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author | Shuxin Yang <shuxin.llvm@gmail.com> | 2013-10-23 17:28:19 +0000 |
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committer | Shuxin Yang <shuxin.llvm@gmail.com> | 2013-10-23 17:28:19 +0000 |
commit | 8e3851a6eb9fe5fc30094c3a00d2b89c7cd68cbd (patch) | |
tree | aa761eb31c1f7c14a3c9e313f4a1d29ea06e066b /lib/Analysis | |
parent | f39fe46062d2093fc3d7c092bc8c4561b744164c (diff) | |
download | llvm-8e3851a6eb9fe5fc30094c3a00d2b89c7cd68cbd.tar.gz llvm-8e3851a6eb9fe5fc30094c3a00d2b89c7cd68cbd.tar.bz2 llvm-8e3851a6eb9fe5fc30094c3a00d2b89c7cd68cbd.tar.xz |
Use address-taken to disambiguate global variable and indirect memops.
Major steps include:
1). introduces a not-addr-taken bit-field in GlobalVariable
2). GlobalOpt pass sets "not-address-taken" if it proves a global varirable
dosen't have its address taken.
3). AA use this info for disambiguation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193251 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis')
-rw-r--r-- | lib/Analysis/BasicAliasAnalysis.cpp | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp index bf929690ae..4e423a787c 100644 --- a/lib/Analysis/BasicAliasAnalysis.cpp +++ b/lib/Analysis/BasicAliasAnalysis.cpp @@ -1238,6 +1238,17 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, uint64_t V1Size, return NoAlias; if (isEscapeSource(O2) && isNonEscapingLocalObject(O1)) return NoAlias; + + // If one object is a global variable without address taken, the other one + // is a different object, they will not alias because the global variable + // in question cannot be indirectly accessed. + if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(O1)) + if (!GV->AddressMaybeTaken()) + return NoAlias; + + if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(O2)) + if (!GV->AddressMaybeTaken()) + return NoAlias; } // If the size of one access is larger than the entire object on the other |