Reserved.set(AVR::SPH);
Reserved.set(AVR::SP);
- // Reserve the frame pointer registers r28 and r29 if the function requires one.
- if (TFI->hasFP(MF)) {
- Reserved.set(AVR::R28);
- Reserved.set(AVR::R29);
- Reserved.set(AVR::R29R28);
- }
+ // We tenatively reserve the frame pointer register r29:r28 because the
+ // function may require one, but we cannot tell until register allocation
+ // is complete, which can be too late.
+ //
+ // Instead we just unconditionally reserve the Y register.
+ //
+ // TODO: Write a pass to enumerate functions which reserved the Y register
+ // but didn't end up needing a frame pointer. In these, we can
+ // convert one or two of the spills inside to use the Y register.
+ Reserved.set(AVR::R28);
+ Reserved.set(AVR::R29);
+ Reserved.set(AVR::R29R28);
return Reserved;
}
; SP restore
; CHECK: in r0, 63
; CHECK-NEXT: cli
-; CHECK-NEXT: out 62, r29
+; CHECK-NEXT: out 62, r7
; CHECK-NEXT: out 63, r0
-; CHECK-NEXT: out 61, r28
+; CHECK-NEXT: out 61, r6
%vla = alloca i16, i16 %x
call void @foo2(i16* %vla, i64 0, i64 0, i64 0)
ret void