1; RUN: llc -mcpu=pwr7 -O0 -fast-isel=false < %s | FileCheck %s 2 3; This tests correct handling of empty aggregate parameters and return values. 4; An empty parameter passed by value does not consume a protocol register or 5; a parameter save area doubleword. An empty parameter passed by reference 6; is treated as any other pointer parameter. An empty aggregate return value 7; is treated as any other aggregate return value, passed via address as a 8; hidden parameter in GPR3. In this example, GPR3 contains the return value 9; address, GPR4 contains the address of e2, and e1 and e3 are not passed or 10; received. 11 12target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64" 13target triple = "powerpc64-unknown-linux-gnu" 14 15%struct.empty = type {} 16 17define void @callee(%struct.empty* noalias sret %agg.result, %struct.empty* byval %a1, %struct.empty* %a2, %struct.empty* byval %a3) nounwind { 18entry: 19 %a2.addr = alloca %struct.empty*, align 8 20 store %struct.empty* %a2, %struct.empty** %a2.addr, align 8 21 %0 = load %struct.empty*, %struct.empty** %a2.addr, align 8 22 %1 = bitcast %struct.empty* %agg.result to i8* 23 %2 = bitcast %struct.empty* %0 to i8* 24 call void @llvm.memcpy.p0i8.p0i8.i64(i8* %1, i8* %2, i64 0, i32 1, i1 false) 25 ret void 26} 27 28; CHECK-LABEL: callee: 29; CHECK: std 4, 30; CHECK-NOT: std 5, 31; CHECK-NOT: std 6, 32; CHECK: blr 33 34declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind 35 36define void @caller(%struct.empty* noalias sret %agg.result) nounwind { 37entry: 38 %e1 = alloca %struct.empty, align 1 39 %e2 = alloca %struct.empty, align 1 40 %e3 = alloca %struct.empty, align 1 41 call void @callee(%struct.empty* sret %agg.result, %struct.empty* byval %e1, %struct.empty* %e2, %struct.empty* byval %e3) 42 ret void 43} 44 45; CHECK-LABEL: caller: 46; CHECK: addi 4, 47; CHECK-NOT: std 5, 48; CHECK-NOT: std 6, 49; CHECK: bl callee 50