[llvm-commits] [llvm] r55674 - in /llvm/trunk: lib/Transforms/Scalar/LoopStrengthReduce.cpp test/Transforms/LoopStrengthReduce/2008-09-02-IVType.ll
Devang Patel
dpatel at apple.com
Tue Sep 2 15:18:08 PDT 2008
Author: dpatel
Date: Tue Sep 2 17:18:08 2008
New Revision: 55674
URL: http://llvm.org/viewvc/llvm-project?rev=55674&view=rev
Log:
If all IV uses are extending integer IV then change the type of IV itself, if possible.
Added:
llvm/trunk/test/Transforms/LoopStrengthReduce/2008-09-02-IVType.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=55674&r1=55673&r2=55674&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Tue Sep 2 17:18:08 2008
@@ -46,6 +46,7 @@
STATISTIC(NumVariable, "Number of PHIs with variable strides");
STATISTIC(NumEliminated, "Number of strides eliminated");
STATISTIC(NumShadow, "Number of Shadow IVs optimized");
+STATISTIC(NumIVType, "Number of IV types optimized");
namespace {
@@ -184,6 +185,10 @@
/// inside the loop then try to eliminate the cast opeation.
void OptimizeShadowIV(Loop *L);
+ /// OptimizeIVType - If IV is always sext'ed or zext'ed then
+ /// change the type of IV, if possible.
+ void OptimizeIVType(Loop *L);
+
bool FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse,
const SCEVHandle *&CondStride);
bool RequiresTypeConversion(const Type *Ty, const Type *NewTy);
@@ -1808,6 +1813,200 @@
}
}
+/// suitableExtInstruction - Helper function used by OptimizeIVType.
+/// If I is a suitable SEXT or ZEXT instruction then return type
+/// to which I is extended to. Otherwise return NULL.
+const Type *suitableExtInstruction(Instruction *I, bool isSigned,
+ const Type *ExtType) {
+
+ const Type *DestType = NULL;
+ if (ZExtInst *ZI = dyn_cast<ZExtInst>(I))
+ DestType = ZI->getDestTy();
+ else if (SExtInst *SI = dyn_cast<SExtInst>(I)) {
+ // If the inital value is signed then this is not suitable for
+ // OptimizeIVType transformation.
+ if (isSigned)
+ return NULL;
+ DestType = SI->getDestTy();
+ }
+
+ if (!DestType) return NULL;
+
+ if (!ExtType)
+ return DestType;
+
+ // If another use of IV extended to some other type then the IV is not
+ // suitable for OptimizeIVType transformation.
+ if (ExtType != DestType)
+ return NULL;
+
+ return DestType;
+}
+
+/// suitableIVIncr - Helper function used by OptimizeIVType. If I is
+/// a suitable binary operator whose all uses are either SEXT or ZEXT
+/// then return the type to which all uses are extended to. Otherwise
+/// return NULL.
+const Type *suitableIVIncr(Instruction *I,
+ Instruction *PHI, bool isSigned,
+ const Type *ExtType) {
+
+ BinaryOperator *Incr = dyn_cast<BinaryOperator>(I);
+ if (!Incr) return NULL;
+
+ if (Incr->getOpcode() != Instruction::Add)
+ return NULL;
+
+ ConstantInt *C = NULL;
+ if (Incr->getOperand(0) == PHI)
+ C = dyn_cast<ConstantInt>(Incr->getOperand(1));
+ else if (Incr->getOperand(1) == PHI)
+ C = dyn_cast<ConstantInt>(Incr->getOperand(0));
+
+ if (!C) return NULL;
+
+ const Type *RExtType = NULL;
+ for (Value::use_iterator IncUI = Incr->use_begin(),
+ IncUE = Incr->use_end(); IncUI != IncUE; ++IncUI) {
+
+ Instruction *U2 = dyn_cast<Instruction>(*IncUI);
+ if (U2 == PHI)
+ continue;
+ const Type *DestType = suitableExtInstruction(U2, isSigned, ExtType);
+ if (!DestType)
+ return NULL;
+
+ if (!RExtType)
+ RExtType = DestType;
+
+ if (DestType != RExtType)
+ return NULL;
+ }
+
+ return RExtType;
+
+}
+
+/// getNewPHIIncrement - Create a new increment instruction for newPHI
+/// using type Ty based on increment instruction Incr.
+/// Helper function used by OptimizeIVType.
+BinaryOperator *getNewPHIIncrement(BinaryOperator *Incr, PHINode *PHI,
+ PHINode *NewPHI, const Type *Ty) {
+ ConstantInt *C = NULL;
+ if (Incr->getOperand(0) == PHI)
+ C = dyn_cast<ConstantInt>(Incr->getOperand(1));
+ else if (Incr->getOperand(1) == PHI)
+ C = dyn_cast<ConstantInt>(Incr->getOperand(0));
+
+ assert (C && "Unexpected Incr operand!");
+ return BinaryOperator::Create(Incr->getOpcode(), NewPHI,
+ ConstantInt::get(Ty, C->getZExtValue()),
+ "IV.next", Incr);
+}
+
+/// OptimizeIVType - If IV is always sext'ed or zext'ed then
+/// change the type of IV, if possible.
+void LoopStrengthReduce::OptimizeIVType(Loop *L) {
+
+ BasicBlock *LPH = L->getLoopPreheader();
+ SmallVector<PHINode *, 4> PHIs;
+ for (BasicBlock::iterator BI = L->getHeader()->begin(),
+ BE = L->getHeader()->end(); BI != BE; ++BI) {
+ if (PHINode *PHI = dyn_cast<PHINode>(BI))
+ PHIs.push_back(PHI);
+ else
+ break;
+ }
+
+ while(!PHIs.empty()) {
+ PHINode *PHI = PHIs.back(); PHIs.pop_back();
+ if (PHI->getNumIncomingValues() != 2) continue;
+
+ unsigned Entry = 0, Latch = 1;
+ if (PHI->getIncomingBlock(0) != LPH) {
+ Entry = 1;
+ Latch = 0;
+ }
+
+ ConstantInt *CInit = dyn_cast<ConstantInt>(PHI->getIncomingValue(Entry));
+ if (!CInit) return;
+
+ bool signedInit = CInit->getValue().isNegative();
+
+ bool TransformPhi = true;
+ const Type *ExtType = NULL;
+ BinaryOperator *Incr = NULL;
+ SmallVector<Instruction *, 4> PHIUses;
+
+ // Collect all IV uses.
+ for (Value::use_iterator UI = PHI->use_begin(),
+ UE = PHI->use_end(); UI != UE; ++UI) {
+ Instruction *Use = dyn_cast<Instruction>(*UI);
+ if (!Use) {
+ TransformPhi = false;
+ break;
+ }
+
+ ExtType = suitableIVIncr(Use, PHI, signedInit, ExtType);
+ if (ExtType) {
+ Incr = cast<BinaryOperator>(Use);
+ continue;
+ }
+ ExtType = suitableExtInstruction(Use, signedInit, ExtType);
+ if (ExtType) {
+ PHIUses.push_back(Use);
+ continue;
+ }
+
+ TransformPhi = false;
+ break;
+ }
+
+ if (!TransformPhi || Incr == false || PHIUses.empty())
+ continue;
+
+ // Apply transformation. Extend IV type and eliminate SEXT or ZEXT
+ // instructions.
+ NumIVType++;
+
+ PHINode *NewPH = PHINode::Create(ExtType, "IV", PHI);
+ ConstantInt *NewCInit = ConstantInt::get(ExtType, CInit->getZExtValue());
+ BinaryOperator *NewIncr = getNewPHIIncrement(Incr, PHI, NewPH, ExtType);
+
+ NewPH->addIncoming(NewCInit, PHI->getIncomingBlock(Entry));
+ NewPH->addIncoming(NewIncr, PHI->getIncomingBlock(Latch));
+
+ // Replace all SEXT or ZEXT uses with new IV directly.
+ while (!PHIUses.empty()) {
+ Instruction *Use = PHIUses.back(); PHIUses.pop_back();
+ SE->deleteValueFromRecords(Use);
+ Use->replaceAllUsesWith(NewPH);
+ Use->eraseFromParent();
+ }
+
+ // Replace all uses of IV increment with new increment.
+ SmallVector<Instruction *, 2> IncrUses;
+ for (Value::use_iterator UI2 = Incr->use_begin(),
+ UE2 = Incr->use_end(); UI2 != UE2; ++UI2)
+ IncrUses.push_back(cast<Instruction>(*UI2));
+
+ while (!IncrUses.empty()) {
+ Instruction *Use = IncrUses.back(); IncrUses.pop_back();
+ if (Use == PHI) continue;
+ SE->deleteValueFromRecords(Use);
+ Use->replaceAllUsesWith(NewIncr);
+ Use->eraseFromParent();
+ }
+
+ // Remove old PHI and increment instruction.
+ SE->deleteValueFromRecords(PHI);
+ PHI->removeIncomingValue(Entry);
+ PHI->removeIncomingValue(Latch);
+ SE->deleteValueFromRecords(Incr);
+ Incr->eraseFromParent();
+ }
+}
+
// OptimizeIndvars - Now that IVUsesByStride is set up with all of the indvar
// uses in the loop, look to see if we can eliminate some, in favor of using
// common indvars for the different uses.
@@ -1877,6 +2076,8 @@
UIntPtrTy = TD->getIntPtrType();
Changed = false;
+ OptimizeIVType(L);
+
// Find all uses of induction variables in this loop, and catagorize
// them by stride. Start by finding all of the PHI nodes in the header for
// this loop. If they are induction variables, inspect their uses.
Added: llvm/trunk/test/Transforms/LoopStrengthReduce/2008-09-02-IVType.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopStrengthReduce/2008-09-02-IVType.ll?rev=55674&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopStrengthReduce/2008-09-02-IVType.ll (added)
+++ llvm/trunk/test/Transforms/LoopStrengthReduce/2008-09-02-IVType.ll Tue Sep 2 17:18:08 2008
@@ -0,0 +1,57 @@
+; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis | grep sext | count 1
+; ModuleID = '<stdin>'
+ %struct.App1Marker = type <{ i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 }>
+ %struct.ComponentInstanceRecord = type <{ [1 x i32] }>
+ %struct.DCPredictors = type { [5 x i16] }
+ %struct.DecodeTable = type { i16, i16, i16, i16, i8**, i8** }
+ %struct.ICMDataProcRecord = type <{ i16 (i8**, i32, i32)*, i32 }>
+ %struct.JPEGBitStream = type { i8*, i32, i32, i32, i32, i32, %struct.App1Marker*, i8*, i32, i16, i16, i32 }
+ %struct.JPEGGlobals = type { [2048 x i8], %struct.JPEGBitStream, i8*, i32, i32, %struct.ComponentInstanceRecord*, %struct.ComponentInstanceRecord*, i32, %struct.OpaqueQTMLMutex*, %struct.Rect, i32, i32, %struct.SharedGlobals, %struct.DCPredictors, i8, i8, void (i8*, i16**, i32, %struct.YUVGeneralParams*)*, %struct.YUVGeneralParams, i16, i16, i32, [5 x i16*], [5 x %struct.DecodeTable*], [5 x %struct.DecodeTable*], [5 x i8], [5 x i8], [4 x [65 x i16]], [4 x %struct.DecodeTable], [4 x %struct.DecodeTable], [4 x i8*], [4 x i8*], i16, i16, i32, i8**, i8**, i8**, i8**, i8**, i8**, i8**, i8**, i8**, i8**, [18 x i8], [18 x i8], [18 x i8], [18 x i8], i32, i32, i8**, i8**, i8, i8, i8, i8, i16, i16, %struct.App1Marker*, i8, i8, i8, i8, i32**, i8*, i16*, i8*, i16*, i8, [3 x i8], i32, [3 x i32], [3 x i32], [3 x i32], [3 x i32], [3 x i32], [3 x i16*], [3 x i16*], [3 x i8**], [3 x %struct.DecodeTable*], [3 x %struct.DecodeTable*], [3 x i32], i32, [3 x i16*], i32, i32, i32, [3 x i32], i8,!
i8, i8, i8, %struct.ICMDataProcRecord*, i32, i32, i8**, i8**, i8**, i8**, i32, i32, i8*, i32, i32, i16*, i16*, i8*, i32, i32, i32, i32, i32, i32, i32, [16 x <2 x i64>], [1280 x i8], i8 }
+ %struct.OpaqueQTMLMutex = type opaque
+ %struct.Rect = type { i16, i16, i16, i16 }
+ %struct.SharedDGlobals = type { %struct.DecodeTable, %struct.DecodeTable, %struct.DecodeTable, %struct.DecodeTable }
+ %struct.SharedEGlobals = type { i8**, i8**, i8**, i8** }
+ %struct.SharedGlobals = type { %struct.SharedEGlobals*, %struct.SharedDGlobals* }
+ %struct.YUVGeneralParams = type { i16*, i8*, i8*, i8*, i8*, i8*, void (i8*, i16**, i32, %struct.YUVGeneralParams*)*, i16, i16, i16, [6 x i8], void (i8*, i16**, i32, %struct.YUVGeneralParams*)*, i16, i16 }
+ at llvm.used = appending global [1 x i8*] [ i8* bitcast (i16 (%struct.JPEGGlobals*)* @ExtractBufferedBlocksIgnored to i8*) ], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]
+
+define i16 @ExtractBufferedBlocksIgnored(%struct.JPEGGlobals* %globp) signext nounwind {
+entry:
+ %tmp4311 = getelementptr %struct.JPEGGlobals* %globp, i32 0, i32 70 ; <i32*> [#uses=1]
+ %tmp4412 = load i32* %tmp4311, align 16 ; <i32> [#uses=2]
+ %tmp4613 = icmp sgt i32 %tmp4412, 0 ; <i1> [#uses=1]
+ br i1 %tmp4613, label %bb, label %bb49
+
+bb: ; preds = %bb28, %entry
+ %component.09 = phi i16 [ 0, %entry ], [ %tmp37, %bb28 ] ; <i16> [#uses=2]
+ %tmp12 = sext i16 %component.09 to i32 ; <i32> [#uses=2]
+ %tmp6 = getelementptr %struct.JPEGGlobals* %globp, i32 0, i32 77, i32 %tmp12 ; <i16**> [#uses=2]
+ %tmp7 = load i16** %tmp6, align 4 ; <i16*> [#uses=2]
+ %tmp235 = getelementptr %struct.JPEGGlobals* %globp, i32 0, i32 71, i32 %tmp12 ; <i32*> [#uses=1]
+ %tmp246 = load i32* %tmp235, align 4 ; <i32> [#uses=2]
+ %tmp267 = icmp sgt i32 %tmp246, 0 ; <i1> [#uses=1]
+ br i1 %tmp267, label %bb8, label %bb28
+
+bb8: ; preds = %bb8, %bb
+ %indvar = phi i32 [ 0, %bb ], [ %indvar.next2, %bb8 ] ; <i32> [#uses=3]
+ %theDCTBufferIter.01.rec = shl i32 %indvar, 6 ; <i32> [#uses=1]
+ %tmp10.rec = add i32 %theDCTBufferIter.01.rec, 64 ; <i32> [#uses=1]
+ %tmp10 = getelementptr i16* %tmp7, i32 %tmp10.rec ; <i16*> [#uses=1]
+ %i.02 = trunc i32 %indvar to i16 ; <i16> [#uses=1]
+ %tmp13 = add i16 %i.02, 1 ; <i16> [#uses=1]
+ %phitmp = sext i16 %tmp13 to i32 ; <i32> [#uses=1]
+ %tmp26 = icmp slt i32 %phitmp, %tmp246 ; <i1> [#uses=1]
+ %indvar.next2 = add i32 %indvar, 1 ; <i32> [#uses=1]
+ br i1 %tmp26, label %bb8, label %bb28
+
+bb28: ; preds = %bb8, %bb
+ %theDCTBufferIter.0.lcssa = phi i16* [ %tmp7, %bb ], [ %tmp10, %bb8 ] ; <i16*> [#uses=1]
+ store i16* %theDCTBufferIter.0.lcssa, i16** %tmp6, align 4
+ %tmp37 = add i16 %component.09, 1 ; <i16> [#uses=2]
+ %phitmp15 = sext i16 %tmp37 to i32 ; <i32> [#uses=1]
+ %tmp46 = icmp slt i32 %phitmp15, %tmp4412 ; <i1> [#uses=1]
+ br i1 %tmp46, label %bb, label %bb49
+
+bb49: ; preds = %bb28, %entry
+ ret i16 0
+}
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