[llvm-dev] SystemZ intrinsics definitions / memory flags (original) (raw)
Jonas Paulsson via llvm-dev llvm-dev at lists.llvm.org
Thu Nov 30 03:11:56 PST 2017
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Hi,
I would like some help on how to change some SystemZ intrinsics (memory) flags that are wrong. Currently MIs are forced to have known wrong flags because they have an intrinsic in their pattern that demands the instruction to also have the same flag. The problem is that I couldn't figure out how to change the intrinsic flags...
- This intrinsic only stores and does not load:
def int_s390_tbegin : Intrinsic<[llvm_i32_ty], [llvm_ptr_ty, llvm_i32_ty], [IntrNoDuplicate]>;
let mayLoad = 1 in // WRONG: does not load def TBEGINC : SideEffectBinarySIL<"tbeginc", 0xE561, int_s390_tbeginc, imm32zx16>;
I tried doing [IntrNoDuplicate, WriteOnly<0>], but found that for some reason that didn't work as I had hoped for.
- Similarly,
def int_s390_ntstg : Intrinsic<[], [llvm_i64_ty, llvm_ptr64_ty], [IntrArgMemOnly]>;
does not load, but the using instruction must have the mayLoad flag set. Again, WriteOnly<1> does not work.
- This intrinsic:
def int_s390_tabort : Intrinsic<[], [llvm_i64_ty], [IntrNoReturn, Throws]>;
should have just the hasSideEffects=1 on the instruction, but per the above intrinsic definition, both mayLoad and mayStore flags are required on the MI.
- These two set/read the FP control register, and both have reg-reg/mem-reg variants. So EFPC and SFPC actually do not touch memory at all:
def int_s390_sfpc : GCCBuiltin<"__builtin_s390_sfpc">, Intrinsic<[], [llvm_i32_ty], []>; def int_s390_efpc : GCCBuiltin<"__builtin_s390_efpc">, Intrinsic<[llvm_i32_ty], [], []>;
let mayLoad = 1, mayStore = 1 in { def EFPC : InherentRRE<"efpc", 0xB38C, GR32, int_s390_efpc>; // no-mem def STFPC : StoreInherentS<"stfpc", 0xB29C, storei, 4>; // stores
def SFPC : SideEffectUnaryRRE<"sfpc", 0xB384, GR32, int_s390_sfpc>; // no-mem def LFPC : SideEffectUnaryS<"lfpc", 0xB29D, loadu, 4>;>; // loads }
Is the proper solution in this case to make a duplicate version for each intrinsic that does not touch memory?
Any suggestions welcome,
/Jonas
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