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| author | Sanjay Patel <spatel@rotateright.com> | 2014-10-24 17:02:16 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2014-10-24 17:02:16 +0000 |
| commit | 957efc23bb87d341a1b478d87a48bb888c2d4068 (patch) | |
| tree | 48ae584987b7970cb90899c03590938f4d622799 /llvm/lib/Bitcode | |
| parent | 5e3a421bfcb891fc7821daa501e30c113fb1bf16 (diff) | |
| download | bcm5719-llvm-957efc23bb87d341a1b478d87a48bb888c2d4068.tar.gz bcm5719-llvm-957efc23bb87d341a1b478d87a48bb888c2d4068.zip | |
Use rsqrt (X86) to speed up reciprocal square root calcs
This is a first step for generating SSE rsqrt instructions for
reciprocal square root calcs when fast-math is allowed.
For now, be conservative and only enable this for AMD btver2
where performance improves significantly - for example, 29%
on llvm/projects/test-suite/SingleSource/Benchmarks/BenchmarkGame/n-body.c
(if we convert the data type to single-precision float).
This patch adds a two constant version of the Newton-Raphson
refinement algorithm to DAGCombiner that can be selected by any target
via a parameter returned by getRsqrtEstimate()..
See PR20900 for more details:
http://llvm.org/bugs/show_bug.cgi?id=20900
Differential Revision: http://reviews.llvm.org/D5658
llvm-svn: 220570
Diffstat (limited to 'llvm/lib/Bitcode')
0 files changed, 0 insertions, 0 deletions
