[PATCH] D110739: [CostModel] Update default cost model for sadd/ssub overflow to match TargetLowering

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/include/llvm/CodeGen/BasicTTIImpl.h:1797
       InstructionCost Cost = 0;
       Cost += thisT()->getArithmeticInstrCost(Opcode, SumTy, CostKind);
       Cost += 2 * thisT()->getCmpSelInstrCost(
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Worth trying to specify the Args as well via the IntrinsicCostAttributes arg?


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Comment at: llvm/include/llvm/CodeGen/BasicTTIImpl.h:1800
+                      Instruction::ICmp, SumTy, OverflowTy,
                       CmpInst::BAD_ICMP_PREDICATE, CostKind);
+      Cost += thisT()->getArithmeticInstrCost(BinaryOperator::Xor, OverflowTy,
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Can we specify the predicate (ICMP_SGT) as well? I've been meaning to deal with PR48337 for ages so X86 actually uses it...


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  https://reviews.llvm.org/D110739/new/

https://reviews.llvm.org/D110739