Prefer multiplications to divisions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129080 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SpillPlacement.cpp b/lib/CodeGen/SpillPlacement.cpp
index ac7a192..cab18a1 100644
--- a/lib/CodeGen/SpillPlacement.cpp
+++ b/lib/CodeGen/SpillPlacement.cpp
@@ -67,11 +67,11 @@
/// because all weights are positive.
///
struct SpillPlacement::Node {
- /// Frequency - Total block frequency feeding into[0] or out of[1] the bundle.
+ /// Scale - Inverse block frequency feeding into[0] or out of[1] the bundle.
/// Ideally, these two numbers should be identical, but inaccuracies in the
/// block frequency estimates means that we need to normalize ingoing and
/// outgoing frequencies separately so they are commensurate.
- float Frequency[2];
+ float Scale[2];
/// Bias - Normalized contributions from non-transparent blocks.
/// A bundle connected to a MustSpill block has a huge negative bias,
@@ -107,7 +107,7 @@
/// Node - Create a blank Node.
Node() {
- Frequency[0] = Frequency[1] = 0;
+ Scale[0] = Scale[1] = 0;
}
/// clear - Reset per-query data, but preserve frequencies that only depend on
@@ -121,7 +121,7 @@
/// out=0 for an ingoing link, and 1 for an outgoing link.
void addLink(unsigned b, float w, bool out) {
// Normalize w relative to all connected blocks from that direction.
- w /= Frequency[out];
+ w *= Scale[out];
// There can be multiple links to the same bundle, add them up.
for (LinkVector::iterator I = Links.begin(), E = Links.end(); I != E; ++I)
@@ -137,7 +137,7 @@
/// Return the change to the total number of positive biases.
int addBias(float w, bool out) {
// Normalize w relative to all connected blocks from that direction.
- w /= Frequency[out];
+ w *= Scale[out];
int Before = Bias > 0;
Bias += w;
int After = Bias > 0;
@@ -185,10 +185,16 @@
loops->getLoopDepth(I));
unsigned Num = I->getNumber();
BlockFrequency[Num] = Freq;
- nodes[bundles->getBundle(Num, 1)].Frequency[0] += Freq;
- nodes[bundles->getBundle(Num, 0)].Frequency[1] += Freq;
+ nodes[bundles->getBundle(Num, 1)].Scale[0] += Freq;
+ nodes[bundles->getBundle(Num, 0)].Scale[1] += Freq;
}
+ // Scales are reciprocal frequencies.
+ for (unsigned i = 0, e = bundles->getNumBundles(); i != e; ++i)
+ for (unsigned d = 0; d != 2; ++d)
+ if (nodes[i].Scale[d] > 0)
+ nodes[i].Scale[d] = 1 / nodes[i].Scale[d];
+
// We never change the function.
return false;
}