[llvm] r250724 - [Hexagon] Remove unnecessary argument sign extends
Krzysztof Parzyszek via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 19 12:10:49 PDT 2015
Author: kparzysz
Date: Mon Oct 19 14:10:48 2015
New Revision: 250724
URL: http://llvm.org/viewvc/llvm-project?rev=250724&view=rev
Log:
[Hexagon] Remove unnecessary argument sign extends
Added:
llvm/trunk/lib/Target/Hexagon/HexagonOptimizeSZextends.cpp
Modified:
llvm/trunk/lib/Target/Hexagon/CMakeLists.txt
llvm/trunk/lib/Target/Hexagon/HexagonTargetMachine.cpp
Modified: llvm/trunk/lib/Target/Hexagon/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/CMakeLists.txt?rev=250724&r1=250723&r2=250724&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/CMakeLists.txt (original)
+++ llvm/trunk/lib/Target/Hexagon/CMakeLists.txt Mon Oct 19 14:10:48 2015
@@ -35,6 +35,7 @@ add_llvm_target(HexagonCodeGen
HexagonMachineScheduler.cpp
HexagonMCInstLower.cpp
HexagonNewValueJump.cpp
+ HexagonOptimizeSZextends.cpp
HexagonPeephole.cpp
HexagonRegisterInfo.cpp
HexagonSelectionDAGInfo.cpp
Added: llvm/trunk/lib/Target/Hexagon/HexagonOptimizeSZextends.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonOptimizeSZextends.cpp?rev=250724&view=auto
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonOptimizeSZextends.cpp (added)
+++ llvm/trunk/lib/Target/Hexagon/HexagonOptimizeSZextends.cpp Mon Oct 19 14:10:48 2015
@@ -0,0 +1,150 @@
+//===- HexagonOptimizeSZextends.cpp - Remove unnecessary argument extends -===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Pass that removes sign extends for function parameters. These parameters
+// are already sign extended by the caller per Hexagon's ABI
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/MachineFunctionAnalysis.h"
+#include "llvm/CodeGen/StackProtector.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Scalar.h"
+
+#include "Hexagon.h"
+
+using namespace llvm;
+
+namespace llvm {
+ FunctionPass *createHexagonOptimizeSZextends();
+ void initializeHexagonOptimizeSZextendsPass(PassRegistry&);
+}
+
+namespace {
+ struct HexagonOptimizeSZextends : public FunctionPass {
+ public:
+ static char ID;
+ HexagonOptimizeSZextends() : FunctionPass(ID) {
+ initializeHexagonOptimizeSZextendsPass(*PassRegistry::getPassRegistry());
+ }
+ bool runOnFunction(Function &F) override;
+
+ const char *getPassName() const override {
+ return "Remove sign extends";
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<MachineFunctionAnalysis>();
+ AU.addPreserved<MachineFunctionAnalysis>();
+ AU.addPreserved<StackProtector>();
+ FunctionPass::getAnalysisUsage(AU);
+ }
+
+ bool intrinsicAlreadySextended(Intrinsic::ID IntID);
+ };
+}
+
+char HexagonOptimizeSZextends::ID = 0;
+
+INITIALIZE_PASS(HexagonOptimizeSZextends, "reargs",
+ "Remove Sign and Zero Extends for Args", false, false)
+
+bool HexagonOptimizeSZextends::intrinsicAlreadySextended(Intrinsic::ID IntID) {
+ switch(IntID) {
+ case llvm::Intrinsic::hexagon_A2_addh_l16_sat_ll:
+ return true;
+ default:
+ break;
+ }
+ return false;
+}
+
+bool HexagonOptimizeSZextends::runOnFunction(Function &F) {
+ unsigned Idx = 1;
+ // Try to optimize sign extends in formal parameters. It's relying on
+ // callee already sign extending the values. I'm not sure if our ABI
+ // requires callee to sign extend though.
+ for (auto &Arg : F.args()) {
+ if (F.getAttributes().hasAttribute(Idx, Attribute::SExt)) {
+ if (!isa<PointerType>(Arg.getType())) {
+ for (auto UI = Arg.use_begin(); UI != Arg.use_end();) {
+ if (isa<SExtInst>(*UI)) {
+ Instruction* Use = cast<Instruction>(*UI);
+ SExtInst* SI = new SExtInst(&Arg, Use->getType());
+ assert (EVT::getEVT(SI->getType()) ==
+ (EVT::getEVT(Use->getType())));
+ ++UI;
+ Use->replaceAllUsesWith(SI);
+ Instruction* First = F.getEntryBlock().begin();
+ SI->insertBefore(First);
+ Use->eraseFromParent();
+ } else {
+ ++UI;
+ }
+ }
+ }
+ }
+ ++Idx;
+ }
+
+ // Try to remove redundant sext operations on Hexagon. The hardware
+ // already sign extends many 16 bit intrinsic operations to 32 bits.
+ // For example:
+ // %34 = tail call i32 @llvm.hexagon.A2.addh.l16.sat.ll(i32 %x, i32 %y)
+ // %sext233 = shl i32 %34, 16
+ // %conv52 = ashr exact i32 %sext233, 16
+ for (auto &B : F) {
+ for (auto &I : B) {
+ // Look for arithmetic shift right by 16.
+ BinaryOperator *Ashr = dyn_cast<BinaryOperator>(&I);
+ if (!(Ashr && Ashr->getOpcode() == Instruction::AShr))
+ continue;
+ Value *AshrOp1 = Ashr->getOperand(1);
+ ConstantInt *C = dyn_cast<ConstantInt>(AshrOp1);
+ // Right shifted by 16.
+ if (!(C && C->getSExtValue() == 16))
+ continue;
+
+ // The first operand of Ashr comes from logical shift left.
+ Instruction *Shl = dyn_cast<Instruction>(Ashr->getOperand(0));
+ if (!(Shl && Shl->getOpcode() == Instruction::Shl))
+ continue;
+ Value *Intr = Shl->getOperand(0);
+ Value *ShlOp1 = Shl->getOperand(1);
+ C = dyn_cast<ConstantInt>(ShlOp1);
+ // Left shifted by 16.
+ if (!(C && C->getSExtValue() == 16))
+ continue;
+
+ // The first operand of Shl comes from an intrinsic.
+ if (IntrinsicInst *I = dyn_cast<IntrinsicInst>(Intr)) {
+ if (!intrinsicAlreadySextended(I->getIntrinsicID()))
+ continue;
+ // All is well. Replace all uses of AShr with I.
+ for (auto UI = Ashr->user_begin(), UE = Ashr->user_end();
+ UI != UE; ++UI) {
+ const Use &TheUse = UI.getUse();
+ if (Instruction *J = dyn_cast<Instruction>(TheUse.getUser())) {
+ J->replaceUsesOfWith(Ashr, I);
+ }
+ }
+ }
+ }
+ }
+
+ return true;
+}
+
+
+FunctionPass *llvm::createHexagonOptimizeSZextends() {
+ return new HexagonOptimizeSZextends();
+}
Modified: llvm/trunk/lib/Target/Hexagon/HexagonTargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonTargetMachine.cpp?rev=250724&r1=250723&r2=250724&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonTargetMachine.cpp (original)
+++ llvm/trunk/lib/Target/Hexagon/HexagonTargetMachine.cpp Mon Oct 19 14:10:48 2015
@@ -100,6 +100,7 @@ namespace llvm {
FunctionPass *createHexagonISelDag(HexagonTargetMachine &TM,
CodeGenOpt::Level OptLevel);
FunctionPass *createHexagonNewValueJump();
+ FunctionPass *createHexagonOptimizeSZextends();
FunctionPass *createHexagonPacketizer();
FunctionPass *createHexagonPeephole();
FunctionPass *createHexagonSplitConst32AndConst64();
@@ -213,6 +214,9 @@ bool HexagonPassConfig::addInstSelector(
HexagonTargetMachine &TM = getHexagonTargetMachine();
bool NoOpt = (getOptLevel() == CodeGenOpt::None);
+ if (!NoOpt)
+ addPass(createHexagonOptimizeSZextends());
+
addPass(createHexagonISelDag(TM, getOptLevel()));
if (!NoOpt) {
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