Dev Builds » 20190129-1640

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Commit ID 3302349662f8c0b01946cd9d62ac087685c0c816
Author DU-jdto
Date 2019-01-29 16:40:00 UTC
Don't update pvHit after IID This patch removes line 875 of search.cpp, which was updating pvHit after IID. Bench testing at depth 22 shows that line 875 of search.cpp never changes the value of pvHit at NonPV nodes, while at PV nodes it often changes the value from true to false (and never the reverse). This is because the definition of pvHit at line 642 is : ``` pvHit = (ttHit && tte->pv_hit()) || (PvNode && depth > 4 * ONE_PLY); ``` while the assignment after IID omits the ` (PvNode && depth > 4 * ONE_PLY) ` condition. As such, unlike the other two post-IID tte reads, this line of code does not make SF's state more consistent, but rather introduces an inconsistency in the definition of pvHit. Indeed, changing line 875 read ``` pvHit = (ttHit && tte->pv_hit()) || (PvNode && depth > 4 * ONE_PLY); ``` to match line 642 is functionally equivalent to removing the line entirely, as this patch does. STC LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 62756 W: 13787 L: 13746 D: 35223 LTC LLR: 3.19 (-2.94,2.94) [-3.00,1.00] Total: 61900 W: 10179 L: 10111 D: 41610 Bench: 3796134
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