Date: Wed, 8 Sep 2021 18:16:28 GMT From: "Alfredo Dal'Ava Junior" <alfredo@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: d8199cf063f0 - stable/13 - llvm: Revert "[HardwareLoops] Change order of SCEV expression construction for InitLoopCount." Message-ID: <202109081816.188IGSQu008869@gitrepo.freebsd.org>
next in thread | raw e-mail | index | archive | help
The branch stable/13 has been updated by alfredo: URL: https://cgit.FreeBSD.org/src/commit/?id=d8199cf063f055cd527767ff0bf2b01b3e598c9f commit d8199cf063f055cd527767ff0bf2b01b3e598c9f Author: Alfredo Dal'Ava Junior <alfredo@FreeBSD.org> AuthorDate: 2021-09-02 17:54:31 +0000 Commit: Alfredo Dal'Ava Junior <alfredo@FreeBSD.org> CommitDate: 2021-09-08 21:16:20 +0000 llvm: Revert "[HardwareLoops] Change order of SCEV expression construction for InitLoopCount." Reverts llvm commit 42eaf4fe0adef3344adfd9fbccd49f325cb549ef, pointed from bisect as source of regression that causes liblzma to compress/ uncompress incorrectly. It's know to affect powerpc64 BE only. The patch unbreaks FreeBSD powerpc64 installation media, since bsdinstall can't uncompress the *.txz produced by FreeBSD CI. It's probably miscompiling other software bas well. Upstream PR: https://bugs.llvm.org/show_bug.cgi?id=51714 Reviewed by: dim MFC after: 2 days Sponsored by: Instituto de Pesquisas Eldorado (eldorado.org.br) Differential Revision: https://reviews.freebsd.org/D31804 (cherry picked from commit f21fcae487026987f44154de981c03b69efbc945) --- .../include/llvm/Analysis/TargetTransformInfo.h | 1 + .../llvm/lib/Analysis/TargetTransformInfo.cpp | 5 +---- .../llvm/lib/CodeGen/HardwareLoops.cpp | 26 +++++++++++++--------- 3 files changed, 18 insertions(+), 14 deletions(-) diff --git a/contrib/llvm-project/llvm/include/llvm/Analysis/TargetTransformInfo.h b/contrib/llvm-project/llvm/include/llvm/Analysis/TargetTransformInfo.h index cdfb04424e56..4dc442e1ed56 100644 --- a/contrib/llvm-project/llvm/include/llvm/Analysis/TargetTransformInfo.h +++ b/contrib/llvm-project/llvm/include/llvm/Analysis/TargetTransformInfo.h @@ -94,6 +94,7 @@ struct HardwareLoopInfo { Loop *L = nullptr; BasicBlock *ExitBlock = nullptr; BranchInst *ExitBranch = nullptr; + const SCEV *ExitCount = nullptr; const SCEV *TripCount = nullptr; IntegerType *CountType = nullptr; Value *LoopDecrement = nullptr; // Decrement the loop counter by this diff --git a/contrib/llvm-project/llvm/lib/Analysis/TargetTransformInfo.cpp b/contrib/llvm-project/llvm/lib/Analysis/TargetTransformInfo.cpp index e498401eb8b5..43cc90aedbc9 100644 --- a/contrib/llvm-project/llvm/lib/Analysis/TargetTransformInfo.cpp +++ b/contrib/llvm-project/llvm/lib/Analysis/TargetTransformInfo.cpp @@ -217,10 +217,7 @@ bool HardwareLoopInfo::isHardwareLoopCandidate(ScalarEvolution &SE, // Note that this block may not be the loop latch block, even if the loop // has a latch block. ExitBlock = BB; - TripCount = SE.getAddExpr(EC, SE.getOne(EC->getType())); - - if (!EC->getType()->isPointerTy() && EC->getType() != CountType) - TripCount = SE.getZeroExtendExpr(TripCount, CountType); + ExitCount = EC; break; } diff --git a/contrib/llvm-project/llvm/lib/CodeGen/HardwareLoops.cpp b/contrib/llvm-project/llvm/lib/CodeGen/HardwareLoops.cpp index 810b10c9c82a..354e50b4844d 100644 --- a/contrib/llvm-project/llvm/lib/CodeGen/HardwareLoops.cpp +++ b/contrib/llvm-project/llvm/lib/CodeGen/HardwareLoops.cpp @@ -187,7 +187,7 @@ namespace { const DataLayout &DL, OptimizationRemarkEmitter *ORE) : SE(SE), DL(DL), ORE(ORE), L(Info.L), M(L->getHeader()->getModule()), - TripCount(Info.TripCount), + ExitCount(Info.ExitCount), CountType(Info.CountType), ExitBranch(Info.ExitBranch), LoopDecrement(Info.LoopDecrement), @@ -202,7 +202,7 @@ namespace { OptimizationRemarkEmitter *ORE = nullptr; Loop *L = nullptr; Module *M = nullptr; - const SCEV *TripCount = nullptr; + const SCEV *ExitCount = nullptr; Type *CountType = nullptr; BranchInst *ExitBranch = nullptr; Value *LoopDecrement = nullptr; @@ -298,7 +298,7 @@ bool HardwareLoops::TryConvertLoop(HardwareLoopInfo &HWLoopInfo) { } assert( - (HWLoopInfo.ExitBlock && HWLoopInfo.ExitBranch && HWLoopInfo.TripCount) && + (HWLoopInfo.ExitBlock && HWLoopInfo.ExitBranch && HWLoopInfo.ExitCount) && "Hardware Loop must have set exit info."); BasicBlock *Preheader = L->getLoopPreheader(); @@ -384,12 +384,18 @@ Value *HardwareLoop::InitLoopCount() { SCEVExpander SCEVE(SE, DL, "loopcnt"); + if (!ExitCount->getType()->isPointerTy() && + ExitCount->getType() != CountType) + ExitCount = SE.getZeroExtendExpr(ExitCount, CountType); + + ExitCount = SE.getAddExpr(ExitCount, SE.getOne(CountType)); + // If we're trying to use the 'test and set' form of the intrinsic, we need // to replace a conditional branch that is controlling entry to the loop. It // is likely (guaranteed?) that the preheader has an unconditional branch to // the loop header, so also check if it has a single predecessor. - if (SE.isLoopEntryGuardedByCond(L, ICmpInst::ICMP_NE, TripCount, - SE.getZero(TripCount->getType()))) { + if (SE.isLoopEntryGuardedByCond(L, ICmpInst::ICMP_NE, ExitCount, + SE.getZero(ExitCount->getType()))) { LLVM_DEBUG(dbgs() << " - Attempting to use test.set counter.\n"); UseLoopGuard |= ForceGuardLoopEntry; } else @@ -401,19 +407,19 @@ Value *HardwareLoop::InitLoopCount() { BasicBlock *Predecessor = BB->getSinglePredecessor(); // If it's not safe to create a while loop then don't force it and create a // do-while loop instead - if (!isSafeToExpandAt(TripCount, Predecessor->getTerminator(), SE)) + if (!isSafeToExpandAt(ExitCount, Predecessor->getTerminator(), SE)) UseLoopGuard = false; else BB = Predecessor; } - if (!isSafeToExpandAt(TripCount, BB->getTerminator(), SE)) { - LLVM_DEBUG(dbgs() << "- Bailing, unsafe to expand TripCount " - << *TripCount << "\n"); + if (!isSafeToExpandAt(ExitCount, BB->getTerminator(), SE)) { + LLVM_DEBUG(dbgs() << "- Bailing, unsafe to expand ExitCount " + << *ExitCount << "\n"); return nullptr; } - Value *Count = SCEVE.expandCodeFor(TripCount, CountType, + Value *Count = SCEVE.expandCodeFor(ExitCount, CountType, BB->getTerminator()); // FIXME: We've expanded Count where we hope to insert the counter setting
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?202109081816.188IGSQu008869>