Diego Novillo 62bfc25308 Fix information loss in branch probability computation. ... Summary: This addresses PR 22718. When branch weights are too large, they were being clamped to the range [1, MaxWeightForBB]. But this clamping is only applied to edges that go outside the range, so it distorts the relative branch probabilities. This patch changes the weight calculation to scale every branch so the relative probabilities are preserved. The scaling is done differently now. First, all the branch weights are added up, and if the sum exceeds 32 bits, it computes an integer scale to bring all the weights within the range. The patch fixes an existing test that had slightly wrong branch probabilities due to the previous clamping. It now gets branch weights scaled accordingly. Reviewers: dexonsmith Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D9442 llvm-svn: 236750		2015-05-07 17:22:06 +00:00
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basic.ll	Re-apply r234898 and fix tests.	2015-04-15 06:24:07 +00:00
loop.ll
noreturn.ll
pr18705.ll
pr22718.ll	Fix information loss in branch probability computation.	2015-05-07 17:22:06 +00:00