Replace all weight-based interfaces in MBB with probability-based interfaces, and...

[oota-llvm.git] / lib / Support / BranchProbability.cpp

diff --git a/lib/Support/BranchProbability.cpp b/lib/Support/BranchProbability.cpp
index 3b0f6e6f06e42c48157190dac6b3887047e951f1..771d02c0aa3c210112721671e606c8a070070d5b 100644 (file)
--- a/lib/Support/BranchProbability.cpp
+++ b/lib/Support/BranchProbability.cpp
@@ -22,11 +22,14 @@ using namespace llvm;
 const uint32_t BranchProbability::D;
 
 raw_ostream &BranchProbability::print(raw_ostream &OS) const {
+  if (isUnknown())
+    return OS << "?%";
+
   // Get a percentage rounded to two decimal digits. This avoids
   // implementation-defined rounding inside printf.
   double Percent = rint(((double)N / D) * 100.0 * 100.0) / 100.0;
-  OS << format("0x%08" PRIx32 " / 0x%08" PRIx32 " = %.2f%%", N, D, Percent);
-  return OS;
+  return OS << format("0x%08" PRIx32 " / 0x%08" PRIx32 " = %.2f%%", N, D,
+                      Percent);
 }
 
 void BranchProbability::dump() const { print(dbgs()) << '\n'; }
@@ -43,6 +46,19 @@ BranchProbability::BranchProbability(uint32_t Numerator, uint32_t Denominator) {
   }
 }
 
+BranchProbability
+BranchProbability::getBranchProbability(uint64_t Numerator,
+                                        uint64_t Denominator) {
+  assert(Numerator <= Denominator && "Probability cannot be bigger than 1!");
+  // Scale down Denominator to fit in a 32-bit integer.
+  int Scale = 0;
+  while (Denominator > UINT32_MAX) {
+    Denominator >>= 1;
+    Scale++;
+  }
+  return BranchProbability(Numerator >> Scale, Denominator);
+}
+
 // If ConstD is not zero, then replace D by ConstD so that division and modulo
 // operations by D can be optimized, in case this function is not inlined by the
 // compiler.