1; RUN: opt < %s -deadargelim -S | FileCheck %s 2 3%Ty = type { i32, i32 } 4 5; sanity check that the argument and return value are both dead 6; CHECK-LABEL: define internal void @test1() 7 8define internal %Ty* @test1(%Ty* %this) { 9 ret %Ty* %this 10} 11 12; do not keep alive the return value of a function with a dead 'returned' argument 13; CHECK-LABEL: define internal void @test2() 14 15define internal %Ty* @test2(%Ty* returned %this) { 16 ret %Ty* %this 17} 18 19; dummy to keep 'this' alive 20@dummy = global %Ty* null 21 22; sanity check that return value is dead 23; CHECK-LABEL: define internal void @test3(%Ty* %this) 24 25define internal %Ty* @test3(%Ty* %this) { 26 store volatile %Ty* %this, %Ty** @dummy 27 ret %Ty* %this 28} 29 30; keep alive return value of a function if the 'returned' argument is live 31; CHECK-LABEL: define internal %Ty* @test4(%Ty* returned %this) 32 33define internal %Ty* @test4(%Ty* returned %this) { 34 store volatile %Ty* %this, %Ty** @dummy 35 ret %Ty* %this 36} 37 38; don't do this if 'returned' is on the call site... 39; CHECK-LABEL: define internal void @test5(%Ty* %this) 40 41define internal %Ty* @test5(%Ty* %this) { 42 store volatile %Ty* %this, %Ty** @dummy 43 ret %Ty* %this 44} 45 46define %Ty* @caller(%Ty* %this) { 47 %1 = call %Ty* @test1(%Ty* %this) 48 %2 = call %Ty* @test2(%Ty* %this) 49 %3 = call %Ty* @test3(%Ty* %this) 50 %4 = call %Ty* @test4(%Ty* %this) 51; ...instead, drop 'returned' form the call site 52; CHECK: call void @test5(%Ty* %this) 53 %5 = call %Ty* @test5(%Ty* returned %this) 54 ret %Ty* %this 55} 56