diff options
| -rw-r--r-- | include/llvm/CodeGen/EdgeBundles.h | 2 | ||||
| -rw-r--r-- | lib/CodeGen/SpillPlacement.cpp | 11 |
2 files changed, 12 insertions, 1 deletions
diff --git a/include/llvm/CodeGen/EdgeBundles.h b/include/llvm/CodeGen/EdgeBundles.h index a1d29b1f02..e8a4a2d2d8 100644 --- a/include/llvm/CodeGen/EdgeBundles.h +++ b/include/llvm/CodeGen/EdgeBundles.h @@ -46,7 +46,7 @@ public: unsigned getNumBundles() const { return EC.getNumClasses(); } /// getBlocks - Return an array of blocks that are connected to Bundle. - ArrayRef<unsigned> getBlocks(unsigned Bundle) { return Blocks[Bundle]; } + ArrayRef<unsigned> getBlocks(unsigned Bundle) const { return Blocks[Bundle]; } /// getMachineFunction - Return the last machine function computed. const MachineFunction *getMachineFunction() const { return MF; } diff --git a/lib/CodeGen/SpillPlacement.cpp b/lib/CodeGen/SpillPlacement.cpp index 6f33f5465c..320128a999 100644 --- a/lib/CodeGen/SpillPlacement.cpp +++ b/lib/CodeGen/SpillPlacement.cpp @@ -207,6 +207,17 @@ void SpillPlacement::activate(unsigned n) { return; ActiveNodes->set(n); nodes[n].clear(); + + // Very large bundles usually come from big switches, indirect branches, + // landing pads, or loops with many 'continue' statements. It is difficult to + // allocate registers when so many different blocks are involved. + // + // Give a small negative bias to large bundles such that 1/32 of the + // connected blocks need to be interested before we consider expanding the + // region through the bundle. This helps compile time by limiting the number + // of blocks visited and the number of links in the Hopfield network. + if (bundles->getBlocks(n).size() > 100) + nodes[n].Bias = -0.0625f; } |