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712cf3fb41
Summary:
while investigating performance degradation of imagick benchmark
there were found inefficient pattern for UINT_TO_FP conversion.
That pattern causes RAW hazard in assembly code. Specifically,
uitofp IR operator results in poor assembler :
st %i0, [%fp - 952]
ldd [%fp - 952], %f0
it stores 32-bit integer register into memory location and then
loads 64-bit floating point data from that location.
That is exactly RAW hazard case. To optimize that case it is
possible to use SPISD::ITOF and SPISD::XTOF for conversion from
integer to floating point data type and to use ISD::BITCAST to
copy from integer register into floating point register.
The fix is to write custom UINT_TO_FP pattern using SPISD::ITOF,
SPISD::XTOF, ISD::BITCAST.
Patch by Alexey Lapshin
Reviewers: fedor.sergeev, jyknight, dcederman, lero_chris
Reviewed By: jyknight
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D36875
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318704 91177308-0d34-0410-b5e6-96231b3b80d8