[llvm-commits] [PATCH] Prevent the mixing of S and D registers for vsqrt/vdiv instructions on A15

Silviu Baranga silbar01 at arm.com
Fri Sep 14 06:16:47 PDT 2012


Hi,

The attached patch prevents the mixing of D and S registers for vsqrt/vdiv
instructions when using neonfp on A15. This is necessary since single
precision math instructions use D registers when using neonfp, and there
are no equivalent instructions for vsqrt and vdiv.

This is achieved by using a vdup instruction on the super D register of
the output S register. Our benchmarks show that this solution is only
profitable for A15.

Please review.

Thanks,
Silviu
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