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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 | 0a2e11260e6b347bcd90b0c4b192482fe1c2aa6e (patch) | |
| tree | bbceb56f016d15c7ddaf052cad9dc618401157f1 /llvm/lib/Transforms/Scalar | |
| parent | 0687b04455b0b559ec972ced988aac0dbbd30978 (diff) | |
| download | bcm5719-llvm-0a2e11260e6b347bcd90b0c4b192482fe1c2aa6e.tar.gz bcm5719-llvm-0a2e11260e6b347bcd90b0c4b192482fe1c2aa6e.zip | |
Don't unswitch really large loops even if they are mostly filled with empty
blocks.
llvm-svn: 28959
Diffstat (limited to 'llvm/lib/Transforms/Scalar')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopUnswitch.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp index d33dcb7c0b0..945803f0afc 100644 --- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/llvm/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. |
