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author | Hal Finkel <hfinkel@anl.gov> | 2013-05-16 19:58:38 +0000 |
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committer | Hal Finkel <hfinkel@anl.gov> | 2013-05-16 19:58:38 +0000 |
commit | c482454e3cc2a33a2cf2d1cf0881c7c5e2641c80 (patch) | |
tree | 6880887689abe3c97fd79a896ab470b8da4090b7 /lib/Target | |
parent | 02e168003f45cf8e0a277c6b8c85c1a3032b1dec (diff) | |
download | llvm-c482454e3cc2a33a2cf2d1cf0881c7c5e2641c80.tar.gz llvm-c482454e3cc2a33a2cf2d1cf0881c7c5e2641c80.tar.bz2 llvm-c482454e3cc2a33a2cf2d1cf0881c7c5e2641c80.tar.xz |
Create an new preheader in PPCCTRLoops to avoid counter register clobbers
Some IR-level instructions (such as FP <-> i64 conversions) are not chained
w.r.t. the mtctr intrinsic and yet may become function calls that clobber the
counter register. At the selection-DAG level, these might be reordered with the
mtctr intrinsic causing miscompiles. To avoid this situation, if an existing
preheader has instructions that might use the counter register, create a new
preheader for the mtctr intrinsic. This extra block will be remerged with the
old preheader at the MI level, but will prevent unwanted reordering at the
selection-DAG level.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182045 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target')
-rw-r--r-- | lib/Target/PowerPC/PPCCTRLoops.cpp | 318 |
1 files changed, 165 insertions, 153 deletions
diff --git a/lib/Target/PowerPC/PPCCTRLoops.cpp b/lib/Target/PowerPC/PPCCTRLoops.cpp index 6bbd571894..5d001fc072 100644 --- a/lib/Target/PowerPC/PPCCTRLoops.cpp +++ b/lib/Target/PowerPC/PPCCTRLoops.cpp @@ -96,6 +96,7 @@ namespace { SmallVectorImpl<BasicBlock*> &SplitPreds, Loop *L); + bool mightUseCTR(const Triple &TT, BasicBlock *BB); bool convertToCTRLoop(Loop *L); private: PPCTargetMachine *TM; @@ -143,6 +144,161 @@ bool PPCCTRLoops::runOnFunction(Function &F) { return MadeChange; } +bool PPCCTRLoops::mightUseCTR(const Triple &TT, BasicBlock *BB) { + for (BasicBlock::iterator J = BB->begin(), JE = BB->end(); + J != JE; ++J) { + if (CallInst *CI = dyn_cast<CallInst>(J)) { + if (!TM) + return true; + const TargetLowering *TLI = TM->getTargetLowering(); + + if (Function *F = CI->getCalledFunction()) { + // Most intrinsics don't become function calls, but some might. + // sin, cos, exp and log are always calls. + unsigned Opcode; + if (F->getIntrinsicID() != Intrinsic::not_intrinsic) { + switch (F->getIntrinsicID()) { + default: continue; + +// VisualStudio defines setjmp as _setjmp +#if defined(_MSC_VER) && defined(setjmp) && \ + !defined(setjmp_undefined_for_msvc) +# pragma push_macro("setjmp") +# undef setjmp +# define setjmp_undefined_for_msvc +#endif + + case Intrinsic::setjmp: + +#if defined(_MSC_VER) && defined(setjmp_undefined_for_msvc) + // let's return it to _setjmp state +# pragma pop_macro("setjmp") +# undef setjmp_undefined_for_msvc +#endif + + case Intrinsic::longjmp: + case Intrinsic::memcpy: + case Intrinsic::memmove: + case Intrinsic::memset: + case Intrinsic::powi: + case Intrinsic::log: + case Intrinsic::log2: + case Intrinsic::log10: + case Intrinsic::exp: + case Intrinsic::exp2: + case Intrinsic::pow: + case Intrinsic::sin: + case Intrinsic::cos: + return true; + case Intrinsic::sqrt: Opcode = ISD::FSQRT; break; + case Intrinsic::floor: Opcode = ISD::FFLOOR; break; + case Intrinsic::ceil: Opcode = ISD::FCEIL; break; + case Intrinsic::trunc: Opcode = ISD::FTRUNC; break; + case Intrinsic::rint: Opcode = ISD::FRINT; break; + case Intrinsic::nearbyint: Opcode = ISD::FNEARBYINT; break; + } + } + + // PowerPC does not use [US]DIVREM or other library calls for + // operations on regular types which are not otherwise library calls + // (i.e. soft float or atomics). If adapting for targets that do, + // additional care is required here. + + LibFunc::Func Func; + if (!F->hasLocalLinkage() && F->hasName() && LibInfo && + LibInfo->getLibFunc(F->getName(), Func) && + LibInfo->hasOptimizedCodeGen(Func)) { + // Non-read-only functions are never treated as intrinsics. + if (!CI->onlyReadsMemory()) + return true; + + // Conversion happens only for FP calls. + if (!CI->getArgOperand(0)->getType()->isFloatingPointTy()) + return true; + + switch (Func) { + default: return true; + case LibFunc::copysign: + case LibFunc::copysignf: + case LibFunc::copysignl: + continue; // ISD::FCOPYSIGN is never a library call. + case LibFunc::fabs: + case LibFunc::fabsf: + case LibFunc::fabsl: + continue; // ISD::FABS is never a library call. + case LibFunc::sqrt: + case LibFunc::sqrtf: + case LibFunc::sqrtl: + Opcode = ISD::FSQRT; break; + case LibFunc::floor: + case LibFunc::floorf: + case LibFunc::floorl: + Opcode = ISD::FFLOOR; break; + case LibFunc::nearbyint: + case LibFunc::nearbyintf: + case LibFunc::nearbyintl: + Opcode = ISD::FNEARBYINT; break; + case LibFunc::ceil: + case LibFunc::ceilf: + case LibFunc::ceill: + Opcode = ISD::FCEIL; break; + case LibFunc::rint: + case LibFunc::rintf: + case LibFunc::rintl: + Opcode = ISD::FRINT; break; + case LibFunc::trunc: + case LibFunc::truncf: + case LibFunc::truncl: + Opcode = ISD::FTRUNC; break; + } + + MVT VTy = + TLI->getSimpleValueType(CI->getArgOperand(0)->getType(), true); + if (VTy == MVT::Other) + return true; + + if (TLI->isOperationLegalOrCustom(Opcode, VTy)) + continue; + else if (VTy.isVector() && + TLI->isOperationLegalOrCustom(Opcode, VTy.getScalarType())) + continue; + + return true; + } + } + + return true; + } else if (isa<BinaryOperator>(J) && + J->getType()->getScalarType()->isPPC_FP128Ty()) { + // Most operations on ppc_f128 values become calls. + return true; + } else if (isa<UIToFPInst>(J) || isa<SIToFPInst>(J) || + isa<FPToUIInst>(J) || isa<FPToSIInst>(J)) { + CastInst *CI = cast<CastInst>(J); + if (CI->getSrcTy()->getScalarType()->isPPC_FP128Ty() || + CI->getDestTy()->getScalarType()->isPPC_FP128Ty() || + (TT.isArch32Bit() && + (CI->getSrcTy()->getScalarType()->isIntegerTy(64) || + CI->getDestTy()->getScalarType()->isIntegerTy(64)) + )) + return true; + } else if (isa<IndirectBrInst>(J) || isa<InvokeInst>(J)) { + // On PowerPC, indirect jumps use the counter register. + return true; + } else if (SwitchInst *SI = dyn_cast<SwitchInst>(J)) { + if (!TM) + return true; + const TargetLowering *TLI = TM->getTargetLowering(); + + if (TLI->supportJumpTables() && + SI->getNumCases()+1 >= (unsigned) TLI->getMinimumJumpTableEntries()) + return true; + } + } + + return false; +} + bool PPCCTRLoops::convertToCTRLoop(Loop *L) { bool MadeChange = false; @@ -173,158 +329,9 @@ bool PPCCTRLoops::convertToCTRLoop(Loop *L) { // We don't want to spill/restore the counter register, and so we don't // want to use the counter register if the loop contains calls. for (Loop::block_iterator I = L->block_begin(), IE = L->block_end(); - I != IE; ++I) { - for (BasicBlock::iterator J = (*I)->begin(), JE = (*I)->end(); - J != JE; ++J) { - if (CallInst *CI = dyn_cast<CallInst>(J)) { - if (!TM) - return MadeChange; - const TargetLowering *TLI = TM->getTargetLowering(); - - if (Function *F = CI->getCalledFunction()) { - // Most intrinsics don't become function calls, but some might. - // sin, cos, exp and log are always calls. - unsigned Opcode; - if (F->getIntrinsicID() != Intrinsic::not_intrinsic) { - switch (F->getIntrinsicID()) { - default: continue; - -// VisualStudio defines setjmp as _setjmp -#if defined(_MSC_VER) && defined(setjmp) && \ - !defined(setjmp_undefined_for_msvc) -# pragma push_macro("setjmp") -# undef setjmp -# define setjmp_undefined_for_msvc -#endif - - case Intrinsic::setjmp: - -#if defined(_MSC_VER) && defined(setjmp_undefined_for_msvc) - // let's return it to _setjmp state -# pragma pop_macro("setjmp") -# undef setjmp_undefined_for_msvc -#endif - - case Intrinsic::longjmp: - case Intrinsic::memcpy: - case Intrinsic::memmove: - case Intrinsic::memset: - case Intrinsic::powi: - case Intrinsic::log: - case Intrinsic::log2: - case Intrinsic::log10: - case Intrinsic::exp: - case Intrinsic::exp2: - case Intrinsic::pow: - case Intrinsic::sin: - case Intrinsic::cos: - return MadeChange; - case Intrinsic::sqrt: Opcode = ISD::FSQRT; break; - case Intrinsic::floor: Opcode = ISD::FFLOOR; break; - case Intrinsic::ceil: Opcode = ISD::FCEIL; break; - case Intrinsic::trunc: Opcode = ISD::FTRUNC; break; - case Intrinsic::rint: Opcode = ISD::FRINT; break; - case Intrinsic::nearbyint: Opcode = ISD::FNEARBYINT; break; - } - } - - // PowerPC does not use [US]DIVREM or other library calls for - // operations on regular types which are not otherwise library calls - // (i.e. soft float or atomics). If adapting for targets that do, - // additional care is required here. - - LibFunc::Func Func; - if (!F->hasLocalLinkage() && F->hasName() && LibInfo && - LibInfo->getLibFunc(F->getName(), Func) && - LibInfo->hasOptimizedCodeGen(Func)) { - // Non-read-only functions are never treated as intrinsics. - if (!CI->onlyReadsMemory()) - return MadeChange; - - // Conversion happens only for FP calls. - if (!CI->getArgOperand(0)->getType()->isFloatingPointTy()) - return MadeChange; - - switch (Func) { - default: return MadeChange; - case LibFunc::copysign: - case LibFunc::copysignf: - case LibFunc::copysignl: - continue; // ISD::FCOPYSIGN is never a library call. - case LibFunc::fabs: - case LibFunc::fabsf: - case LibFunc::fabsl: - continue; // ISD::FABS is never a library call. - case LibFunc::sqrt: - case LibFunc::sqrtf: - case LibFunc::sqrtl: - Opcode = ISD::FSQRT; break; - case LibFunc::floor: - case LibFunc::floorf: - case LibFunc::floorl: - Opcode = ISD::FFLOOR; break; - case LibFunc::nearbyint: - case LibFunc::nearbyintf: - case LibFunc::nearbyintl: - Opcode = ISD::FNEARBYINT; break; - case LibFunc::ceil: - case LibFunc::ceilf: - case LibFunc::ceill: - Opcode = ISD::FCEIL; break; - case LibFunc::rint: - case LibFunc::rintf: - case LibFunc::rintl: - Opcode = ISD::FRINT; break; - case LibFunc::trunc: - case LibFunc::truncf: - case LibFunc::truncl: - Opcode = ISD::FTRUNC; break; - } - - MVT VTy = - TLI->getSimpleValueType(CI->getArgOperand(0)->getType(), true); - if (VTy == MVT::Other) - return MadeChange; - - if (TLI->isOperationLegalOrCustom(Opcode, VTy)) - continue; - else if (VTy.isVector() && - TLI->isOperationLegalOrCustom(Opcode, VTy.getScalarType())) - continue; - - return MadeChange; - } - } - - return MadeChange; - } else if (isa<BinaryOperator>(J) && - J->getType()->getScalarType()->isPPC_FP128Ty()) { - // Most operations on ppc_f128 values become calls. - return MadeChange; - } else if (isa<UIToFPInst>(J) || isa<SIToFPInst>(J) || - isa<FPToUIInst>(J) || isa<FPToSIInst>(J)) { - CastInst *CI = cast<CastInst>(J); - if (CI->getSrcTy()->getScalarType()->isPPC_FP128Ty() || - CI->getDestTy()->getScalarType()->isPPC_FP128Ty() || - (TT.isArch32Bit() && - (CI->getSrcTy()->getScalarType()->isIntegerTy(64) || - CI->getDestTy()->getScalarType()->isIntegerTy(64)) - )) - return MadeChange; - } else if (isa<IndirectBrInst>(J) || isa<InvokeInst>(J)) { - // On PowerPC, indirect jumps use the counter register. - return MadeChange; - } else if (SwitchInst *SI = dyn_cast<SwitchInst>(J)) { - if (!TM) - return MadeChange; - const TargetLowering *TLI = TM->getTargetLowering(); - - if (TLI->supportJumpTables() && - SI->getNumCases()+1 >= (unsigned) TLI->getMinimumJumpTableEntries()) - return MadeChange; - } - } - } + I != IE; ++I) + if (mightUseCTR(TT, *I)) + return MadeChange; SmallVector<BasicBlock*, 4> ExitingBlocks; L->getExitingBlocks(ExitingBlocks); @@ -391,7 +398,12 @@ bool PPCCTRLoops::convertToCTRLoop(Loop *L) { return MadeChange; BasicBlock *Preheader = L->getLoopPreheader(); - if (!Preheader) + + // If we don't have a preheader, then insert one. If we already have a + // preheader, then we can use it (except if the preheader contains a use of + // the CTR register because some such uses might be reordered by the + // selection DAG after the mtctr instruction). + if (!Preheader || mightUseCTR(TT, Preheader)) Preheader = InsertPreheaderForLoop(L); if (!Preheader) return MadeChange; |