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author | Nick Lewycky <nicholas@mxc.ca> | 2008-12-12 17:09:07 +0000 |
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committer | Nick Lewycky <nicholas@mxc.ca> | 2008-12-12 17:09:07 +0000 |
commit | 8bdc6920cdd1fd51e5af1537462c30c06203fe85 (patch) | |
tree | b28264eb33335ccb589ebda6716bfbff0ff731ed /lib | |
parent | 712f7b3f549644190e90210a07988753f53daa0a (diff) | |
download | external_llvm-8bdc6920cdd1fd51e5af1537462c30c06203fe85.zip external_llvm-8bdc6920cdd1fd51e5af1537462c30c06203fe85.tar.gz external_llvm-8bdc6920cdd1fd51e5af1537462c30c06203fe85.tar.bz2 |
Revert my re-instated reverted commit, fixes the bootstrap build on x86-64 linux.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60951 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 1dd5026..2b714de 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -2924,12 +2924,8 @@ bool ScalarEvolutionsImpl::potentialInfiniteLoop(SCEV *Stride, SCEV *RHS, if (!R) return true; - if (isSigned) { - if (SC->getValue()->isOne()) - return R->getValue()->isMaxValue(true); - + if (isSigned) return true; // XXX: because we don't have an sdiv scev. - } // If negative, it wraps around every iteration, but we don't care about that. APInt S = SC->getValue()->getValue().abs(); @@ -2975,6 +2971,14 @@ HowManyLessThans(SCEV *LHS, SCEV *RHS, const Loop *L, // run (m-n)/s times. SCEVHandle End = RHS; + if (!executesAtLeastOnce(L, isSigned, trueWhenEqual, + SE.getMinusSCEV(Start, One), RHS)) { + // If not, we get the value of the LHS in the first iteration in which + // the above condition doesn't hold. This equals to max(m,n). + End = isSigned ? SE.getSMaxExpr(RHS, Start) + : SE.getUMaxExpr(RHS, Start); + } + // If the expression is less-than-or-equal to, we need to extend the // loop by one iteration. // @@ -2983,16 +2987,12 @@ HowManyLessThans(SCEV *LHS, SCEV *RHS, const Loop *L, // division would equal one, but the loop runs twice putting the // induction variable at 12. - if (trueWhenEqual) - End = SE.getAddExpr(End, One); - - if (!executesAtLeastOnce(L, isSigned, trueWhenEqual, - SE.getMinusSCEV(Start, One), RHS)) { - // If not, we get the value of the LHS in the first iteration in which - // the above condition doesn't hold. This equals to max(m,n). - End = isSigned ? SE.getSMaxExpr(End, Start) - : SE.getUMaxExpr(End, Start); - } + if (!trueWhenEqual) + // (Stride - 1) is correct only because we know it's unsigned. + // What we really want is to decrease the magnitude of Stride by one. + Start = SE.getMinusSCEV(Start, SE.getMinusSCEV(Stride, One)); + else + Start = SE.getMinusSCEV(Start, Stride); // Finally, we subtract these two values to get the number of times the // backedge is executed: max(m,n)-n. |