[AArch64][GlobalISel] Enable copy elision in the pre-legalizer combine and fix a crash.
This enables the simple copy combine that already exists in the CombinerHelper.
However, it exposed a bug in the GISelChangeObserver where it wouldn't clear a
set of MIs to process, and so would end up causing a crash when deleted MIs were
being added to the combiner worklist again.
Differential Revision: https://reviews.llvm.org/D60579
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358318
91177308-0d34-0410-b5e6-
96231b3b80d8
projects / llvm / commit