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[SystemZ] Add a mapping from "select register" to "load on condition" (2-addr).

Authored by jonpa on Dec 17 2019, 10:17 AM.

Description

[SystemZ] Add a mapping from "select register" to "load on condition" (2-addr).

The SELR(Mux) instructions can be converted to two-address form as LOCR(Mux)
instructions whenever one of the sources are the same reg as dest. By adding
this mapping in getTwoOperandOpcode(), we get:

  • Two-address hints in getRegAllocationHints() for select register instructions.
  • No need anymore for special handling in SystemZShortenInst.cpp - shortenSelect() removed.

The two-address hints are now added before the GRX32 hints, which should be
preferred.

Review: Ulrich Weigand
https://reviews.llvm.org/D68870

Details

Committed
jonpaDec 20 2019, 10:44 AM
Parents
rGa805e0fb18ca: [lldb][NFC] Remove utility methods in TestClangASTImporter
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