Index: lib/Target/SystemZ/SystemZTargetTransformInfo.cpp =================================================================== --- lib/Target/SystemZ/SystemZTargetTransformInfo.cpp +++ lib/Target/SystemZ/SystemZTargetTransformInfo.cpp @@ -835,8 +835,17 @@ switch (Opcode) { case Instruction::ICmp: { unsigned Cost = 1; - if (ValTy->isIntegerTy() && ValTy->getScalarSizeInBits() <= 16) + if (ValTy->isIntegerTy() && ValTy->getScalarSizeInBits() <= 16) { + if (I != nullptr) { + // Single instruction for comparison of memory with a small immediate. + if (const LoadInst* Ld = dyn_cast(I->getOperand(0))) { + const Instruction *FoldedValue = nullptr; + if (isFoldableLoad(Ld, FoldedValue)) + return Cost; + } + } Cost += 2; // extend both operands + } return Cost; } case Instruction::Select: @@ -932,6 +941,12 @@ if (SExtBits || ZExtBits) return false; + // Comparison between memory and immediate. + if (UserI->getOpcode() == Instruction::ICmp) + if (ConstantInt *CI = dyn_cast(UserI->getOperand(1))) + if (isUInt<16>(CI->getZExtValue())) + return true; + unsigned LoadOrTruncBits = (TruncBits ? TruncBits : LoadedBits); return (LoadOrTruncBits == 32 || LoadOrTruncBits == 64); break; Index: test/Analysis/CostModel/SystemZ/cmp-mem.ll =================================================================== --- /dev/null +++ test/Analysis/CostModel/SystemZ/cmp-mem.ll @@ -0,0 +1,27 @@ +; RUN: opt < %s -cost-model -analyze -mtriple=systemz-unknown -mcpu=z13 | FileCheck %s +; +; Test costs for i8 and i16 comparisons against memory with a small immediate. + +define i32 @fun0(i8* %Src, i8* %Dst, i8 %Val) { +; CHECK: Printing analysis 'Cost Model Analysis' for function 'fun0': +; CHECK: Cost Model: Found an estimated cost of 0 for instruction: %Ld = load i8, i8* %Src +; CHECK: Cost Model: Found an estimated cost of 1 for instruction: %Cmp = icmp eq i8 %Ld, 123 +; CHECK: Cost Model: Found an estimated cost of 2 for instruction: %Ret = zext i1 %Cmp to i32 +; CHECK: Cost Model: Found an estimated cost of 0 for instruction: ret i32 %Ret + %Ld = load i8, i8* %Src + %Cmp = icmp eq i8 %Ld, 123 + %Ret = zext i1 %Cmp to i32 + ret i32 %Ret +} + +define i32 @fun1(i16* %Src, i16* %Dst, i16 %Val) { +; CHECK: Printing analysis 'Cost Model Analysis' for function 'fun1': +; CHECK: Cost Model: Found an estimated cost of 0 for instruction: %Ld = load i16, i16* %Src +; CHECK: Cost Model: Found an estimated cost of 1 for instruction: %Cmp = icmp eq i16 +; CHECK: Cost Model: Found an estimated cost of 2 for instruction: %Ret = zext i1 %Cmp to i32 +; CHECK: Cost Model: Found an estimated cost of 0 for instruction: ret i32 %Ret + %Ld = load i16, i16* %Src + %Cmp = icmp eq i16 %Ld, 1234 + %Ret = zext i1 %Cmp to i32 + ret i32 %Ret +}