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Do compare constant SCEV values in SCEVComplexityCompare, because 

even though the order doesn't matter at the top level of an expression,
it does matter when the constant is a subexpression of an n-ary
expression, because n-ary expressions are sorted lexicographically.

llvm-svn: 73358
This commit is contained in:
Dan Gohman 2009-06-14 22:51:25 +00:00
parent 0652fd59ff
commit 862b7d98d1
1 changed files with 12 additions and 3 deletions
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15
llvm/lib/Analysis/ScalarEvolution.cpp
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@ -504,9 +504,18 @@ namespace {
return false;
}
// Constant sorting doesn't matter since they'll be folded.
if (isa<SCEVConstant>(LHS))
return false;
// Compare constant values.
if (const SCEVConstant *LC = dyn_cast<SCEVConstant>(LHS)) {
const SCEVConstant *RC = cast<SCEVConstant>(RHS);
return LC->getValue()->getValue().ult(RC->getValue()->getValue());
}
// Compare addrec loop depths.
if (const SCEVAddRecExpr *LA = dyn_cast<SCEVAddRecExpr>(LHS)) {
const SCEVAddRecExpr *RA = cast<SCEVAddRecExpr>(RHS);
if (LA->getLoop()->getLoopDepth() != RA->getLoop()->getLoopDepth())
return LA->getLoop()->getLoopDepth() < RA->getLoop()->getLoopDepth();
}
// Lexicographically compare n-ary expressions.
if (const SCEVNAryExpr *LC = dyn_cast<SCEVNAryExpr>(LHS)) {