[all-commits] [llvm/llvm-project] 7c1054: [SelectionDAG] Fix usage of Align constructing Mac...

[Eli Friedman via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 7c10541e568f7453915d5d207c55f0fb7fb4c43c
      https://github.com/llvm/llvm-project/commit/7c10541e568f7453915d5d207c55f0fb7fb4c43c
  Author: Eli Friedman <efriedma at quicinc.com>
  Date:   2020-04-15 (Wed, 15 Apr 2020)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
    M llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
    M llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
    M llvm/lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp
    M llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
    M llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
    M llvm/test/CodeGen/PowerPC/aix-cc-abi.ll
    M llvm/test/CodeGen/RISCV/vararg.ll
    M llvm/test/CodeGen/X86/avx512-insert-extract.ll
    M llvm/test/CodeGen/X86/nosse-vector.ll
    M llvm/test/CodeGen/X86/sadd_sat_vec.ll
    M llvm/test/CodeGen/X86/ssub_sat_vec.ll
    M llvm/test/CodeGen/X86/uadd_sat_vec.ll
    M llvm/test/CodeGen/X86/usub_sat_vec.ll
    M llvm/test/CodeGen/X86/widen_cast-2.ll
    M llvm/test/CodeGen/X86/widen_load-2.ll

  Log Message:
  -----------
  [SelectionDAG] Fix usage of Align constructing MachineMemOperands.

The "Align" passed into getMachineMemOperand etc. is the alignment of
the MachinePointerInfo, not the alignment of the memory operation.
(getAlign() on a MachineMemOperand automatically reduces the alignment
to account for this.)

We were passing on wrong (overconservative) alignment in a bunch of
places. Fix a bunch of these, mostly in legalization.  And while I'm
here, switch to the new Align APIs.

The test changes are all scheduling changes: the biggest effect of
preserving large alignments is that it improves alias analysis, so the
scheduler has more freedom.

(I was originally just trying to do a minor cleanup in
SelectionDAGBuilder, but I accidentally went deeper down the rabbit
hole.)

Differential Revision: https://reviews.llvm.org/D77687