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| author | Chris Lattner <sabre@nondot.org> | 2006-06-28 16:38:55 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2006-06-28 16:38:55 +0000 |
| commit | daa2bf9a192496a456b548fbb6787cdcee183c70 (patch) | |
| tree | baa796143d1c44da31a3332efe910de69be1717c /lib | |
| parent | ee12e8f28dc520cbc98555bc18749c2828c05495 (diff) | |
| download | llvm-daa2bf9a192496a456b548fbb6787cdcee183c70.tar.gz llvm-daa2bf9a192496a456b548fbb6787cdcee183c70.tar.bz2 llvm-daa2bf9a192496a456b548fbb6787cdcee183c70.tar.xz | |
Don't unswitch really large loops even if they are mostly filled with empty
blocks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28959 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/LoopUnswitch.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp index d33dcb7c0b..945803f0af 100644 --- a/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/lib/Transforms/Scalar/LoopUnswitch.cpp @@ -333,6 +333,12 @@ unsigned LoopUnswitch::getLoopUnswitchCost(Loop *L, Value *LIC) { if (IsTrivialUnswitchCondition(L, LIC)) return 0; + // If the loop is really large (over twice our threshold) don't even consider + // unswitching it. This will produce a really large loop with lots of empty + // blocks. + if (L->getBlocks().size() > 2*Threshold) + return 2*Threshold; + unsigned Cost = 0; // FIXME: this is brain dead. It should take into consideration code // shrinkage. |