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Address Duncan's comments on r164682: 

- Finish assert messages with exclamation mark
- Move overflow checking into ShouldBuildLookupTable.

llvm-svn: 164692
This commit is contained in:
Hans Wennborg 2012-09-26 11:07:37 +00:00
parent 208124f5a2
commit f2e2c108dd
1 changed files with 4 additions and 6 deletions
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10
llvm/lib/Transforms/Utils/SimplifyCFG.cpp
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@ -3302,8 +3302,8 @@ SwitchLookupTable::SwitchLookupTable(Module &M,
const SmallVector<std::pair<ConstantInt*, Constant*>, 4>& Values,
Constant *DefaultValue,
const TargetData *TD) {
assert(Values.size() && "Can't build lookup table without values.");
assert(TableSize >= Values.size() && "Can't fit values in table.");
assert(Values.size() && "Can't build lookup table without values!");
assert(TableSize >= Values.size() && "Can't fit values in table!");
// If all values in the table are equal, this is that value.
SingleValue = Values.begin()->second;
@ -3431,6 +3431,8 @@ static bool ShouldBuildLookupTable(SwitchInst *SI,
// The table density should be at least 40%. This is the same criterion as for
// jump tables, see SelectionDAGBuilder::handleJTSwitchCase.
// FIXME: Find the best cut-off.
if (SI->getNumCases() > TableSize || TableSize >= UINT64_MAX / 10)
return false; // TableSize overflowed, or mul below might overflow.
if (SI->getNumCases() * 10 >= TableSize * 4)
return true;
@ -3513,10 +3515,6 @@ static bool SwitchToLookupTable(SwitchInst *SI,
}
APInt RangeSpread = MaxCaseVal->getValue() - MinCaseVal->getValue();
// Be careful to avoid overflow when TableSize is used in
// ShouldBuildLookupTable.
if (RangeSpread.zextOrSelf(64).ugt(UINT64_MAX / 4 - 1))
return false;
uint64_t TableSize = RangeSpread.getLimitedValue() + 1;
if (!ShouldBuildLookupTable(SI, TableSize, TD, ResultTypes))
return false;