#define DEBUG_TYPE "spillplacement"
#include "SpillPlacement.h"
+#include "llvm/ADT/BitVector.h"
#include "llvm/CodeGen/EdgeBundles.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
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;
}
0, // DontCare,
1, // PrefReg,
-1, // PrefSpill
+ 0, // PrefBoth
-HUGE_VALF // MustSpill
};
}
}
+/// addPrefSpill - Same as addConstraints(PrefSpill)
+void SpillPlacement::addPrefSpill(ArrayRef<unsigned> Blocks, bool Strong) {
+ for (ArrayRef<unsigned>::iterator I = Blocks.begin(), E = Blocks.end();
+ I != E; ++I) {
+ float Freq = getBlockFrequency(*I);
+ if (Strong)
+ Freq += Freq;
+ unsigned ib = bundles->getBundle(*I, 0);
+ unsigned ob = bundles->getBundle(*I, 1);
+ activate(ib);
+ activate(ob);
+ nodes[ib].addBias(-Freq, 1);
+ nodes[ob].addBias(-Freq, 0);
+ }
+}
+
void SpillPlacement::addLinks(ArrayRef<unsigned> Links) {
for (ArrayRef<unsigned>::iterator I = Links.begin(), E = Links.end(); I != E;
++I) {