From 4dfd590eaaa38aaa2ce7e09058d52780e445ae96 Mon Sep 17 00:00:00 2001 From: Juergen Ributzka Date: Tue, 14 Oct 2014 21:41:23 +0000 Subject: [PATCH] [FastISel][AArch64] Add custom lowering for GEPs. This is mostly a copy of the existing FastISel GEP code, but on AArch64 we bail out even for simple cases, because the standard fastEmit functions don't cover MUL and ADD is lowered inefficientily. llvm-svn: 219726 --- llvm/lib/Target/AArch64/AArch64FastISel.cpp | 85 +++++++++++++++++++ .../CodeGen/AArch64/arm64-fast-isel-alloca.ll | 5 +- llvm/test/CodeGen/AArch64/fast-isel-gep.ll | 18 ++++ 3 files changed, 105 insertions(+), 3 deletions(-) create mode 100644 llvm/test/CodeGen/AArch64/fast-isel-gep.ll diff --git a/llvm/lib/Target/AArch64/AArch64FastISel.cpp b/llvm/lib/Target/AArch64/AArch64FastISel.cpp index faf8ded45413..b074be9419cc 100644 --- a/llvm/lib/Target/AArch64/AArch64FastISel.cpp +++ b/llvm/lib/Target/AArch64/AArch64FastISel.cpp @@ -134,6 +134,7 @@ private: bool selectBitCast(const Instruction *I); bool selectFRem(const Instruction *I); bool selectSDiv(const Instruction *I); + bool selectGetElementPtr(const Instruction *I); // Utility helper routines. bool isTypeLegal(Type *Ty, MVT &VT); @@ -4541,6 +4542,88 @@ bool AArch64FastISel::selectSDiv(const Instruction *I) { return true; } +bool AArch64FastISel::selectGetElementPtr(const Instruction *I) { + unsigned N = getRegForValue(I->getOperand(0)); + if (!N) + return false; + bool NIsKill = hasTrivialKill(I->getOperand(0)); + + // Keep a running tab of the total offset to coalesce multiple N = N + Offset + // into a single N = N + TotalOffset. + uint64_t TotalOffs = 0; + Type *Ty = I->getOperand(0)->getType(); + MVT VT = TLI.getPointerTy(); + for (auto OI = std::next(I->op_begin()), E = I->op_end(); OI != E; ++OI) { + const Value *Idx = *OI; + if (auto *StTy = dyn_cast(Ty)) { + unsigned Field = cast(Idx)->getZExtValue(); + // N = N + Offset + if (Field) + TotalOffs += DL.getStructLayout(StTy)->getElementOffset(Field); + Ty = StTy->getElementType(Field); + } else { + Ty = cast(Ty)->getElementType(); + // If this is a constant subscript, handle it quickly. + if (const auto *CI = dyn_cast(Idx)) { + if (CI->isZero()) + continue; + // N = N + Offset + TotalOffs += + DL.getTypeAllocSize(Ty) * cast(CI)->getSExtValue(); + continue; + } + if (TotalOffs) { + N = emitAddSub_ri(/*UseAdd=*/true, VT, N, NIsKill, TotalOffs); + if (!N) { + unsigned C = fastEmit_i(VT, VT, ISD::Constant, TotalOffs); + if (!C) + return false; + N = emitAddSub_rr(/*UseAdd=*/true, VT, N, NIsKill, C, true); + if (!N) + return false; + } + NIsKill = true; + TotalOffs = 0; + } + + // N = N + Idx * ElementSize; + uint64_t ElementSize = DL.getTypeAllocSize(Ty); + std::pair Pair = getRegForGEPIndex(Idx); + unsigned IdxN = Pair.first; + bool IdxNIsKill = Pair.second; + if (!IdxN) + return false; + + if (ElementSize != 1) { + unsigned C = fastEmit_i(VT, VT, ISD::Constant, ElementSize); + if (!C) + return false; + IdxN = emitMul_rr(VT, IdxN, IdxNIsKill, C, true); + if (!IdxN) + return false; + IdxNIsKill = true; + } + N = fastEmit_rr(VT, VT, ISD::ADD, N, NIsKill, IdxN, IdxNIsKill); + if (!N) + return false; + } + } + if (TotalOffs) { + N = emitAddSub_ri(/*UseAdd=*/true, VT, N, NIsKill, TotalOffs); + if (!N) { + unsigned C = fastEmit_i(VT, VT, ISD::Constant, TotalOffs); + if (!C) + return false; + N = emitAddSub_rr(/*UseAdd=*/true, VT, N, NIsKill, C, true); + if (!N) + return false; + } + } + + updateValueMap(I, N); + return true; +} + bool AArch64FastISel::fastSelectInstruction(const Instruction *I) { switch (I->getOpcode()) { default: @@ -4612,6 +4695,8 @@ bool AArch64FastISel::fastSelectInstruction(const Instruction *I) { return selectRet(I); case Instruction::FRem: return selectFRem(I); + case Instruction::GetElementPtr: + return selectGetElementPtr(I); } // fall-back to target-independent instruction selection. diff --git a/llvm/test/CodeGen/AArch64/arm64-fast-isel-alloca.ll b/llvm/test/CodeGen/AArch64/arm64-fast-isel-alloca.ll index 34394b2af0a7..a8417027ce2d 100644 --- a/llvm/test/CodeGen/AArch64/arm64-fast-isel-alloca.ll +++ b/llvm/test/CodeGen/AArch64/arm64-fast-isel-alloca.ll @@ -15,9 +15,8 @@ define void @main() nounwind { entry: ; CHECK: main ; CHECK: mov x29, sp -; CHECK: mov x[[REG:[0-9]+]], sp -; CHECK-NEXT: orr x[[REG1:[0-9]+]], xzr, #0x8 -; CHECK-NEXT: add x0, x[[REG]], x[[REG1]] +; CHECK: mov [[REG:x[0-9]+]], sp +; CHECK-NEXT: add x0, [[REG]], #8 %E = alloca %struct.S2Ty, align 4 %B = getelementptr inbounds %struct.S2Ty* %E, i32 0, i32 1 call void @takeS1(%struct.S1Ty* %B) diff --git a/llvm/test/CodeGen/AArch64/fast-isel-gep.ll b/llvm/test/CodeGen/AArch64/fast-isel-gep.ll new file mode 100644 index 000000000000..d72019801bae --- /dev/null +++ b/llvm/test/CodeGen/AArch64/fast-isel-gep.ll @@ -0,0 +1,18 @@ +; RUN: llc -mtriple=aarch64-apple-darwin -fast-isel -fast-isel-abort -verify-machineinstrs < %s | FileCheck %s + +%struct.foo = type { i32, i64, float, double } + +define double* @test_struct(%struct.foo* %f) { +; CHECK-LABEL: test_struct +; CHECK: add x0, x0, #24 + %1 = getelementptr inbounds %struct.foo* %f, i64 0, i32 3 + ret double* %1 +} + +define i32* @test_array(i32* %a, i64 %i) { +; CHECK-LABEL: test_array +; CHECK: orr [[REG:x[0-9]+]], xzr, #0x4 +; CHECK-NEXT: madd x0, x1, [[REG]], x0 + %1 = getelementptr inbounds i32* %a, i64 %i + ret i32* %1 +}