[PATCH] D130931: [RISCV] Teach RISCVMergeBaseOffset to merge %lo/%pcrel_lo into load/store after folding arithmetic.

[Craig Topper via Phabricator via llvm-commits]

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It's possible we have:
lui  a0, %hi(sym)
addi a0, %lo(sym)
addi a0, <offset1>
lw a0, <offset2>(a0)

We want to arrive at
lui a0, %hi(sym+offset1+offset2)
lw a0, %lo(sym+offset1+offset2)

We currently fail to do this because we only consider loads/stores
if we didn't find any arithmetic.

This patch splits arithmetic folding and load/store folding into
two separate phases. The load/store folding can no longer assume
the offset in hi/lo is 0 so we must combine the offsets. I've applied
the same simm32 limit that we applied in the arithmetic folding.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D130931

Files:
  llvm/lib/Target/RISCV/RISCVMergeBaseOffset.cpp
  llvm/test/CodeGen/RISCV/hoist-global-addr-base.ll

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