forked from OSchip/llvm-project
Revert "[ConstHoist] Do not rebase single (or few) dependent constant"
This caused a couple test failures on a bot: CodeGen/X86/constant-hoisting-bfi.ll Transforms/ConstantHoisting/X86/ehpad.ll Example: http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-incremental/53575/ llvm-svn: 343005
This commit is contained in:
Jessica Paquette
parent
349b5943b4
commit
e02de05b32
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@ -86,12 +86,6 @@ static cl::opt<bool> ConstHoistGEP(
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"consthoist-gep", cl::init(false), cl::Hidden,
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cl::desc("Try hoisting constant gep expressions"));
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static cl::opt<unsigned>
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MinNumOfDependentToRebase("consthoist-min-num-to-rebase",
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cl::desc("Do not rebase if number of dependent constants of a Base is less "
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"than this number."),
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cl::init(2), cl::Hidden);
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namespace {
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/// The constant hoisting pass.
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@ -828,34 +822,7 @@ bool ConstantHoistingPass::emitBaseConstants(GlobalVariable *BaseGV) {
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unsigned UsesNum = 0;
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unsigned ReBasesNum = 0;
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unsigned NotRebasedNum = 0;
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for (Instruction *IP : IPSet) {
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// First, collect constants depending on this IP of the base.
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unsigned Uses = 0;
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using RebasedUse = std::tuple<Constant *, Type *, ConstantUser>;
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SmallVector<RebasedUse, 4> ToBeRebased;
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for (auto const &RCI : ConstInfo.RebasedConstants) {
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for (auto const &U : RCI.Uses) {
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Uses++;
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BasicBlock *OrigMatInsertBB =
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findMatInsertPt(U.Inst, U.OpndIdx)->getParent();
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// If Base constant is to be inserted in multiple places,
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// generate rebase for U using the Base dominating U.
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if (IPSet.size() == 1 ||
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DT->dominates(IP->getParent(), OrigMatInsertBB))
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ToBeRebased.push_back(RebasedUse(RCI.Offset, RCI.Ty, U));
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}
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}
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UsesNum = Uses;
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// If only few constants depend on this IP of base, skip rebasing,
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// assuming the base and the rebased have the same materialization cost.
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if (ToBeRebased.size() < MinNumOfDependentToRebase) {
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NotRebasedNum += ToBeRebased.size();
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continue;
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}
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// Emit an instance of the base at this IP.
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Instruction *Base = nullptr;
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// Hoist and hide the base constant behind a bitcast.
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if (ConstInfo.BaseExpr) {
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@ -873,27 +840,36 @@ bool ConstantHoistingPass::emitBaseConstants(GlobalVariable *BaseGV) {
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<< ") to BB " << IP->getParent()->getName() << '\n'
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<< *Base << '\n');
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// Emit materialization code for rebased constants depending on this IP.
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for (auto const &R : ToBeRebased) {
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Constant *Off = std::get<0>(R);
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Type *Ty = std::get<1>(R);
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ConstantUser U = std::get<2>(R);
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emitBaseConstants(Base, Off, Ty, U);
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ReBasesNum++;
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// Use the same debug location as the last user of the constant.
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Base->setDebugLoc(DILocation::getMergedLocation(
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Base->getDebugLoc(), U.Inst->getDebugLoc()));
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// Emit materialization code for all rebased constants.
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unsigned Uses = 0;
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for (auto const &RCI : ConstInfo.RebasedConstants) {
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for (auto const &U : RCI.Uses) {
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Uses++;
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BasicBlock *OrigMatInsertBB =
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findMatInsertPt(U.Inst, U.OpndIdx)->getParent();
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// If Base constant is to be inserted in multiple places,
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// generate rebase for U using the Base dominating U.
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if (IPSet.size() == 1 ||
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DT->dominates(Base->getParent(), OrigMatInsertBB)) {
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emitBaseConstants(Base, RCI.Offset, RCI.Ty, U);
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ReBasesNum++;
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}
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Base->setDebugLoc(DILocation::getMergedLocation(
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Base->getDebugLoc(), U.Inst->getDebugLoc()));
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}
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}
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UsesNum = Uses;
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// Use the same debug location as the last user of the constant.
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assert(!Base->use_empty() && "The use list is empty!?");
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assert(isa<Instruction>(Base->user_back()) &&
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"All uses should be instructions.");
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}
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(void)UsesNum;
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(void)ReBasesNum;
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(void)NotRebasedNum;
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// Expect all uses are rebased after rebase is done.
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assert(UsesNum == (ReBasesNum + NotRebasedNum) &&
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"Not all uses are rebased");
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assert(UsesNum == ReBasesNum && "Not all uses are rebased");
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NumConstantsHoisted++;
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@ -1,191 +0,0 @@
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; RUN: opt -consthoist -S %s -o - | FileCheck %s --check-prefix=OPT
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; RUN: opt -consthoist -S -consthoist-min-num-to-rebase=1 %s -o - | FileCheck %s --check-prefix=OPT --check-prefix=OPT-1
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; RUN: opt -consthoist -S -consthoist-min-num-to-rebase=2 %s -o - | FileCheck %s --check-prefix=OPT --check-prefix=OPT-2
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; RUN: opt -consthoist -S -consthoist-min-num-to-rebase=3 %s -o - | FileCheck %s --check-prefix=OPT --check-prefix=OPT-3
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; RUN: llc %s -o - | FileCheck %s --check-prefix=LLC
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target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
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target triple = "thumbv6m-none-unknown-musleabi"
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; Test that constant 0 and 1 of i1 type is NOT hoisted due low
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; materializing cost.
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; OPT-LABEL: avalon
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; OPT: bb1:
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; OPT: store i1 true
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; OPT: bb2:
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; OPT: store i1 false
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; OPT: bb3:
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; OPT: store i1 false
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; OPT: store i1 false
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; OPT-NOT: add
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; LLC-LABEL: avalon
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; LLC-DAG: movs r{{[0-9]+}}, #0
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; LLC-DAG: movs r{{[0-9]+}}, #0
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; LLC-DAG: movs r{{[0-9]+}}, #1
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; LLC-NOT: add
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@global = local_unnamed_addr global i1 undef, align 1
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@global.0 = local_unnamed_addr global i1 undef, align 1
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define void @avalon() #0 {
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bb:
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switch i8 undef, label %bb5 [
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i8 0, label %bb1
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i8 -1, label %bb2
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i8 1, label %bb3
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]
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bb1:
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store i1 1, i1* @global, align 1
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unreachable
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bb2:
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store i1 0, i1* @global, align 1
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unreachable
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bb3:
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store i1 0, i1* @global.0, align 1
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store i1 0, i1* @global, align 1
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unreachable
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bb5:
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ret void
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}
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; Test that for i8 type, constant -1 is not rebased since it's the only
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; dependent of base constant -2.
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; This test is also covered by r342898, see
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; test/CodeGen/Thumb/consthoist-imm8-costs-1.ll
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; OPT-LABEL: barney
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; OPT: bb1:
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; OPT: store i8 -1
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; OPT: bb2:
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; OPT: store i8 -2
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; OPT: bb3:
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; OPT: store i8 -2
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; OPT: store i8 -2
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; OPT-NOT: add
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; LLC-LABEL: barney
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; LLC-DAG: movs r{{[0-9]+}}, #254
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; LLC-DAG: movs r{{[0-9]+}}, #255
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; LLC-NOT: mvn
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; LLC-NOT: add
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@global.1 = local_unnamed_addr global i8 undef, align 1
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@global.2 = local_unnamed_addr global i8 undef, align 1
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define void @barney() #0 {
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bb:
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switch i8 undef, label %bb5 [
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i8 0, label %bb1
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i8 -1, label %bb2
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i8 1, label %bb3
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]
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bb1: ; preds = %bb
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store i8 -1, i8* @global.1, align 1
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unreachable
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bb2: ; preds = %bb
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store i8 -2, i8* @global.1, align 1
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unreachable
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bb3: ; preds = %bb
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store i8 -2, i8* @global.2, align 1
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store i8 -2, i8* @global.1, align 1
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unreachable
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bb5: ; preds = %bb
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ret void
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}
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; Test that for i16 type constant 65532 is not rebased if it's the only
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; dependent of base constant 65531. Cost would be the same if rebased.
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; If rebased, 3 two-byte instructions:
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; movs r0, #4
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; mvns r0, r0
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; adds r0, r0, #1
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; If NOT rebased, 1 two-byte instruction plus 1 four-byte CP entry:
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; ldr r1, .LCPI2_3
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; ...
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; .LCPI2_3:
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; .long 65532
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; OPT-LABEL: carla
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; -consthoist-min-num-to-rebase=1, check that 65532 and single use of 65531
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; in bb2 is rebased
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; OPT-1: bb1:
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; OPT-1: %[[C1:const[0-9]?]] = bitcast i16 -5 to i16
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; OPT-1-NEXT: %const_mat = add i16 %[[C1]], 1
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; OPT-1-NEXT: store i16 %const_mat, i16* @global.3, align 1
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; OPT-1: bb2:
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; OPT-1-NEXT: %[[C2:const[0-9]?]] = bitcast i16 -5 to i16
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; OPT-1-NEXT: store i16 %[[C2]], i16* @global.3, align 1
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; OPT-1: bb3:
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; OPT-1-NEXT: %[[C3:const[0-9]?]] = bitcast i16 -5 to i16
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; OPT-1-NEXT: store i16 %[[C3]], i16* @global.4, align 1
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; OPT-1-NEXT: store i16 %[[C3]], i16* @global.3, align 1
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; -consthoist-min-num-to-rebase=2, check that 65532 and single use of 65531
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; in bb2 is not rebased
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; OPT-2: bb1:
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; OPT-2-NEXT: store i16 -4, i16* @global.3, align 1
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; OPT-2: bb2:
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; OPT-2-NEXT: store i16 -5, i16* @global.3, align 1
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; OPT-2: bb3:
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; OPT-2-NEXT: %[[C4:const[0-9]?]] = bitcast i16 -5 to i16
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; OPT-2-NEXT: store i16 %[[C4]], i16* @global.4, align 1
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; OPT-2-NEXT: store i16 %[[C4]], i16* @global.3, align 1
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; OPT-2-NOT: add
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; -consthoist-min-num-to-rebase=3, check that dual uses of 65531 in bb3 are
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; not rebase
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; OPT-3: bb1:
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; OPT-3-NEXT: store i16 -4, i16* @global.3, align 1
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; OPT-3: bb2:
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; OPT-3-NEXT: store i16 -5, i16* @global.3, align 1
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; OPT-3: bb3:
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; OPT-3-NEXT: store i16 -5, i16* @global.4, align 1
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; OPT-3-NEXT: store i16 -5, i16* @global.3, align 1
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; OPT-3-NOT: add
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; OPT-3-NOT: bitcast
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; LLC-LABEL: carla
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; LLC-DAG: ldr r{{[0-9]+}}, .LCPI2_1
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; LLC-DAG: ldr r{{[0-9]+}}, .LCPI2_3
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; LLC-NOT: mvn
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; LLC-NOT: add
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@global.3 = local_unnamed_addr global i16 undef, align 2
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@global.4 = local_unnamed_addr global i16 undef, align 2
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define void @carla() {
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bb:
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switch i8 undef, label %bb5 [
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i8 0, label %bb1
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i8 -1, label %bb2
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i8 1, label %bb3
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]
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bb1: ; preds = %bb
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store i16 65532, i16* @global.3, align 1
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unreachable
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bb2: ; preds = %bb
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store i16 65531, i16* @global.3, align 1
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unreachable
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bb3: ; preds = %bb
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store i16 65531, i16* @global.4, align 1
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store i16 65531, i16* @global.3, align 1
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unreachable
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bb5: ; preds = %bb
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ret void
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}
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