llvm dev - Sep 2011 - [LLVMdev] [LLVMDev] The ComputeHash algorithm in FoldingSet is unsafe

I use FoldingSet to save some data structures. And I found somehow it always
abandon a new node. I tracked the bug into the ComputeHash() function of
FoldingSet. It computes the SAME hash value for these two 32-bit unsigned
integer sequences:


size: 17
4144534024, 32767, 4146895704, 32767, 4027803688, 32767, 4026983736, 32767,
4147202696, 32767, 4026587256, 32767, 0, 4026589472, 32767, 0, 0,
size: 16
4030909168, 32767, 4028631392, 32767, 4029542384, 32767, 0, 4028487592, 32767,
4026587256, 32767, 0, 4026589472, 32767, 0, 0,


The hash value is 2111586599                                             


The test code is attached.


What should we do with it?
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