_slice);
let lhs_str = PointerCast(cx, lhs, llty_str_slice);
lhs_data = Load(cx, expr::get_dataptr(cx, lhs_str));
lhs_len = Load(cx, expr::get_meta(cx, lhs_str));
}
compare_str(cx, lhs_str, rhs_str, rhs_t, debug_loc)
compare_str(cx, lhs_data, lhs_len, rhs_data, rhs_len, rhs_t, debug_loc)
},
_ => cx.sess().bug("only byte strings supported in compare_values"),
},