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A couple minor corrections to r139276.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139277 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman
2011-09-08 02:37:07 +00:00
parent 81ac8ddc67
commit 184166da61
1 changed files with 13 additions and 13 deletions
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26
lib/Analysis/BasicAliasAnalysis.cpp
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@ -977,20 +977,20 @@ BasicAliasAnalysis::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
// Try to distinguish something like &A[i][1] against &A[42][0]. // Try to distinguish something like &A[i][1] against &A[42][0].
// Grab the least significant bit set in any of the scales. // Grab the least significant bit set in any of the scales.
uint64_t Modulo = 0; if (!GEP1VariableIndices.empty()) {
for (unsigned i = 0, e = GEP1VariableIndices.size(); uint64_t Modulo = 0;
i != e; ++i) for (unsigned i = 0, e = GEP1VariableIndices.size(); i != e; ++i)
Modulo |= (uint64_t)GEP1VariableIndices[0].Scale; Modulo |= (uint64_t)GEP1VariableIndices[i].Scale;
Modulo = Modulo ^ (Modulo & (Modulo - 1)); Modulo = Modulo ^ (Modulo & (Modulo - 1));
// We can compute the difference between the two addresses
// mod Modulo. Check whether that difference guarantees that the
// two locations do not alias.
uint64_t ModOffset = (uint64_t)GEP1BaseOffset & (Modulo - 1);
if (V1Size != UnknownSize && V2Size != UnknownSize &&
ModOffset >= V2Size && V1Size <= Modulo - ModOffset)
return NoAlias;
// We can compute the difference between the two addresses
// mod Modulo. Check whether that difference guarantees that the
// two locations do not alias.
uint64_t ModOffset = (uint64_t)GEP1BaseOffset & (Modulo - 1);
if (V1Size != UnknownSize && V2Size != UnknownSize &&
ModOffset >= V2Size && V1Size <= Modulo - ModOffset)
return NoAlias;
}
// Statically, we can see that the base objects are the same, but the // Statically, we can see that the base objects are the same, but the
// pointers have dynamic offsets which we can't resolve. And none of our // pointers have dynamic offsets which we can't resolve. And none of our