[llvm-commits] [llvm] r112267 - /llvm/trunk/lib/Analysis/ScalarEvolution.cpp
Dan Gohman
gohman at apple.com
Fri Aug 27 08:26:01 PDT 2010
Author: djg
Date: Fri Aug 27 10:26:01 2010
New Revision: 112267
URL: http://llvm.org/viewvc/llvm-project?rev=112267&view=rev
Log:
Optimize SCEVComplexityCompare. Use a 3-way return instead of a 2-way
return to avoid needing two calls to test for equivalence, and sort
addrecs by their degree before examining their operands.
Modified:
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=112267&r1=112266&r2=112267&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Fri Aug 27 10:26:01 2010
@@ -523,24 +523,34 @@
public:
explicit SCEVComplexityCompare(const LoopInfo *li) : LI(li) {}
+ // Return true or false if LHS is less than, or at least RHS, respectively.
bool operator()(const SCEV *LHS, const SCEV *RHS) const {
+ return compare(LHS, RHS) < 0;
+ }
+
+ // Return negative, zero, or positive, if LHS is less than, equal to, or
+ // greater than RHS, respectively. A three-way result allows recursive
+ // comparisons to be more efficient.
+ int compare(const SCEV *LHS, const SCEV *RHS) const {
// Fast-path: SCEVs are uniqued so we can do a quick equality check.
if (LHS == RHS)
- return false;
+ return 0;
// Primarily, sort the SCEVs by their getSCEVType().
unsigned LType = LHS->getSCEVType(), RType = RHS->getSCEVType();
if (LType != RType)
- return LType < RType;
+ return (int)LType - (int)RType;
// Aside from the getSCEVType() ordering, the particular ordering
// isn't very important except that it's beneficial to be consistent,
// so that (a + b) and (b + a) don't end up as different expressions.
-
- // Sort SCEVUnknown values with some loose heuristics. TODO: This is
- // not as complete as it could be.
- if (const SCEVUnknown *LU = dyn_cast<SCEVUnknown>(LHS)) {
+ switch (LType) {
+ case scUnknown: {
+ const SCEVUnknown *LU = cast<SCEVUnknown>(LHS);
const SCEVUnknown *RU = cast<SCEVUnknown>(RHS);
+
+ // Sort SCEVUnknown values with some loose heuristics. TODO: This is
+ // not as complete as it could be.
const Value *LV = LU->getValue(), *RV = RU->getValue();
// Order pointer values after integer values. This helps SCEVExpander
@@ -548,22 +558,23 @@
bool LIsPointer = LV->getType()->isPointerTy(),
RIsPointer = RV->getType()->isPointerTy();
if (LIsPointer != RIsPointer)
- return RIsPointer;
+ return (int)LIsPointer - (int)RIsPointer;
// Compare getValueID values.
unsigned LID = LV->getValueID(),
RID = RV->getValueID();
if (LID != RID)
- return LID < RID;
+ return (int)LID - (int)RID;
// Sort arguments by their position.
if (const Argument *LA = dyn_cast<Argument>(LV)) {
const Argument *RA = cast<Argument>(RV);
- return LA->getArgNo() < RA->getArgNo();
+ unsigned LArgNo = LA->getArgNo(), RArgNo = RA->getArgNo();
+ return (int)LArgNo - (int)RArgNo;
}
- // For instructions, compare their loop depth, and their opcode.
- // This is pretty loose.
+ // For instructions, compare their loop depth, and their operand
+ // count. This is pretty loose.
if (const Instruction *LInst = dyn_cast<Instruction>(LV)) {
const Instruction *RInst = cast<Instruction>(RV);
@@ -574,82 +585,105 @@
unsigned LDepth = LI->getLoopDepth(LParent),
RDepth = LI->getLoopDepth(RParent);
if (LDepth != RDepth)
- return LDepth < RDepth;
+ return (int)LDepth - (int)RDepth;
}
// Compare the number of operands.
unsigned LNumOps = LInst->getNumOperands(),
RNumOps = RInst->getNumOperands();
- if (LNumOps != RNumOps)
- return LNumOps < RNumOps;
+ return (int)LNumOps - (int)RNumOps;
}
- return false;
+ return 0;
}
- // Compare constant values.
- if (const SCEVConstant *LC = dyn_cast<SCEVConstant>(LHS)) {
+ case scConstant: {
+ const SCEVConstant *LC = cast<SCEVConstant>(LHS);
const SCEVConstant *RC = cast<SCEVConstant>(RHS);
+
+ // Compare constant values.
const APInt &LA = LC->getValue()->getValue();
const APInt &RA = RC->getValue()->getValue();
unsigned LBitWidth = LA.getBitWidth(), RBitWidth = RA.getBitWidth();
if (LBitWidth != RBitWidth)
- return LBitWidth < RBitWidth;
- return LA.ult(RA);
+ return (int)LBitWidth - (int)RBitWidth;
+ return LA.ult(RA) ? -1 : 1;
}
- // Compare addrec loop depths.
- if (const SCEVAddRecExpr *LA = dyn_cast<SCEVAddRecExpr>(LHS)) {
+ case scAddRecExpr: {
+ const SCEVAddRecExpr *LA = cast<SCEVAddRecExpr>(LHS);
const SCEVAddRecExpr *RA = cast<SCEVAddRecExpr>(RHS);
+
+ // Compare addrec loop depths.
const Loop *LLoop = LA->getLoop(), *RLoop = RA->getLoop();
if (LLoop != RLoop) {
unsigned LDepth = LLoop->getLoopDepth(),
RDepth = RLoop->getLoopDepth();
if (LDepth != RDepth)
- return LDepth < RDepth;
+ return (int)LDepth - (int)RDepth;
}
+
+ // Addrec complexity grows with operand count.
+ unsigned LNumOps = LA->getNumOperands(), RNumOps = RA->getNumOperands();
+ if (LNumOps != RNumOps)
+ return (int)LNumOps - (int)RNumOps;
+
+ // Lexicographically compare.
+ for (unsigned i = 0; i != LNumOps; ++i) {
+ long X = compare(LA->getOperand(i), RA->getOperand(i));
+ if (X != 0)
+ return X;
+ }
+
+ return 0;
}
- // Lexicographically compare n-ary expressions.
- if (const SCEVNAryExpr *LC = dyn_cast<SCEVNAryExpr>(LHS)) {
+ case scAddExpr:
+ case scMulExpr:
+ case scSMaxExpr:
+ case scUMaxExpr: {
+ const SCEVNAryExpr *LC = cast<SCEVNAryExpr>(LHS);
const SCEVNAryExpr *RC = cast<SCEVNAryExpr>(RHS);
+
+ // Lexicographically compare n-ary expressions.
unsigned LNumOps = LC->getNumOperands(), RNumOps = RC->getNumOperands();
for (unsigned i = 0; i != LNumOps; ++i) {
if (i >= RNumOps)
- return false;
- const SCEV *LOp = LC->getOperand(i), *ROp = RC->getOperand(i);
- if (operator()(LOp, ROp))
- return true;
- if (operator()(ROp, LOp))
- return false;
+ return 1;
+ long X = compare(LC->getOperand(i), RC->getOperand(i));
+ if (X != 0)
+ return X;
}
- return LNumOps < RNumOps;
+ return (int)LNumOps - (int)RNumOps;
}
- // Lexicographically compare udiv expressions.
- if (const SCEVUDivExpr *LC = dyn_cast<SCEVUDivExpr>(LHS)) {
+ case scUDivExpr: {
+ const SCEVUDivExpr *LC = cast<SCEVUDivExpr>(LHS);
const SCEVUDivExpr *RC = cast<SCEVUDivExpr>(RHS);
- const SCEV *LL = LC->getLHS(), *LR = LC->getRHS(),
- *RL = RC->getLHS(), *RR = RC->getRHS();
- if (operator()(LL, RL))
- return true;
- if (operator()(RL, LL))
- return false;
- if (operator()(LR, RR))
- return true;
- if (operator()(RR, LR))
- return false;
- return false;
+
+ // Lexicographically compare udiv expressions.
+ long X = compare(LC->getLHS(), RC->getLHS());
+ if (X != 0)
+ return X;
+ return compare(LC->getRHS(), RC->getRHS());
}
- // Compare cast expressions by operand.
- if (const SCEVCastExpr *LC = dyn_cast<SCEVCastExpr>(LHS)) {
+ case scTruncate:
+ case scZeroExtend:
+ case scSignExtend: {
+ const SCEVCastExpr *LC = cast<SCEVCastExpr>(LHS);
const SCEVCastExpr *RC = cast<SCEVCastExpr>(RHS);
- return operator()(LC->getOperand(), RC->getOperand());
+
+ // Compare cast expressions by operand.
+ return compare(LC->getOperand(), RC->getOperand());
+ }
+
+ default:
+ break;
}
llvm_unreachable("Unknown SCEV kind!");
- return false;
+ return 0;
}
};
}
More information about the llvm-commits
mailing list