[PATCH] D67437: [SystemZ] Improve foldMemoryOperandImpl().

[Jonas Paulsson via Phabricator via llvm-commits]

jonpa updated this revision to Diff 237504.
jonpa marked 12 inline comments as done.
jonpa added a comment.

Patch updated per review (NFC). The new unused opcodes are gone, and the only superfluous mappings now added are in getMemOpcode():

  LOCFHR -> LOCFH
  LOCR   -> LOC

(which are not really "wrong")

Using reverseCCMask() includes the overflow bit being handled as well (and not checked for), but I suppose this must be equivalent since the compares never set the OF bit, right? (in combineCCMask and prepareCompareSwapOperands). It seems that we are with this patch using reverseCCMask() only for CCUsers in the presence of a compare. So to me it would make more sense to have an assert in reverseCCMask against the OF bit set, rather than handling it. This would be more overall readable given that we do introduce the use of the OF bit in SystemZElimCompare later on (or maybe I am missing something?). In other words, make it explit that the CCMask is produced by a compare and nothing else, like getSwappedCCMask() did. Would we want to use the OF (unordered bit) with FP compares?

Changed mnemonics per suggestion to MUX... This simplifies one line where just an "r" can be added, but the nested subst() in MemFoldPseudo_CondMove is not remedied. Can we still call this string 'mnemonic', or should it 'mnem' or something to show that it is not the same as the name of the instruction (on the other hand, it is already a pseudo opcode...)?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D67437/new/

https://reviews.llvm.org/D67437

Files:
  llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
  llvm/lib/Target/SystemZ/SystemZInstrFormats.td
  llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
  llvm/lib/Target/SystemZ/SystemZInstrInfo.h
  llvm/lib/Target/SystemZ/SystemZInstrInfo.td
  llvm/test/CodeGen/SystemZ/cond-move-10.ll
  llvm/test/CodeGen/SystemZ/int-cmp-56.mir

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