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CBE: minor optimizations to output source

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mlugg 2023-04-25 04:49:47 +01:00
parent 295b8ca467
commit 2e23ddbe7b
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GPG Key ID: 58978E823BDE3EF9
1 changed files with 25 additions and 4 deletions
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29
src/codegen/c.zig
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@ -4291,9 +4291,13 @@ fn airBlock(f: *Function, inst: Air.Inst.Index) !CValue {
}
try f.object.indent_writer.insertNewline();
// label might be unused, add a dummy goto
// label must be followed by an expression, add an empty one.
try writer.print("goto zig_block_{d};\nzig_block_{d}: (void)0;\n", .{ block_id, block_id });
// noreturn blocks have no `br` instructions reaching them, so we don't want a label
if (!f.air.typeOfIndex(inst).isNoReturn()) {
// label must be followed by an expression, include an empty one.
try writer.print("zig_block_{d}:;\n", .{block_id});
}
return result;
}
@ -4345,7 +4349,7 @@ fn lowerTry(
else
try f.writeCValueMember(writer, err_union, .{ .identifier = "error" });
}
try writer.writeByte(')');
try writer.writeAll(") ");
try genBodyResolveState(f, inst, liveness_condbr.else_deaths, body, false);
try f.object.indent_writer.insertNewline();
@ -4417,7 +4421,11 @@ fn airBitcast(f: *Function, inst: Air.Inst.Index) !CValue {
const local = try f.allocLocal(inst, dest_ty);
// If the assignment looks like 'x = x', we don't need it
const can_elide = operand == .local and operand.local == local.new_local;
if (operand_ty.isAbiInt() and dest_ty.isAbiInt()) {
if (can_elide) return local;
const src_info = dest_ty.intInfo(target);
const dest_info = operand_ty.intInfo(target);
if (src_info.signedness == dest_info.signedness and
@ -4432,6 +4440,7 @@ fn airBitcast(f: *Function, inst: Air.Inst.Index) !CValue {
}
if (dest_ty.isPtrAtRuntime() and operand_ty.isPtrAtRuntime()) {
if (can_elide) return local;
try f.writeCValue(writer, local, .Other);
try writer.writeAll(" = (");
try f.renderType(writer, dest_ty);
@ -5463,6 +5472,12 @@ fn airUnwrapErrUnionErr(f: *Function, inst: Air.Inst.Index) !CValue {
const error_ty = error_union_ty.errorUnionSet();
const payload_ty = error_union_ty.errorUnionPayload();
const local = try f.allocLocal(inst, inst_ty);
if (!payload_ty.hasRuntimeBits() and operand == .local and operand.local == local.new_local) {
// The store will be 'x = x'; elide it.
return local;
}
const writer = f.object.writer();
try f.writeCValue(writer, local, .Other);
try writer.writeAll(" = ");
@ -5560,6 +5575,12 @@ fn airWrapErrUnionErr(f: *Function, inst: Air.Inst.Index) !CValue {
const writer = f.object.writer();
const local = try f.allocLocal(inst, inst_ty);
if (repr_is_err and err == .local and err.local == local.new_local) {
// The store will be 'x = x'; elide it.
return local;
}
if (!repr_is_err) {
const a = try Assignment.start(f, writer, payload_ty);
try f.writeCValueMember(writer, local, .{ .identifier = "payload" });