[llvm-dev] llvm PeepholeOptimizer + optimizeLoadInstr question

[Andrew Zhogin via llvm-dev]

Hello Lang,

PeepholeOptimizer allows backend to provide optimizeLoadInstr function to
fold memory-load operand.

But it doesn't work for folding load operand into store instruction
(combine into memory-to-memory instruction).
It is rare case, but some backends have such instructions (like SystemZ
MVC).

It doesn't work because "FoldAsLoadDefCandidates.clear()" occurs too early,
before current instruction "optimizeLoadInstr" check.

Could "FoldAsLoadDefCandidates.clear()" be moved later?

After "!isLoadFoldable(...) && !FoldAsLoadDefCandidates.empty()" condition
check.

-- 
Thanks,
Andrew
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