Changes in directory llvm/lib/Analysis:
ScalarEvolution.cpp updated: 1.72 -> 1.73
---
Log message:
Fix a bug in GetConstantFactor for affine expressions, in which the existing
code was wrong for things like 3+4*i.
---
Diffs of the changes: (+9 -5)
ScalarEvolution.cpp | 14 +++++++++-----
1 files changed, 9 insertions(+), 5 deletions(-)
Index: llvm/lib/Analysis/ScalarEvolution.cpp
diff -u llvm/lib/Analysis/ScalarEvolution.cpp:1.72
llvm/lib/Analysis/ScalarEvolution.cpp:1.73
--- llvm/lib/Analysis/ScalarEvolution.cpp:1.72 Tue Dec 12 17:36:14 2006
+++ llvm/lib/Analysis/ScalarEvolution.cpp Mon Dec 18 19:16:02 2006
@@ -74,6 +74,7 @@
#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Streams.h"
#include "llvm/ADT/Statistic.h"
#include <ostream>
@@ -1372,11 +1373,14 @@
}
if (SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
- // FIXME: Generalize.
- if (A->getNumOperands() == 2)
- return std::min(GetConstantFactor(A->getOperand(0)),
- GetConstantFactor(A->getOperand(1)));
- // ?
+ // For now, we just handle linear expressions.
+ if (A->getNumOperands() == 2) {
+ // We want the GCD between the start and the stride value.
+ uint64_t Start = GetConstantFactor(A->getOperand(0));
+ if (Start == 1) return 1;
+ uint64_t Stride = GetConstantFactor(A->getOperand(1));
+ return GreatestCommonDivisor64(Start, Stride);
+ }
}
// SCEVSDivExpr, SCEVUnknown.
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