[llvm] r250143 - [SCEV] Put some utilites in the ScalarEvolution class
Sanjoy Das via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 12 19:53:30 PDT 2015
Author: sanjoy
Date: Mon Oct 12 21:53:27 2015
New Revision: 250143
URL: http://llvm.org/viewvc/llvm-project?rev=250143&view=rev
Log:
[SCEV] Put some utilites in the ScalarEvolution class
In a later commit, `SplitBinaryAdd` will be used outside `IsConstDiff`,
so lift that out. And lift out `IsConstDiff` as
`computeConstantDifference` to keep things clean and to avoid playing
C++ access specifier games.
NFC.
Modified:
llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=250143&r1=250142&r2=250143&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Mon Oct 12 21:53:27 2015
@@ -581,6 +581,15 @@ namespace llvm {
bool isKnownPredicateViaSplitting(ICmpInst::Predicate Pred, const SCEV *LHS,
const SCEV *RHS);
+ /// Try to match the Expr as "(L + R)<Flags>".
+ bool splitBinaryAdd(const SCEV *Expr, const SCEV *&L, const SCEV *&R,
+ SCEV::NoWrapFlags &Flags);
+
+ /// Return true if More == (Less + C), where C is a constant. This is
+ /// intended to be used as a cheaper substitute for full SCEV subtraction.
+ bool computeConstantDifference(const SCEV *Less, const SCEV *More,
+ APInt &C);
+
/// Drop memoized information computed for S.
void forgetMemoizedResults(const SCEV *S);
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=250143&r1=250142&r2=250143&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Mon Oct 12 21:53:27 2015
@@ -7509,21 +7509,24 @@ bool ScalarEvolution::isImpliedCond(ICmp
return false;
}
-// Return true if More == (Less + C), where C is a constant.
-static bool IsConstDiff(ScalarEvolution &SE, const SCEV *Less, const SCEV *More,
- APInt &C) {
- // We avoid subtracting expressions here because this function is usually
- // fairly deep in the call stack (i.e. is called many times).
+bool ScalarEvolution::splitBinaryAdd(const SCEV *Expr,
+ const SCEV *&L, const SCEV *&R,
+ SCEV::NoWrapFlags &Flags) {
+ const auto *AE = dyn_cast<SCEVAddExpr>(Expr);
+ if (!AE || AE->getNumOperands() != 2)
+ return false;
- auto SplitBinaryAdd = [](const SCEV *Expr, const SCEV *&L, const SCEV *&R) {
- const auto *AE = dyn_cast<SCEVAddExpr>(Expr);
- if (!AE || AE->getNumOperands() != 2)
- return false;
+ L = AE->getOperand(0);
+ R = AE->getOperand(1);
+ Flags = AE->getNoWrapFlags();
+ return true;
+}
- L = AE->getOperand(0);
- R = AE->getOperand(1);
- return true;
- };
+bool ScalarEvolution::computeConstantDifference(const SCEV *Less,
+ const SCEV *More,
+ APInt &C) {
+ // We avoid subtracting expressions here because this function is usually
+ // fairly deep in the call stack (i.e. is called many times).
if (isa<SCEVAddRecExpr>(Less) && isa<SCEVAddRecExpr>(More)) {
const auto *LAR = cast<SCEVAddRecExpr>(Less);
@@ -7537,7 +7540,7 @@ static bool IsConstDiff(ScalarEvolution
if (!LAR->isAffine() || !MAR->isAffine())
return false;
- if (LAR->getStepRecurrence(SE) != MAR->getStepRecurrence(SE))
+ if (LAR->getStepRecurrence(*this) != MAR->getStepRecurrence(*this))
return false;
Less = LAR->getStart();
@@ -7554,14 +7557,15 @@ static bool IsConstDiff(ScalarEvolution
}
const SCEV *L, *R;
- if (SplitBinaryAdd(Less, L, R))
+ SCEV::NoWrapFlags Flags;
+ if (splitBinaryAdd(Less, L, R, Flags))
if (const auto *LC = dyn_cast<SCEVConstant>(L))
if (R == More) {
C = -(LC->getValue()->getValue());
return true;
}
- if (SplitBinaryAdd(More, L, R))
+ if (splitBinaryAdd(More, L, R, Flags))
if (const auto *LC = dyn_cast<SCEVConstant>(L))
if (R == Less) {
C = LC->getValue()->getValue();
@@ -7626,8 +7630,8 @@ bool ScalarEvolution::isImpliedCondOpera
// C)".
APInt LDiff, RDiff;
- if (!IsConstDiff(*this, FoundLHS, LHS, LDiff) ||
- !IsConstDiff(*this, FoundRHS, RHS, RDiff) ||
+ if (!computeConstantDifference(FoundLHS, LHS, LDiff) ||
+ !computeConstantDifference(FoundRHS, RHS, RDiff) ||
LDiff != RDiff)
return false;
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