[PATCH] D21560: Relax the clearance calculating for breaking partial register dependency.

[Dehao Chen via llvm-commits]

danielcdh added a comment.

I just tested the perf impact of this patch for SPECCPU INT2006 benchmarks:

400.perlbench	2.21%
401.bzip2	-0.46%
403.gcc	1.59%
429.mcf	1.79%
445.gobmk	1.52%
456.hmmer	1.63%
458.sjeng	5.62%
462.libquantum	1.54%
464.h264ref	-1.28%
471.omnetpp	0.00%
473.astar	2.35%
483.xalancbmk	-0.27%
overall	1.29%

About the -Oz issue, I agree that there should be no xor inserted at -Oz. But that's a different issue and should be fixed in a separate patch.


http://reviews.llvm.org/D21560