diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/ConstantHoisting.cpp | 68 | ||||
| -rw-r--r-- | llvm/test/CodeGen/Thumb/consthoist-few-dependents.ll | 191 |
2 files changed, 22 insertions, 237 deletions
diff --git a/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp b/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp index 434fae94703..7acc85c3dd3 100644 --- a/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp +++ b/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp @@ -86,12 +86,6 @@ static cl::opt<bool> ConstHoistGEP( "consthoist-gep", cl::init(false), cl::Hidden, cl::desc("Try hoisting constant gep expressions")); -static cl::opt<unsigned> -MinNumOfDependentToRebase("consthoist-min-num-to-rebase", - cl::desc("Do not rebase if number of dependent constants of a Base is less " - "than this number."), - cl::init(2), cl::Hidden); - namespace { /// The constant hoisting pass. @@ -828,34 +822,7 @@ bool ConstantHoistingPass::emitBaseConstants(GlobalVariable *BaseGV) { unsigned UsesNum = 0; unsigned ReBasesNum = 0; - unsigned NotRebasedNum = 0; for (Instruction *IP : IPSet) { - // First, collect constants depending on this IP of the base. - unsigned Uses = 0; - using RebasedUse = std::tuple<Constant *, Type *, ConstantUser>; - SmallVector<RebasedUse, 4> ToBeRebased; - for (auto const &RCI : ConstInfo.RebasedConstants) { - for (auto const &U : RCI.Uses) { - Uses++; - BasicBlock *OrigMatInsertBB = - findMatInsertPt(U.Inst, U.OpndIdx)->getParent(); - // If Base constant is to be inserted in multiple places, - // generate rebase for U using the Base dominating U. - if (IPSet.size() == 1 || - DT->dominates(IP->getParent(), OrigMatInsertBB)) - ToBeRebased.push_back(RebasedUse(RCI.Offset, RCI.Ty, U)); - } - } - UsesNum = Uses; - - // If only few constants depend on this IP of base, skip rebasing, - // assuming the base and the rebased have the same materialization cost. - if (ToBeRebased.size() < MinNumOfDependentToRebase) { - NotRebasedNum += ToBeRebased.size(); - continue; - } - - // Emit an instance of the base at this IP. Instruction *Base = nullptr; // Hoist and hide the base constant behind a bitcast. if (ConstInfo.BaseExpr) { @@ -873,27 +840,36 @@ bool ConstantHoistingPass::emitBaseConstants(GlobalVariable *BaseGV) { << ") to BB " << IP->getParent()->getName() << '\n' << *Base << '\n'); - // Emit materialization code for rebased constants depending on this IP. - for (auto const &R : ToBeRebased) { - Constant *Off = std::get<0>(R); - Type *Ty = std::get<1>(R); - ConstantUser U = std::get<2>(R); - emitBaseConstants(Base, Off, Ty, U); - ReBasesNum++; - // Use the same debug location as the last user of the constant. - Base->setDebugLoc(DILocation::getMergedLocation( - Base->getDebugLoc(), U.Inst->getDebugLoc())); + // Emit materialization code for all rebased constants. + unsigned Uses = 0; + for (auto const &RCI : ConstInfo.RebasedConstants) { + for (auto const &U : RCI.Uses) { + Uses++; + BasicBlock *OrigMatInsertBB = + findMatInsertPt(U.Inst, U.OpndIdx)->getParent(); + // If Base constant is to be inserted in multiple places, + // generate rebase for U using the Base dominating U. + if (IPSet.size() == 1 || + DT->dominates(Base->getParent(), OrigMatInsertBB)) { + emitBaseConstants(Base, RCI.Offset, RCI.Ty, U); + ReBasesNum++; + } + + Base->setDebugLoc(DILocation::getMergedLocation( + Base->getDebugLoc(), U.Inst->getDebugLoc())); + } } + UsesNum = Uses; + + // Use the same debug location as the last user of the constant. assert(!Base->use_empty() && "The use list is empty!?"); assert(isa<Instruction>(Base->user_back()) && "All uses should be instructions."); } (void)UsesNum; (void)ReBasesNum; - (void)NotRebasedNum; // Expect all uses are rebased after rebase is done. - assert(UsesNum == (ReBasesNum + NotRebasedNum) && - "Not all uses are rebased"); + assert(UsesNum == ReBasesNum && "Not all uses are rebased"); NumConstantsHoisted++; diff --git a/llvm/test/CodeGen/Thumb/consthoist-few-dependents.ll b/llvm/test/CodeGen/Thumb/consthoist-few-dependents.ll deleted file mode 100644 index 151c9acea5f..00000000000 --- a/llvm/test/CodeGen/Thumb/consthoist-few-dependents.ll +++ /dev/null @@ -1,191 +0,0 @@ -; RUN: opt -consthoist -S %s -o - | FileCheck %s --check-prefix=OPT -; RUN: opt -consthoist -S -consthoist-min-num-to-rebase=1 %s -o - | FileCheck %s --check-prefix=OPT --check-prefix=OPT-1 -; RUN: opt -consthoist -S -consthoist-min-num-to-rebase=2 %s -o - | FileCheck %s --check-prefix=OPT --check-prefix=OPT-2 -; RUN: opt -consthoist -S -consthoist-min-num-to-rebase=3 %s -o - | FileCheck %s --check-prefix=OPT --check-prefix=OPT-3 - -; RUN: llc %s -o - | FileCheck %s --check-prefix=LLC - -target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64" -target triple = "thumbv6m-none-unknown-musleabi" - -; Test that constant 0 and 1 of i1 type is NOT hoisted due low -; materializing cost. - -; OPT-LABEL: avalon -; OPT: bb1: -; OPT: store i1 true -; OPT: bb2: -; OPT: store i1 false -; OPT: bb3: -; OPT: store i1 false -; OPT: store i1 false -; OPT-NOT: add - -; LLC-LABEL: avalon -; LLC-DAG: movs r{{[0-9]+}}, #0 -; LLC-DAG: movs r{{[0-9]+}}, #0 -; LLC-DAG: movs r{{[0-9]+}}, #1 -; LLC-NOT: add - -@global = local_unnamed_addr global i1 undef, align 1 -@global.0 = local_unnamed_addr global i1 undef, align 1 - -define void @avalon() #0 { -bb: - switch i8 undef, label %bb5 [ - i8 0, label %bb1 - i8 -1, label %bb2 - i8 1, label %bb3 - ] - -bb1: - store i1 1, i1* @global, align 1 - unreachable - -bb2: - store i1 0, i1* @global, align 1 - unreachable - -bb3: - store i1 0, i1* @global.0, align 1 - store i1 0, i1* @global, align 1 - unreachable - -bb5: - ret void -} - -; Test that for i8 type, constant -1 is not rebased since it's the only -; dependent of base constant -2. -; This test is also covered by r342898, see -; test/CodeGen/Thumb/consthoist-imm8-costs-1.ll - -; OPT-LABEL: barney -; OPT: bb1: -; OPT: store i8 -1 -; OPT: bb2: -; OPT: store i8 -2 -; OPT: bb3: -; OPT: store i8 -2 -; OPT: store i8 -2 -; OPT-NOT: add - -; LLC-LABEL: barney -; LLC-DAG: movs r{{[0-9]+}}, #254 -; LLC-DAG: movs r{{[0-9]+}}, #255 -; LLC-NOT: mvn -; LLC-NOT: add - -@global.1 = local_unnamed_addr global i8 undef, align 1 -@global.2 = local_unnamed_addr global i8 undef, align 1 - -define void @barney() #0 { -bb: - switch i8 undef, label %bb5 [ - i8 0, label %bb1 - i8 -1, label %bb2 - i8 1, label %bb3 - ] - -bb1: ; preds = %bb - store i8 -1, i8* @global.1, align 1 - unreachable - -bb2: ; preds = %bb - store i8 -2, i8* @global.1, align 1 - unreachable - -bb3: ; preds = %bb - store i8 -2, i8* @global.2, align 1 - store i8 -2, i8* @global.1, align 1 - unreachable - -bb5: ; preds = %bb - ret void -} - -; Test that for i16 type constant 65532 is not rebased if it's the only -; dependent of base constant 65531. Cost would be the same if rebased. -; If rebased, 3 two-byte instructions: -; movs r0, #4 -; mvns r0, r0 -; adds r0, r0, #1 -; If NOT rebased, 1 two-byte instruction plus 1 four-byte CP entry: -; ldr r1, .LCPI2_3 -; ... -; .LCPI2_3: -; .long 65532 - -; OPT-LABEL: carla - -; -consthoist-min-num-to-rebase=1, check that 65532 and single use of 65531 -; in bb2 is rebased -; OPT-1: bb1: -; OPT-1: %[[C1:const[0-9]?]] = bitcast i16 -5 to i16 -; OPT-1-NEXT: %const_mat = add i16 %[[C1]], 1 -; OPT-1-NEXT: store i16 %const_mat, i16* @global.3, align 1 -; OPT-1: bb2: -; OPT-1-NEXT: %[[C2:const[0-9]?]] = bitcast i16 -5 to i16 -; OPT-1-NEXT: store i16 %[[C2]], i16* @global.3, align 1 -; OPT-1: bb3: -; OPT-1-NEXT: %[[C3:const[0-9]?]] = bitcast i16 -5 to i16 -; OPT-1-NEXT: store i16 %[[C3]], i16* @global.4, align 1 -; OPT-1-NEXT: store i16 %[[C3]], i16* @global.3, align 1 - -; -consthoist-min-num-to-rebase=2, check that 65532 and single use of 65531 -; in bb2 is not rebased -; OPT-2: bb1: -; OPT-2-NEXT: store i16 -4, i16* @global.3, align 1 -; OPT-2: bb2: -; OPT-2-NEXT: store i16 -5, i16* @global.3, align 1 -; OPT-2: bb3: -; OPT-2-NEXT: %[[C4:const[0-9]?]] = bitcast i16 -5 to i16 -; OPT-2-NEXT: store i16 %[[C4]], i16* @global.4, align 1 -; OPT-2-NEXT: store i16 %[[C4]], i16* @global.3, align 1 -; OPT-2-NOT: add - -; -consthoist-min-num-to-rebase=3, check that dual uses of 65531 in bb3 are -; not rebase -; OPT-3: bb1: -; OPT-3-NEXT: store i16 -4, i16* @global.3, align 1 -; OPT-3: bb2: -; OPT-3-NEXT: store i16 -5, i16* @global.3, align 1 -; OPT-3: bb3: -; OPT-3-NEXT: store i16 -5, i16* @global.4, align 1 -; OPT-3-NEXT: store i16 -5, i16* @global.3, align 1 -; OPT-3-NOT: add -; OPT-3-NOT: bitcast - -; LLC-LABEL: carla -; LLC-DAG: ldr r{{[0-9]+}}, .LCPI2_1 -; LLC-DAG: ldr r{{[0-9]+}}, .LCPI2_3 -; LLC-NOT: mvn -; LLC-NOT: add - -@global.3 = local_unnamed_addr global i16 undef, align 2 -@global.4 = local_unnamed_addr global i16 undef, align 2 - -define void @carla() { -bb: - switch i8 undef, label %bb5 [ - i8 0, label %bb1 - i8 -1, label %bb2 - i8 1, label %bb3 - ] - -bb1: ; preds = %bb - store i16 65532, i16* @global.3, align 1 - unreachable - -bb2: ; preds = %bb - store i16 65531, i16* @global.3, align 1 - unreachable - -bb3: ; preds = %bb - store i16 65531, i16* @global.4, align 1 - store i16 65531, i16* @global.3, align 1 - unreachable - -bb5: ; preds = %bb - ret void -} |
