[llvm-commits] [llvm] r112442 - in /llvm/trunk: include/llvm/Analysis/IVUsers.h lib/Analysis/IVUsers.cpp test/CodeGen/X86/lsr-reuse.ll
Dan Gohman
gohman at apple.com
Sun Aug 29 09:40:03 PDT 2010
Author: djg
Date: Sun Aug 29 11:40:03 2010
New Revision: 112442
URL: http://llvm.org/viewvc/llvm-project?rev=112442&view=rev
Log:
Make IVUsers iterative instead of recursive.
This has the side effect of reversing the order of most of
IVUser's results.
Modified:
llvm/trunk/include/llvm/Analysis/IVUsers.h
llvm/trunk/lib/Analysis/IVUsers.cpp
llvm/trunk/test/CodeGen/X86/lsr-reuse.ll
Modified: llvm/trunk/include/llvm/Analysis/IVUsers.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/IVUsers.h?rev=112442&r1=112441&r2=112442&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/IVUsers.h (original)
+++ llvm/trunk/include/llvm/Analysis/IVUsers.h Sun Aug 29 11:40:03 2010
@@ -27,6 +27,7 @@
class IVUsers;
class ScalarEvolution;
class SCEV;
+class SCEVAddRecExpr;
class IVUsers;
/// IVStrideUse - Keep track of one use of a strided induction variable.
@@ -122,7 +123,7 @@
LoopInfo *LI;
DominatorTree *DT;
ScalarEvolution *SE;
- SmallPtrSet<Instruction*,16> Processed;
+ SmallPtrSet<Instruction *, 16> Processed;
/// IVUses - A list of all tracked IV uses of induction variable expressions
/// we are interested in.
@@ -134,14 +135,16 @@
virtual void releaseMemory();
+ const SCEVAddRecExpr *findInterestingAddRec(const SCEV *S) const;
+ bool isInterestingUser(const Instruction *User) const;
+
public:
static char ID; // Pass ID, replacement for typeid
IVUsers();
- /// AddUsersIfInteresting - Inspect the specified Instruction. If it is a
- /// reducible SCEV, recursively add its users to the IVUsesByStride set and
- /// return true. Otherwise, return false.
- bool AddUsersIfInteresting(Instruction *I);
+ /// AddUsersIfInteresting - Inspect the def-use graph starting at the
+ /// specified Instruction and add IVUsers.
+ void AddUsersIfInteresting(Instruction *I);
IVStrideUse &AddUser(Instruction *User, Value *Operand);
Modified: llvm/trunk/lib/Analysis/IVUsers.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/IVUsers.cpp?rev=112442&r1=112441&r2=112442&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/IVUsers.cpp (original)
+++ llvm/trunk/lib/Analysis/IVUsers.cpp Sun Aug 29 11:40:03 2010
@@ -35,112 +35,123 @@
return new IVUsers();
}
-/// isInteresting - Test whether the given expression is "interesting" when
-/// used by the given expression, within the context of analyzing the
-/// given loop.
-static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L,
- ScalarEvolution *SE) {
+/// findInterestingAddRec - Test whether the given expression is interesting.
+/// Return the addrec with the current loop which makes it interesting, or
+/// null if it is not interesting.
+const SCEVAddRecExpr *IVUsers::findInterestingAddRec(const SCEV *S) const {
// An addrec is interesting if it's affine or if it has an interesting start.
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
// Keep things simple. Don't touch loop-variant strides.
if (AR->getLoop() == L)
- return AR->isAffine() || !L->contains(I);
- // Otherwise recurse to see if the start value is interesting, and that
- // the step value is not interesting, since we don't yet know how to
- // do effective SCEV expansions for addrecs with interesting steps.
- return isInteresting(AR->getStart(), I, L, SE) &&
- !isInteresting(AR->getStepRecurrence(*SE), I, L, SE);
+ return AR;
+ // We don't yet know how to do effective SCEV expansions for addrecs
+ // with interesting steps.
+ if (findInterestingAddRec(AR->getStepRecurrence(*SE)))
+ return 0;
+ // Otherwise recurse to see if the start value is interesting.
+ return findInterestingAddRec(AR->getStart());
}
// An add is interesting if exactly one of its operands is interesting.
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
- bool AnyInterestingYet = false;
for (SCEVAddExpr::op_iterator OI = Add->op_begin(), OE = Add->op_end();
OI != OE; ++OI)
- if (isInteresting(*OI, I, L, SE)) {
- if (AnyInterestingYet)
- return false;
- AnyInterestingYet = true;
- }
- return AnyInterestingYet;
+ if (const SCEVAddRecExpr *AR = findInterestingAddRec(*OI))
+ return AR;
+ return 0;
}
// Nothing else is interesting here.
- return false;
+ return 0;
}
-/// AddUsersIfInteresting - Inspect the specified instruction. If it is a
-/// reducible SCEV, recursively add its users to the IVUsesByStride set and
-/// return true. Otherwise, return false.
-bool IVUsers::AddUsersIfInteresting(Instruction *I) {
- if (!SE->isSCEVable(I->getType()))
- return false; // Void and FP expressions cannot be reduced.
+bool IVUsers::isInterestingUser(const Instruction *User) const {
+ // Void and FP expressions cannot be reduced.
+ if (!SE->isSCEVable(User->getType()))
+ return false;
// LSR is not APInt clean, do not touch integers bigger than 64-bits.
- if (SE->getTypeSizeInBits(I->getType()) > 64)
+ if (SE->getTypeSizeInBits(User->getType()) > 64)
return false;
- if (!Processed.insert(I))
- return true; // Instruction already handled.
+ // Don't descend into PHI nodes outside the current loop.
+ if (LI->getLoopFor(User->getParent()) != L &&
+ isa<PHINode>(User))
+ return false;
- // Get the symbolic expression for this instruction.
- const SCEV *ISE = SE->getSCEV(I);
+ // Otherwise, it may be interesting.
+ return true;
+}
- // If we've come to an uninteresting expression, stop the traversal and
- // call this a user.
- if (!isInteresting(ISE, I, L, SE))
- return false;
+/// AddUsersIfInteresting - Inspect the specified instruction. If it is a
+/// reducible SCEV, recursively add its users to the IVUsesByStride set and
+/// return true. Otherwise, return false.
+void IVUsers::AddUsersIfInteresting(Instruction *I) {
+ // Stop if we've seen this before.
+ if (!Processed.insert(I))
+ return;
- SmallPtrSet<Instruction *, 4> UniqueUsers;
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
- if (!UniqueUsers.insert(User))
- continue;
-
- // Do not infinitely recurse on PHI nodes.
- if (isa<PHINode>(User) && Processed.count(User))
- continue;
-
- // Descend recursively, but not into PHI nodes outside the current loop.
- // It's important to see the entire expression outside the loop to get
- // choices that depend on addressing mode use right, although we won't
- // consider references outside the loop in all cases.
- // If User is already in Processed, we don't want to recurse into it again,
- // but do want to record a second reference in the same instruction.
- bool AddUserToIVUsers = false;
- if (LI->getLoopFor(User->getParent()) != L) {
- if (isa<PHINode>(User) || Processed.count(User) ||
- !AddUsersIfInteresting(User)) {
- DEBUG(dbgs() << "FOUND USER in other loop: " << *User << '\n'
- << " OF SCEV: " << *ISE << '\n');
- AddUserToIVUsers = true;
+ // If this PHI node is not SCEVable, ignore it.
+ if (!SE->isSCEVable(I->getType()))
+ return;
+
+ // If this PHI node is not an addrec for this loop, ignore it.
+ const SCEVAddRecExpr *Expr = findInterestingAddRec(SE->getSCEV(I));
+ if (!Expr)
+ return;
+
+ // Walk the def-use graph.
+ SmallVector<std::pair<Instruction *, const SCEVAddRecExpr *>, 16> Worklist;
+ Worklist.push_back(std::make_pair(I, Expr));
+ do {
+ std::pair<Instruction *, const SCEVAddRecExpr *> P =
+ Worklist.pop_back_val();
+ Instruction *Op = P.first;
+ const SCEVAddRecExpr *OpAR = P.second;
+
+ // Visit Op's users.
+ SmallPtrSet<Instruction *, 8> VisitedUsers;
+ for (Value::use_iterator UI = Op->use_begin(), E = Op->use_end();
+ UI != E; ++UI) {
+ // Don't visit any individual user more than once.
+ Instruction *User = cast<Instruction>(*UI);
+ if (!VisitedUsers.insert(User))
+ continue;
+
+ // If it's an affine addrec (which we can pretty safely re-expand) inside
+ // the loop, or a potentially non-affine addrec outside the loop (which
+ // we can evaluate outside of the loop), follow it.
+ if (OpAR->isAffine() || !L->contains(User)) {
+ if (isInterestingUser(User)) {
+ const SCEV *UserExpr = SE->getSCEV(User);
+
+ if (const SCEVAddRecExpr *AR = findInterestingAddRec(UserExpr)) {
+ // Interesting. Keep searching.
+ if (Processed.insert(User))
+ Worklist.push_back(std::make_pair(User, AR));
+ continue;
+ }
+ }
}
- } else if (Processed.count(User) ||
- !AddUsersIfInteresting(User)) {
- DEBUG(dbgs() << "FOUND USER: " << *User << '\n'
- << " OF SCEV: " << *ISE << '\n');
- AddUserToIVUsers = true;
- }
- if (AddUserToIVUsers) {
- // Okay, we found a user that we cannot reduce.
- IVUses.push_back(new IVStrideUse(this, User, I));
- IVStrideUse &NewUse = IVUses.back();
- // Transform the expression into a normalized form.
- ISE = TransformForPostIncUse(NormalizeAutodetect,
- ISE, User, I,
- NewUse.PostIncLoops,
- *SE, *DT);
- DEBUG(dbgs() << " NORMALIZED TO: " << *ISE << '\n');
+ // Otherwise, this is the point where the def-use chain
+ // becomes uninteresting. Call it an IV User.
+ AddUser(User, Op);
}
- }
- return true;
+ } while (!Worklist.empty());
}
IVStrideUse &IVUsers::AddUser(Instruction *User, Value *Operand) {
IVUses.push_back(new IVStrideUse(this, User, Operand));
- return IVUses.back();
+ IVStrideUse &NewUse = IVUses.back();
+
+ // Auto-detect and remember post-inc loops for this expression.
+ const SCEV *S = SE->getSCEV(Operand);
+ (void)TransformForPostIncUse(NormalizeAutodetect,
+ S, User, Operand,
+ NewUse.PostIncLoops,
+ *SE, *DT);
+ return NewUse;
}
IVUsers::IVUsers()
@@ -165,7 +176,7 @@
// 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.
for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I)
- (void)AddUsersIfInteresting(I);
+ AddUsersIfInteresting(I);
return false;
}
Modified: llvm/trunk/test/CodeGen/X86/lsr-reuse.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/lsr-reuse.ll?rev=112442&r1=112441&r2=112442&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/lsr-reuse.ll (original)
+++ llvm/trunk/test/CodeGen/X86/lsr-reuse.ll Sun Aug 29 11:40:03 2010
@@ -452,9 +452,9 @@
; CHECK-NEXT: addss %xmm{{.*}}, %xmm{{.*}}
; CHECK-NEXT: mulss (%r{{[^,]*}}), %xmm{{.*}}
; CHECK-NEXT: movss %xmm{{.*}}, (%r{{[^,]*}})
-; CHECK-NEXT: addq $4, %r{{.*}}
; CHECK-NEXT: decq %r{{.*}}
; CHECK-NEXT: addq $4, %r{{.*}}
+; CHECK-NEXT: addq $4, %r{{.*}}
; CHECK-NEXT: movaps %xmm{{.*}}, %xmm{{.*}}
; CHECK-NEXT: BB10_2:
; CHECK-NEXT: testq %r{{.*}}, %r{{.*}}
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