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-rw-r--r--include/llvm/Target/TargetTransformImpl.h2
-rw-r--r--include/llvm/TargetTransformInfo.h5
-rw-r--r--include/llvm/Transforms/Utils/Local.h4
-rw-r--r--lib/Target/TargetTransformImpl.cpp7
-rw-r--r--lib/Transforms/Scalar/CodeGenPrepare.cpp114
-rw-r--r--lib/Transforms/Scalar/SimplifyCFGPass.cpp12
-rw-r--r--lib/Transforms/Utils/SimplifyCFG.cpp21
-rw-r--r--test/CodeGen/SPARC/load_to_switch.ll84
-rw-r--r--test/Transforms/SimplifyCFG/SPARC/lit.local.cfg6
-rw-r--r--test/Transforms/SimplifyCFG/SPARC/switch_to_lookup_table.ll32
10 files changed, 79 insertions, 208 deletions
diff --git a/include/llvm/Target/TargetTransformImpl.h b/include/llvm/Target/TargetTransformImpl.h
index fd4b737..fa1acbe 100644
--- a/include/llvm/Target/TargetTransformImpl.h
+++ b/include/llvm/Target/TargetTransformImpl.h
@@ -46,6 +46,8 @@ public:
virtual unsigned getJumpBufAlignment() const;
virtual unsigned getJumpBufSize() const;
+
+ virtual bool shouldBuildLookupTables() const;
};
class VectorTargetTransformImpl : public VectorTargetTransformInfo {
diff --git a/include/llvm/TargetTransformInfo.h b/include/llvm/TargetTransformInfo.h
index 6ee3b37..c65ef17 100644
--- a/include/llvm/TargetTransformInfo.h
+++ b/include/llvm/TargetTransformInfo.h
@@ -117,6 +117,11 @@ public:
virtual unsigned getJumpBufSize() const {
return 0;
}
+ /// shouldBuildLookupTables - Return true if switches should be turned into
+ /// lookup tables for the target.
+ virtual bool shouldBuildLookupTables() const {
+ return true;
+ }
};
/// VectorTargetTransformInfo - This interface is used by the vectorizers
diff --git a/include/llvm/Transforms/Utils/Local.h b/include/llvm/Transforms/Utils/Local.h
index 49eeb57..5c804d8 100644
--- a/include/llvm/Transforms/Utils/Local.h
+++ b/include/llvm/Transforms/Utils/Local.h
@@ -37,6 +37,7 @@ class AllocaInst;
class ConstantExpr;
class DataLayout;
class TargetLibraryInfo;
+class TargetTransformInfo;
class DIBuilder;
template<typename T> class SmallVectorImpl;
@@ -134,7 +135,8 @@ bool EliminateDuplicatePHINodes(BasicBlock *BB);
/// of the CFG. It returns true if a modification was made, possibly deleting
/// the basic block that was pointed to.
///
-bool SimplifyCFG(BasicBlock *BB, const DataLayout *TD = 0);
+bool SimplifyCFG(BasicBlock *BB, const DataLayout *TD = 0,
+ const TargetTransformInfo *TTI = 0);
/// FoldBranchToCommonDest - If this basic block is ONLY a setcc and a branch,
/// and if a predecessor branches to us and one of our successors, fold the
diff --git a/lib/Target/TargetTransformImpl.cpp b/lib/Target/TargetTransformImpl.cpp
index 27877a9..38c704f 100644
--- a/lib/Target/TargetTransformImpl.cpp
+++ b/lib/Target/TargetTransformImpl.cpp
@@ -49,6 +49,12 @@ unsigned ScalarTargetTransformImpl::getJumpBufSize() const {
return TLI->getJumpBufSize();
}
+bool ScalarTargetTransformImpl::shouldBuildLookupTables() const {
+ return TLI->supportJumpTables() &&
+ (TLI->isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) ||
+ TLI->isOperationLegalOrCustom(ISD::BRIND, MVT::Other));
+}
+
//===----------------------------------------------------------------------===//
//
// Calls used by the vectorizers.
@@ -313,4 +319,3 @@ VectorTargetTransformImpl::getNumberOfParts(Type *Tp) const {
getTypeLegalizationCost(Tp->getContext(), TLI->getValueType(Tp));
return LT.first;
}
-
diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index 74e310f..9cd5381 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -18,7 +18,6 @@
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
-#include "llvm/GlobalVariable.h"
#include "llvm/IRBuilder.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
@@ -128,7 +127,6 @@ namespace {
bool OptimizeSelectInst(SelectInst *SI);
bool DupRetToEnableTailCallOpts(ReturnInst *RI);
bool PlaceDbgValues(Function &F);
- bool ConvertLoadToSwitch(LoadInst *LI);
};
}
@@ -1292,11 +1290,9 @@ bool CodeGenPrepare::OptimizeInst(Instruction *I) {
return OptimizeCmpExpression(CI);
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
- bool Changed = false;
if (TLI)
- Changed |= OptimizeMemoryInst(I, I->getOperand(0), LI->getType());
- Changed |= ConvertLoadToSwitch(LI);
- return Changed;
+ return OptimizeMemoryInst(I, I->getOperand(0), LI->getType());
+ return false;
}
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
@@ -1376,109 +1372,3 @@ bool CodeGenPrepare::PlaceDbgValues(Function &F) {
}
return MadeChange;
}
-
-static bool TargetSupportsJumpTables(const TargetLowering &TLI) {
- return TLI.supportJumpTables() &&
- (TLI.isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) ||
- TLI.isOperationLegalOrCustom(ISD::BRIND, MVT::Other));
-}
-
-/// ConvertLoadToSwitch - Convert loads from constant lookup tables into
-/// switches. This undos the switch-to-lookup table transformation in
-/// SimplifyCFG for targets where that is inprofitable.
-bool CodeGenPrepare::ConvertLoadToSwitch(LoadInst *LI) {
- // This only applies to targets that don't support jump tables.
- if (!TLI || TargetSupportsJumpTables(*TLI))
- return false;
-
- // FIXME: In the future, it would be desirable to have enough target
- // information in SimplifyCFG, so we could decide at that stage whether to
- // transform the switch to a lookup table or not, and this
- // reverse-transformation could be removed.
-
- GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getPointerOperand());
- if (!GEP || !GEP->isInBounds() || GEP->getPointerAddressSpace())
- return false;
- if (GEP->getNumIndices() != 2)
- return false;
- Value *FirstIndex = GEP->idx_begin()[0];
- ConstantInt *FirstIndexInt = dyn_cast<ConstantInt>(FirstIndex);
- if (!FirstIndexInt || !FirstIndexInt->isZero())
- return false;
-
- Value *TableIndex = GEP->idx_begin()[1];
- IntegerType *TableIndexTy = cast<IntegerType>(TableIndex->getType());
-
- GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getPointerOperand());
- if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer())
- return false;
-
- Constant *Arr = GV->getInitializer();
- uint64_t NumElements;
- if (ConstantArray *CA = dyn_cast<ConstantArray>(Arr))
- NumElements = CA->getType()->getNumElements();
- else if (ConstantDataArray *CDA = dyn_cast<ConstantDataArray>(Arr))
- NumElements = CDA->getNumElements();
- else
- return false;
- if (NumElements < 2)
- return false;
-
- // Split the block.
- BasicBlock *OriginalBB = LI->getParent();
- BasicBlock *PostSwitchBB = OriginalBB->splitBasicBlock(LI);
-
- // Replace OriginalBB's terminator with a switch.
- IRBuilder<> Builder(OriginalBB->getTerminator());
- SwitchInst *Switch = Builder.CreateSwitch(TableIndex, PostSwitchBB,
- NumElements - 1);
- OriginalBB->getTerminator()->eraseFromParent();
-
- // Count the frequency of each value to decide which to use as default.
- SmallDenseMap<Constant*, uint64_t> ValueFreq;
- for (uint64_t I = 0; I < NumElements; ++I)
- ++ValueFreq[Arr->getAggregateElement(I)];
- uint64_t MaxCount = 0;
- Constant *DefaultValue = NULL;
- for (SmallDenseMap<Constant*, uint64_t>::iterator I = ValueFreq.begin(),
- E = ValueFreq.end(); I != E; ++I) {
- if (I->second > MaxCount) {
- MaxCount = I->second;
- DefaultValue = I->first;
- }
- }
- assert(DefaultValue && "No values in the array?");
-
- // Create the phi node in PostSwitchBB, which will replace the load.
- Builder.SetInsertPoint(PostSwitchBB->begin());
- PHINode *PHI = Builder.CreatePHI(LI->getType(), NumElements);
- PHI->addIncoming(DefaultValue, OriginalBB);
-
- // Build basic blocks to target with the switch.
- for (uint64_t I = 0; I < NumElements; ++I) {
- Constant *C = Arr->getAggregateElement(I);
- if (C == DefaultValue) continue; // Already covered by the default case.
-
- BasicBlock *BB = BasicBlock::Create(PostSwitchBB->getContext(),
- "lookup.bb",
- PostSwitchBB->getParent(),
- PostSwitchBB);
- Switch->addCase(ConstantInt::get(TableIndexTy, I), BB);
- Builder.SetInsertPoint(BB);
- Builder.CreateBr(PostSwitchBB);
- PHI->addIncoming(C, BB);
- }
-
- // Remove the load.
- LI->replaceAllUsesWith(PHI);
- LI->eraseFromParent();
-
- // Clean up.
- if (GEP->use_empty())
- GEP->eraseFromParent();
- if (GV->hasUnnamedAddr() && GV->hasPrivateLinkage() && GV->use_empty())
- GV->eraseFromParent();
-
- CurInstIterator = Switch;
- return true;
-}
diff --git a/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index 84b820b..9f24bb6 100644
--- a/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -35,6 +35,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/TargetTransformInfo.h"
using namespace llvm;
STATISTIC(NumSimpl, "Number of blocks simplified");
@@ -293,7 +294,8 @@ static bool mergeEmptyReturnBlocks(Function &F) {
/// iterativelySimplifyCFG - Call SimplifyCFG on all the blocks in the function,
/// iterating until no more changes are made.
-static bool iterativelySimplifyCFG(Function &F, const DataLayout *TD) {
+static bool iterativelySimplifyCFG(Function &F, const DataLayout *TD,
+ const TargetTransformInfo *TTI) {
bool Changed = false;
bool LocalChange = true;
while (LocalChange) {
@@ -302,7 +304,7 @@ static bool iterativelySimplifyCFG(Function &F, const DataLayout *TD) {
// Loop over all of the basic blocks and remove them if they are unneeded...
//
for (Function::iterator BBIt = F.begin(); BBIt != F.end(); ) {
- if (SimplifyCFG(BBIt++, TD)) {
+ if (SimplifyCFG(BBIt++, TD, TTI)) {
LocalChange = true;
++NumSimpl;
}
@@ -317,9 +319,11 @@ static bool iterativelySimplifyCFG(Function &F, const DataLayout *TD) {
//
bool CFGSimplifyPass::runOnFunction(Function &F) {
const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
+ const TargetTransformInfo *TTI =
+ getAnalysisIfAvailable<TargetTransformInfo>();
bool EverChanged = removeUnreachableBlocksFromFn(F);
EverChanged |= mergeEmptyReturnBlocks(F);
- EverChanged |= iterativelySimplifyCFG(F, TD);
+ EverChanged |= iterativelySimplifyCFG(F, TD, TTI);
// If neither pass changed anything, we're done.
if (!EverChanged) return false;
@@ -333,7 +337,7 @@ bool CFGSimplifyPass::runOnFunction(Function &F) {
return true;
do {
- EverChanged = iterativelySimplifyCFG(F, TD);
+ EverChanged = iterativelySimplifyCFG(F, TD, TTI);
EverChanged |= removeUnreachableBlocksFromFn(F);
} while (EverChanged);
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index f05a8ba..04ffc90 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -14,6 +14,7 @@
#define DEBUG_TYPE "simplifycfg"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Constants.h"
+#include "llvm/DataLayout.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalVariable.h"
#include "llvm/IRBuilder.h"
@@ -39,7 +40,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/NoFolder.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/DataLayout.h"
+#include "llvm/TargetTransformInfo.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include <algorithm>
#include <set>
@@ -82,6 +83,7 @@ namespace {
class SimplifyCFGOpt {
const DataLayout *const TD;
+ const TargetTransformInfo *const TTI;
Value *isValueEqualityComparison(TerminatorInst *TI);
BasicBlock *GetValueEqualityComparisonCases(TerminatorInst *TI,
@@ -101,7 +103,8 @@ class SimplifyCFGOpt {
bool SimplifyCondBranch(BranchInst *BI, IRBuilder <>&Builder);
public:
- explicit SimplifyCFGOpt(const DataLayout *td) : TD(td) {}
+ SimplifyCFGOpt(const DataLayout *td, const TargetTransformInfo *tti)
+ : TD(td), TTI(tti) {}
bool run(BasicBlock *BB);
};
}
@@ -3459,8 +3462,13 @@ static bool ShouldBuildLookupTable(SwitchInst *SI,
/// replace the switch with lookup tables.
static bool SwitchToLookupTable(SwitchInst *SI,
IRBuilder<> &Builder,
- const DataLayout* TD) {
+ const DataLayout* TD,
+ const TargetTransformInfo *TTI) {
assert(SI->getNumCases() > 1 && "Degenerate switch?");
+
+ if (TTI && !TTI->getScalarTargetTransformInfo()->shouldBuildLookupTables())
+ return false;
+
// FIXME: Handle unreachable cases.
// FIXME: If the switch is too sparse for a lookup table, perhaps we could
@@ -3619,7 +3627,7 @@ bool SimplifyCFGOpt::SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) {
if (ForwardSwitchConditionToPHI(SI))
return SimplifyCFG(BB) | true;
- if (SwitchToLookupTable(SI, Builder, TD))
+ if (SwitchToLookupTable(SI, Builder, TD, TTI))
return SimplifyCFG(BB) | true;
return false;
@@ -3916,6 +3924,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) {
/// eliminates unreachable basic blocks, and does other "peephole" optimization
/// of the CFG. It returns true if a modification was made.
///
-bool llvm::SimplifyCFG(BasicBlock *BB, const DataLayout *TD) {
- return SimplifyCFGOpt(TD).run(BB);
+bool llvm::SimplifyCFG(BasicBlock *BB, const DataLayout *TD,
+ const TargetTransformInfo *TTI) {
+ return SimplifyCFGOpt(TD, TTI).run(BB);
}
diff --git a/test/CodeGen/SPARC/load_to_switch.ll b/test/CodeGen/SPARC/load_to_switch.ll
deleted file mode 100644
index 8d62de5..0000000
--- a/test/CodeGen/SPARC/load_to_switch.ll
+++ /dev/null
@@ -1,84 +0,0 @@
-; RUN: llc -march=sparc < %s | FileCheck %s
-
-; Check that all the switches turned into lookup tables by SimplifyCFG are
-; turned back into switches for targets that don't like lookup tables.
-
-@.str = private unnamed_addr constant [4 x i8] c"foo\00", align 1
-@.str1 = private unnamed_addr constant [4 x i8] c"bar\00", align 1
-@.str2 = private unnamed_addr constant [4 x i8] c"baz\00", align 1
-@.str3 = private unnamed_addr constant [4 x i8] c"qux\00", align 1
-@.str4 = private unnamed_addr constant [6 x i8] c"error\00", align 1
-@switch.table = private unnamed_addr constant [7 x i32] [i32 55, i32 123, i32 0, i32 -1, i32 27, i32 62, i32 1]
-@switch.table1 = private unnamed_addr constant [4 x i8] c"*\09X\05"
-@switch.table2 = private unnamed_addr constant [4 x float] [float 0x40091EB860000000, float 0x3FF3BE76C0000000, float 0x4012449BA0000000, float 0x4001AE1480000000]
-@switch.table3 = private unnamed_addr constant [4 x i8*] [i8* getelementptr inbounds ([4 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8]* @.str1, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8]* @.str2, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8]* @.str3, i64 0, i64 0)]
-
-define i32 @f(i32 %c) {
-entry:
- %switch.tableidx = sub i32 %c, 42
- %0 = icmp ult i32 %switch.tableidx, 7
- br i1 %0, label %switch.lookup, label %return
-
-switch.lookup:
- %switch.gep = getelementptr inbounds [7 x i32]* @switch.table, i32 0, i32 %switch.tableidx
- %switch.load = load i32* %switch.gep
- ret i32 %switch.load
-
-return:
- ret i32 15
-
-; CHECK: f:
-; CHECK: %switch.lookup
-; CHECK-NOT: sethi %hi(.Lswitch.table)
-}
-
-declare void @dummy(i8 signext, float)
-
-define void @h(i32 %x) {
-entry:
- %switch.tableidx = sub i32 %x, 0
- %0 = icmp ult i32 %switch.tableidx, 4
- br i1 %0, label %switch.lookup, label %sw.epilog
-
-switch.lookup:
- %switch.gep = getelementptr inbounds [4 x i8]* @switch.table1, i32 0, i32 %switch.tableidx
- %switch.load = load i8* %switch.gep
- %switch.gep1 = getelementptr inbounds [4 x float]* @switch.table2, i32 0, i32 %switch.tableidx
- %switch.load2 = load float* %switch.gep1
- br label %sw.epilog
-
-sw.epilog:
- %a.0 = phi i8 [ %switch.load, %switch.lookup ], [ 7, %entry ]
- %b.0 = phi float [ %switch.load2, %switch.lookup ], [ 0x4023FAE140000000, %entry ]
- call void @dummy(i8 signext %a.0, float %b.0)
- ret void
-
-; CHECK: h:
-; CHECK: %switch.lookup
-; CHECK-NOT: sethi %hi(.Lswitch.table{{[0-9]}})
-; CHECK-NOT: sethi %hi(.Lswitch.table{{[0-9]}})
-}
-
-define i8* @foostring(i32 %x) {
-entry:
- %switch.tableidx = sub i32 %x, 0
- %0 = icmp ult i32 %switch.tableidx, 4
- br i1 %0, label %switch.lookup, label %return
-
-switch.lookup:
- %switch.gep = getelementptr inbounds [4 x i8*]* @switch.table3, i32 0, i32 %switch.tableidx
- %switch.load = load i8** %switch.gep
- ret i8* %switch.load
-
-return:
- ret i8* getelementptr inbounds ([6 x i8]* @.str4, i64 0, i64 0)
-
-; CHECK: foostring:
-; CHECK: %switch.lookup
-; CHECK-NOT: sethi %hi(.Lswitch.table3)
-}
-
-; CHECK-NOT: .Lswitch.table
-; CHECK-NOT: .Lswitch.table1
-; CHECK-NOT: .Lswitch.table2
-; CHECK-NOT: .Lswitch.table3
diff --git a/test/Transforms/SimplifyCFG/SPARC/lit.local.cfg b/test/Transforms/SimplifyCFG/SPARC/lit.local.cfg
new file mode 100644
index 0000000..786fee9
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/SPARC/lit.local.cfg
@@ -0,0 +1,6 @@
+config.suffixes = ['.ll', '.c', '.cpp']
+
+targets = set(config.root.targets_to_build.split())
+if not 'Sparc' in targets:
+ config.unsupported = True
+
diff --git a/test/Transforms/SimplifyCFG/SPARC/switch_to_lookup_table.ll b/test/Transforms/SimplifyCFG/SPARC/switch_to_lookup_table.ll
new file mode 100644
index 0000000..9d15685
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/SPARC/switch_to_lookup_table.ll
@@ -0,0 +1,32 @@
+; RUN: opt < %s -simplifycfg -S -mtriple=sparc-unknown-unknown | FileCheck %s
+
+; Check that switches are not turned into lookup tables, as this is not
+; considered profitable on the target.
+
+define i32 @f(i32 %c) nounwind uwtable readnone {
+entry:
+ switch i32 %c, label %sw.default [
+ i32 42, label %return
+ i32 43, label %sw.bb1
+ i32 44, label %sw.bb2
+ i32 45, label %sw.bb3
+ i32 46, label %sw.bb4
+ i32 47, label %sw.bb5
+ i32 48, label %sw.bb6
+ ]
+
+sw.bb1: br label %return
+sw.bb2: br label %return
+sw.bb3: br label %return
+sw.bb4: br label %return
+sw.bb5: br label %return
+sw.bb6: br label %return
+sw.default: br label %return
+return:
+ %retval.0 = phi i32 [ 15, %sw.default ], [ 1, %sw.bb6 ], [ 62, %sw.bb5 ], [ 27, %sw.bb4 ], [ -1, %sw.bb3 ], [ 0, %sw.bb2 ], [ 123, %sw.bb1 ], [ 55, %entry ]
+ ret i32 %retval.0
+
+; CHECK: @f
+; CHECK-NOT: getelementptr
+; CHECK: switch i32 %c
+}
generated by cgit v1.1 at 2025-02-14 18:44:02 +0000