[PATCH] D122482: [X86] combineADC - fold ADC(C1,C2,Carry) -> ADC(0,C1+C2,Carry)

[Simon Pilgrim via Phabricator via llvm-commits]

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If we're not relying on the flag result, we can fold the constants together into the RHS immediate operand and set the LHS operand to zero, simplifying for further folds.

We could do something similar if the flag result is in use and the constant fold doesn't affect it, but I don't have any real test cases for this yet.

As suggested by @davezarzycki on Issue #35256


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D122482

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/call-rv-marker.ll
  llvm/test/CodeGen/X86/combine-adc.ll
  llvm/test/CodeGen/X86/combine-add.ll
  llvm/test/CodeGen/X86/pr16031.ll
  llvm/test/CodeGen/X86/scheduler-backtracking.ll
  llvm/test/CodeGen/X86/setcc.ll

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