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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2012-09-27 18:29:58 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2012-09-27 18:29:58 +0000 |
| commit | 465251a7ce52161adbcb6e80cb84f135dd440de9 (patch) | |
| tree | b233658fd9261a438afb9f88adb2b8c06b61af79 /lib/Transforms/Utils/SimplifyCFG.cpp | |
| parent | 593c0b08e651a34266825e41659004e7f932ffb9 (diff) | |
Fix a integer overflow in SimplifyCFG's look up table formation logic.
If the width is very large it gets truncated from uint64_t to uint32_t when
passed to TD->fitsInLegalInteger. The truncated value can fit in a register.
This manifested in massive memory usage or crashes (PR13946).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164784 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 299c0596da..065325b7c2 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -3414,6 +3414,10 @@ bool SwitchLookupTable::WouldFitInRegister(const TargetData *TD, return false; // FIXME: If the type is wider than it needs to be, e.g. i8 but all values // are <= 15, we could try to narrow the type. + + // Avoid overflow, fitsInLegalInteger uses unsigned int for the width. + if (TableSize >= UINT_MAX/IT->getBitWidth()) + return false; return TD->fitsInLegalInteger(TableSize * IT->getBitWidth()); } |