[PATCH] D141189: [Mips] Set setMaxAtomicSizeInBitsSupported

[YunQiang Su via Phabricator via llvm-commits]

wzssyqa added inline comments.


================
Comment at: llvm/lib/Target/Mips/MipsISelLowering.cpp:500-501
+    setMaxAtomicSizeInBitsSupported(32);
+  else
+    setMaxAtomicSizeInBitsSupported(0);
+
----------------
brad wrote:
> arsenm wrote:
> > Else case doesn't make sense to me but I know nothing about mips 
> > Else case doesn't make sense to me but I know nothing about mips 
> 
> To deal with MIPS-I not having support for atomics.
Sorry for me. I am no idea about what's the mean of the value of `setMaxAtomicSizeInBitsSupported`.

Maybe:
1) load/store instructions no quirky behavior: an instruction can be split to in result.
    If so, MIPS has never this problem since MIPS I.
2) normal load/store instructions can make sure that the data sync in a multicore system.
    If so, MIPS never archives this.
3) architecture has some instructions to help atomic ops.
    If so, MIPS has LL/SC since MIPS II.


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D141189/new/

https://reviews.llvm.org/D141189