<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div>Hi Bill,</div><div><br></div><div>I’ve attached the measurement made on compile time for O3.</div><div>In that file, the Reference column is llvm r177120 without the proposed patch and Test is the same compiler with the proposed patch and constant merging enabled.</div><div>Both compilers have been generated without assertions and with optimizations (i.e., release mode).</div><div><br></div><div>The speedup column reports a ratio: Test/Reference, thus the bigger the better.</div><div><br></div><div>On average, the impact is limited (0.99 speedup, thus 1% slow-down). The maximum and minimum reported numbers are, in my opinion, not much relevant as the related tests (SingleSource/UnitTests/Vector/build and MultiSource/Benchmarks/MiBench/network-dijkstra/network-dijkstr) are compiled very quickly and the measurement method is not that accurate.</div><div>Moreover, we have to keep in mind that this patch adds a check for a currently bogus behavior with global variables maked as “used”.</div><div><br></div><div>Feel free to comment!</div><div><br></div><div>Thanks,</div><br><div apple-content-edited="true">
<div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">-Quentin</div>
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