search for: r172868

Nadav, We see multiple regressions after r172868 in ISPC compiler (based on LLVM optimizer). The regressions are due to spill/reloads, which are due to increase register pressure. This matches Zach's analysis. We've filed bug 17285 for this problem. Is there any possibility to avoid splitting in case of multiple loads going together? Dm...

...matrix-matrix inner-kernel, I see a ~25% decrease in performance, >> which >> seems to be due to this. >> >> Any ideas why this changed? Thanks! >> >> >> This was intentional; apparently doing it with two instructions is >> supposed to be faster. See r172868/r172894. >> >> Adding Nadav in case he has anything more to say. >> >> -Eli >> >> >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130710/86bbc835/attachment.h...

...as a > single instruction (details below). > In a matrix-matrix inner-kernel, I see a ~25% decrease in performance, which > seems to be due to this. > > Any ideas why this changed? Thanks! This was intentional; apparently doing it with two instructions is supposed to be faster. See r172868/r172894. Adding Nadav in case he has anything more to say. -Eli

...tails below). >> In a matrix-matrix inner-kernel, I see a ~25% decrease in performance, which >> seems to be due to this. >> >> Any ideas why this changed? Thanks! > > This was intentional; apparently doing it with two instructions is > supposed to be faster. See r172868/r172894. > > Adding Nadav in case he has anything more to say. > > -Eli -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130709/c745e7fb/attachment.html>

...tion (details below). > In a matrix-matrix inner-kernel, I see a ~25% decrease in performance, > which > seems to be due to this. > > Any ideas why this changed? Thanks! > > > This was intentional; apparently doing it with two instructions is > supposed to be faster. See r172868/r172894. > > Adding Nadav in case he has anything more to say. > > -Eli > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130709/a7243480/attachment.html>

I'm seeing a difference in how LLVM 3.3 and 3.2 emit unaligned vector loads on AVX. 3.3 is splitting up an unaligned vector load but in 3.2, it was emitted as a single instruction (details below). In a matrix-matrix inner-kernel, I see a ~25% decrease in performance, which seems to be due to this. Any ideas why this changed? Thanks! Zach LLVM Code: define <4 x double> @vstore(<4 x