[ARM][NFC] Avoid recreating MCSubtargetInfo in ARMAsmBackend

Description

[ARM][NFC] Avoid recreating MCSubtargetInfo in ARMAsmBackend

After D41349, we can now directly access MCSubtargetInfo from
createARM*AsmBackend. This patch makes use of this, avoiding the need to
create a fresh MCSubtargetInfo (which was previously always done with a blank
CPU and feature string). Given the total size of the change remains pretty
tiny and we're removing the old explicit destructor, I changed the STI field
to a reference rather than a pointer.

Differential Revision: https://reviews.llvm.org/D41693

Details

Committed
asbWed, Jan 3, 5:46 AM
Differential Revision
D41693: [ARM][NFC] Avoid recreating MCSubtargetInfo in ARMAsmBackend
Parents
rL321706: [InstCombine] Add test to remove VarArg casts (NFC)
Branches
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