diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp --- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp +++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp @@ -2812,6 +2812,16 @@ return LT.first * 4; // fcvtl + fcvtl + fcmp + xtn } + // Treat the icmp in icmp(and, 0) as free, as we can make use of ands. + // FIXME: This can apply to more conditions and add/sub if it can be shown to + // be profitable. + if (ValTy->isIntegerTy() && ISD == ISD::SETCC && I && + ICmpInst::isEquality(VecPred) && + TLI->isTypeLegal(TLI->getValueType(DL, ValTy)) && + match(I->getOperand(1), m_Zero()) && + match(I->getOperand(0), m_And(m_Value(), m_Value()))) + return 0; + // The base case handles scalable vectors fine for now, since it treats the // cost as 1 * legalization cost. return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind, I); diff --git a/llvm/test/Analysis/CostModel/AArch64/cmp.ll b/llvm/test/Analysis/CostModel/AArch64/cmp.ll --- a/llvm/test/Analysis/CostModel/AArch64/cmp.ll +++ b/llvm/test/Analysis/CostModel/AArch64/cmp.ll @@ -64,9 +64,9 @@ ; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %a16 = and i16 undef, undef ; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %c16 = icmp ne i16 %a16, 0 ; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %a32 = and i32 undef, undef -; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %c32 = icmp eq i32 %a32, 0 +; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %c32 = icmp eq i32 %a32, 0 ; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %a64 = and i64 undef, undef -; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %c64 = icmp ne i64 %a64, 0 +; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 0 for instruction: %c64 = icmp ne i64 %a64, 0 ; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 2 for instruction: %a128 = and i128 undef, undef ; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 2 for instruction: %c128 = icmp eq i128 %a128, 0 ; CHECK-THROUGHPUT-NEXT: Cost Model: Found an estimated cost of 1 for instruction: %av16i8 = and <16 x i8> undef, undef