[Support] Add saturating multiply-add support function

Summary: Add SaturatingMultiplyAdd convenience function template since A + (X * Y) comes up frequently when doing weighted arithmetic.

Reviewers: davidxl, silvas

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D15385

llvm-svn: 257532

1 files changed, 3 insertions, 14 deletions

diff --git a/llvm/lib/ProfileData/InstrProf.cpp b/llvm/lib/ProfileData/InstrProf.cpp
index 94c701de093..d6777639abe 100644
--- a/llvm/lib/ProfileData/InstrProf.cpp
+++ b/llvm/lib/ProfileData/InstrProf.cpp
@@ -269,14 +269,8 @@ instrprof_error InstrProfValueSiteRecord::merge(InstrProfValueSiteRecord &Input,
     while (I != IE && I->Value < J->Value)
       ++I;
     if (I != IE && I->Value == J->Value) {
-      uint64_t JCount = J->Count;
       bool Overflowed;
-      if (Weight > 1) {
-        JCount = SaturatingMultiply(JCount, Weight, &Overflowed);
-        if (Overflowed)
-          Result = instrprof_error::counter_overflow;
-      }
-      I->Count = SaturatingAdd(I->Count, JCount, &Overflowed);
+      I->Count = SaturatingMultiplyAdd(J->Count, Weight, I->Count, &Overflowed);
       if (Overflowed)
         Result = instrprof_error::counter_overflow;
       ++I;
@@ -328,13 +322,8 @@ instrprof_error InstrProfRecord::merge(InstrProfRecord &Other,
 
   for (size_t I = 0, E = Other.Counts.size(); I < E; ++I) {
     bool Overflowed;
-    uint64_t OtherCount = Other.Counts[I];
-    if (Weight > 1) {
-      OtherCount = SaturatingMultiply(OtherCount, Weight, &Overflowed);
-      if (Overflowed)
-        Result = instrprof_error::counter_overflow;
-    }
-    Counts[I] = SaturatingAdd(Counts[I], OtherCount, &Overflowed);
+    Counts[I] =
+        SaturatingMultiplyAdd(Other.Counts[I], Weight, Counts[I], &Overflowed);
     if (Overflowed)
       Result = instrprof_error::counter_overflow;
   }