From 435798e96a64738b55a01055dde1bc9a88a15191 Mon Sep 17 00:00:00 2001 From: Hal Finkel Date: Wed, 28 Aug 2013 18:33:10 +0000 Subject: [PATCH] Disable unrolling in the loop vectorizer when disabled in the pass manager When unrolling is disabled in the pass manager, the loop vectorizer should also not unroll loops. This will allow the -fno-unroll-loops option in Clang to behave as expected (even for vectorizable loops). The loop vectorizer's -force-vector-unroll option will (continue to) override the pass-manager setting (including -force-vector-unroll=0 to force use of the internal auto-selection logic). In order to test this, I added a flag to opt (-disable-loop-unrolling) to force disable unrolling through opt (the analog of -fno-unroll-loops in Clang). Also, this fixes a small bug in opt where the loop vectorizer was enabled only after the pass manager populated the queue of passes (the global_alias.ll test needed a slight update to the RUN line as a result of this fix). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189499 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Transforms/Vectorize.h | 2 +- lib/Transforms/IPO/PassManagerBuilder.cpp | 4 +-- lib/Transforms/Vectorize/LoopVectorize.cpp | 17 ++++++---- .../Transforms/LoopVectorize/X86/unroll-pm.ll | 31 +++++++++++++++++++ test/Transforms/LoopVectorize/global_alias.ll | 2 +- tools/opt/opt.cpp | 12 +++++-- 6 files changed, 55 insertions(+), 13 deletions(-) create mode 100644 test/Transforms/LoopVectorize/X86/unroll-pm.ll diff --git a/include/llvm/Transforms/Vectorize.h b/include/llvm/Transforms/Vectorize.h index 8d0db161160..823c5fba745 100644 --- a/include/llvm/Transforms/Vectorize.h +++ b/include/llvm/Transforms/Vectorize.h @@ -114,7 +114,7 @@ createBBVectorizePass(const VectorizeConfig &C = VectorizeConfig()); // // LoopVectorize - Create a loop vectorization pass. // -Pass *createLoopVectorizePass(); +Pass *createLoopVectorizePass(bool NoUnrolling = false); //===----------------------------------------------------------------------===// // diff --git a/lib/Transforms/IPO/PassManagerBuilder.cpp b/lib/Transforms/IPO/PassManagerBuilder.cpp index 743dc423434..d4c0c2caeaa 100644 --- a/lib/Transforms/IPO/PassManagerBuilder.cpp +++ b/lib/Transforms/IPO/PassManagerBuilder.cpp @@ -196,7 +196,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) { MPM.add(createLoopDeletionPass()); // Delete dead loops if (!LateVectorize && LoopVectorize) - MPM.add(createLoopVectorizePass()); + MPM.add(createLoopVectorizePass(DisableUnrollLoops)); if (!DisableUnrollLoops) MPM.add(createLoopUnrollPass()); // Unroll small loops @@ -250,7 +250,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) { // Add the various vectorization passes and relevant cleanup passes for // them since we are no longer in the middle of the main scalar pipeline. if (LoopVectorize) { - MPM.add(createLoopVectorizePass()); + MPM.add(createLoopVectorizePass(DisableUnrollLoops)); if (!DisableUnrollLoops) MPM.add(createLoopUnrollPass()); // Unroll small loops diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp index 2ee1441e4b5..0afc73e5098 100644 --- a/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -761,9 +761,9 @@ struct LoopVectorizeHints { /// Vectorization unroll factor. unsigned Unroll; - LoopVectorizeHints(const Loop *L) + LoopVectorizeHints(const Loop *L, bool DisableUnrolling) : Width(VectorizationFactor) - , Unroll(VectorizationUnroll) + , Unroll(DisableUnrolling ? 1 : VectorizationUnroll) , LoopID(L->getLoopID()) { getHints(L); // The command line options override any loop metadata except for when @@ -772,6 +772,9 @@ struct LoopVectorizeHints { Width = VectorizationFactor; if (VectorizationUnroll.getNumOccurrences() > 0) Unroll = VectorizationUnroll; + + DEBUG(if (DisableUnrolling && Unroll == 1) + dbgs() << "LV: Unrolling disabled by the pass manager\n"); } /// Return the loop vectorizer metadata prefix. @@ -878,7 +881,8 @@ struct LoopVectorize : public LoopPass { /// Pass identification, replacement for typeid static char ID; - explicit LoopVectorize() : LoopPass(ID) { + explicit LoopVectorize(bool NoUnrolling = false) + : LoopPass(ID), DisableUnrolling(NoUnrolling) { initializeLoopVectorizePass(*PassRegistry::getPassRegistry()); } @@ -888,6 +892,7 @@ struct LoopVectorize : public LoopPass { TargetTransformInfo *TTI; DominatorTree *DT; TargetLibraryInfo *TLI; + bool DisableUnrolling; virtual bool runOnLoop(Loop *L, LPPassManager &LPM) { // We only vectorize innermost loops. @@ -909,7 +914,7 @@ struct LoopVectorize : public LoopPass { DEBUG(dbgs() << "LV: Checking a loop in \"" << L->getHeader()->getParent()->getName() << "\"\n"); - LoopVectorizeHints Hints(L); + LoopVectorizeHints Hints(L, DisableUnrolling); if (Hints.Width == 1 && Hints.Unroll == 1) { DEBUG(dbgs() << "LV: Not vectorizing.\n"); @@ -4786,8 +4791,8 @@ INITIALIZE_PASS_DEPENDENCY(LoopSimplify) INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false) namespace llvm { - Pass *createLoopVectorizePass() { - return new LoopVectorize(); + Pass *createLoopVectorizePass(bool NoUnrolling) { + return new LoopVectorize(NoUnrolling); } } diff --git a/test/Transforms/LoopVectorize/X86/unroll-pm.ll b/test/Transforms/LoopVectorize/X86/unroll-pm.ll new file mode 100644 index 00000000000..5064fec286c --- /dev/null +++ b/test/Transforms/LoopVectorize/X86/unroll-pm.ll @@ -0,0 +1,31 @@ +; RUN: opt < %s -O2 -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=4 -S | FileCheck %s +; RUN: opt < %s -O2 -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=4 -disable-loop-unrolling -S | FileCheck %s -check-prefix=CHECK-NOUNRL + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.8.0" +;CHECK-LABEL: @bar( +;CHECK: store <4 x i32> +;CHECK: store <4 x i32> +;CHECK: ret +;CHECK-NOUNRL-LABEL: @bar( +;CHECK-NOUNRL: store <4 x i32> +;CHECK-NOUNRL-NOT: store <4 x i32> +;CHECK-NOUNRL: ret +define i32 @bar(i32* nocapture %A, i32 %n) nounwind uwtable ssp { + %1 = icmp sgt i32 %n, 0 + br i1 %1, label %.lr.ph, label %._crit_edge + +.lr.ph: ; preds = %0, %.lr.ph + %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ] + %2 = getelementptr inbounds i32* %A, i64 %indvars.iv + %3 = load i32* %2, align 4 + %4 = add nsw i32 %3, 6 + store i32 %4, i32* %2, align 4 + %indvars.iv.next = add i64 %indvars.iv, 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp eq i32 %lftr.wideiv, %n + br i1 %exitcond, label %._crit_edge, label %.lr.ph + +._crit_edge: ; preds = %.lr.ph, %0 + ret i32 undef +} diff --git a/test/Transforms/LoopVectorize/global_alias.ll b/test/Transforms/LoopVectorize/global_alias.ll index ae72d3c6082..4fd4c989de4 100644 --- a/test/Transforms/LoopVectorize/global_alias.ll +++ b/test/Transforms/LoopVectorize/global_alias.ll @@ -1,4 +1,4 @@ -; RUN: opt < %s -O3 -loop-vectorize -force-vector-unroll=1 -force-vector-width=4 -dce -instcombine -S | FileCheck %s +; RUN: opt < %s -O1 -loop-vectorize -force-vector-unroll=1 -force-vector-width=4 -dce -instcombine -S | FileCheck %s target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:64:128-a0:0:64-n32-S64" diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp index ca820617861..691080aba37 100644 --- a/tools/opt/opt.cpp +++ b/tools/opt/opt.cpp @@ -135,6 +135,11 @@ UnitAtATime("funit-at-a-time", cl::desc("Enable IPO. This is same as llvm-gcc's -funit-at-a-time"), cl::init(true)); +static cl::opt +DisableLoopUnrolling("disable-loop-unrolling", + cl::desc("Disable loop unrolling in all relevant passes"), + cl::init(false)); + static cl::opt DisableSimplifyLibCalls("disable-simplify-libcalls", cl::desc("Disable simplify-libcalls")); @@ -447,12 +452,13 @@ static void AddOptimizationPasses(PassManagerBase &MPM,FunctionPassManager &FPM, Builder.Inliner = createAlwaysInlinerPass(); } Builder.DisableUnitAtATime = !UnitAtATime; - Builder.DisableUnrollLoops = OptLevel == 0; + Builder.DisableUnrollLoops = (DisableLoopUnrolling.getNumOccurrences() > 0) ? + DisableLoopUnrolling : OptLevel == 0; + Builder.LoopVectorize = OptLevel > 1 && SizeLevel < 2; + Builder.populateFunctionPassManager(FPM); Builder.populateModulePassManager(MPM); - - Builder.LoopVectorize = OptLevel > 1 && SizeLevel < 2; } static void AddStandardCompilePasses(PassManagerBase &PM) {