Hsiangkai Wang 137d3474ca [RISCV] Reverse the order of loading/storing callee-saved registers. ...

Currently, we restore the return address register as the last restoring
instruction in the epilog. The next instruction is `ret` usually. It is
a use of return address register. In some microarchitectures, there is
load-to-use data hazard. To avoid the load-to-use data hazard, we could
separate the load instruction from its use as far as possible. In this
patch, we reverse the order of restoring callee-saved registers to
increase the distance of `load ra` and `ret` in the epilog.

Differential Revision: https://reviews.llvm.org/D113967

2021-11-22 23:02:11 +08:00

2.4 KiB

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