diff options
Diffstat (limited to 'lib/Transforms/Scalar/IndVarSimplify.cpp')
-rw-r--r-- | lib/Transforms/Scalar/IndVarSimplify.cpp | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index 38b1198..326fb38 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -17,7 +17,10 @@ // which starts at zero and steps by one. // 2. The canonical induction variable is guaranteed to be the first PHI node // in the loop header block. -// 3. Any pointer arithmetic recurrences are raised to use array subscripts. +// 3. The canonical induction variable is guaranteed to be in a wide enough +// type so that IV expressions need not be (directly) zero-extended or +// sign-extended. +// 4. Any pointer arithmetic recurrences are raised to use array subscripts. // // If the trip count of a loop is computable, this pass also makes the following // changes: @@ -296,11 +299,11 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, // If this instruction is dead now, delete it. RecursivelyDeleteTriviallyDeadInstructions(Inst); - // See if this is a single-entry LCSSA PHI node. If so, we can (and - // have to) remove - // the PHI entirely. This is safe, because the NewVal won't be variant + // If we're inserting code into the exit block rather than the + // preheader, we can (and have to) remove the PHI entirely. + // This is safe, because the NewVal won't be variant // in the loop, so we don't need an LCSSA phi node anymore. - if (NumPreds == 1) { + if (ExitBlocks.size() == 1) { PN->replaceAllUsesWith(ExitVal); RecursivelyDeleteTriviallyDeadInstructions(PN); break; |