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Author: AZero13

llvm/lib/Target/ARM/ARMInstrInfo.td

@@ -2202,6 +2202,9 @@ def JUMPTABLE_TBH :
 PseudoInst<(outs), (ins cpinst_operand:$instid, cpinst_operand:$cpidx,
                         i32imm:$size), NoItinerary, []>;
 
+// FIXME: Marking these as hasSideEffects is necessary to prevent machine DCE
+// from removing one half of the matched pairs. That breaks PEI, which assumes
+// these will always be in pairs, and asserts if it finds otherwise. Better way?
 let Defs = [SP], Uses = [SP], hasSideEffects = 1 in {
 def ADJCALLSTACKUP :
 PseudoInst<(outs), (ins i32imm:$amt1, i32imm:$amt2, pred:$p), NoItinerary,