authorgravatar for joachim.schmidt557@outlook.comJoachim Schmidt <joachim.schmidt557@outlook.com> 2022-02-05 12:44:32+01:00
committergravatar for kubkon@jakubkonka.comJakub Konka <kubkon@jakubkonka.com> 2022-02-05 15:58:46+01:00
logd4c3475f3dce8ecf81ba2baaf97b6d25426919ec
tree887b11ac9d5103e3e7bb8f0d85a21e561d61472f
parentf2a82bafae414e9b454b77f6d0bcf768cfa9089b

stage2 ARM: clarify usage of unfreezeRegs in airSliceElemVal

1 files changed, 5 insertions(+), 7 deletions(-)

src/arch/arm/CodeGen.zig+5-7
......@@ -1247,7 +1247,6 @@ fn airSliceElemVal(self: *Self, inst: Air.Inst.Index) !void {
12471247 else => return self.fail("TODO slice_elem_val when slice is {}", .{slice_mcv}),
12481248 };
12491249 self.register_manager.freezeRegs(&.{base_mcv.register});
1250 defer self.register_manager.unfreezeRegs(&.{base_mcv.register});
12511250
12521251 switch (elem_size) {
12531252 1, 4 => {
......@@ -1283,6 +1282,8 @@ fn airSliceElemVal(self: *Self, inst: Air.Inst.Index) !void {
12831282 } },
12841283 });
12851284
1285 self.register_manager.unfreezeRegs(&.{base_mcv.register});
1286
12861287 break :result dst_mcv;
12871288 },
12881289 else => {
......@@ -1291,7 +1292,6 @@ fn airSliceElemVal(self: *Self, inst: Air.Inst.Index) !void {
12911292 const offset_mcv = try self.genArmMulConstant(bin_op.rhs, @intCast(u32, elem_size));
12921293 assert(offset_mcv == .register); // result of multiplication should always be register
12931294 self.register_manager.freezeRegs(&.{offset_mcv.register});
1294 defer self.register_manager.unfreezeRegs(&.{offset_mcv.register});
12951295
12961296 const addr_reg = try self.register_manager.allocReg(null);
12971297 self.register_manager.freezeRegs(&.{addr_reg});
......@@ -1299,11 +1299,9 @@ fn airSliceElemVal(self: *Self, inst: Air.Inst.Index) !void {
12991299
13001300 try self.genArmBinOpCode(addr_reg, base_mcv, offset_mcv, false, .add, .unsigned);
13011301
1302 // I know we will unfreeze these registers at the end of
1303 // the scope of :result. However, at this point in time,
1304 // neither the base register nor the offset register
1305 // contains any valuable data anymore. In order to reduce
1306 // register pressure, unfreeze them prematurely
1302 // At this point in time, neither the base register
1303 // nor the offset register contains any valuable data
1304 // anymore.
13071305 self.register_manager.unfreezeRegs(&.{ base_mcv.register, offset_mcv.register });
13081306
13091307 try self.load(dst_mcv, .{ .register = addr_reg }, slice_ptr_field_type);