[PATCH] D71589: [PowerPC] Adding a match pattern to recognize the and mask with RLWINM8

[qshanz via Phabricator via llvm-commits]

steven.zhang marked an inline comment as done.
steven.zhang added inline comments.


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Comment at: llvm/lib/Target/PowerPC/PPCInstrInfo.td:385
+    uint64_t Mask = (uint64_t)N->getZExtValue();
+    return isUInt<32>(Mask) && isRunOfOnes((unsigned)Mask, mb, me);
+  }
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lkail wrote:
> steven.zhang wrote:
> > shchenz wrote:
> > > we can only return true  when mb is not bigger than me.  and mask can be 0XF000000F, it becomes to  0XFFFFFFFFF000000F in rlwinm,then we get a 64bit value. This is wrong. 
> > Good point. And yes, this is the problem.
> Do we have to check `Mask & 0xffffffff00000000 == 0`?
No, it has been checked by isUInt<32>(Mask). However, I am planing to abandon this patch to post a completely patch that fix all the "and mask" issue llvm powerpc have.


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  https://reviews.llvm.org/D71589/new/

https://reviews.llvm.org/D71589