[llvm-mca] Delay calculation of Cycles per Resources, separate the cycles and resource quantities.

Summary:
This patch removes the storing of accumulated floating point data 
within the llvm-mca library.

This patch splits-up the two quantities: cycles and number of resource units.
By splitting-up these two quantities, we delay the calculation of "cycles per resource unit"
until that value is read, reducing the chance of accumulating floating point error. 

I considered using the APFloat, but after measuring performance, for a large (many iteration)
sample, I decided to go with this faster solution.

Reviewers: andreadb, courbet, RKSimon

Reviewed By: andreadb

Subscribers: llvm-commits, javed.absar, tschuett, gbedwell

Differential Revision: https://reviews.llvm.org/D51903

llvm-svn: 341980

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/tools/llvm-mca/include/HardwareUnits/ResourceManager.h b/llvm/tools/llvm-mca/include/HardwareUnits/ResourceManager.h
index c3f893660eb..dfac15f53fc 100644
--- a/llvm/tools/llvm-mca/include/HardwareUnits/ResourceManager.h
+++ b/llvm/tools/llvm-mca/include/HardwareUnits/ResourceManager.h
@@ -17,6 +17,7 @@
 #define LLVM_TOOLS_LLVM_MCA_RESOURCE_MANAGER_H
 
 #include "Instruction.h"
+#include "Support.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
@@ -344,7 +345,7 @@ public:
 
   void issueInstruction(
       const InstrDesc &Desc,
-      llvm::SmallVectorImpl<std::pair<ResourceRef, double>> &Pipes);
+      llvm::SmallVectorImpl<std::pair<ResourceRef, ResourceCycles>> &Pipes);
 
   void cycleEvent(llvm::SmallVectorImpl<ResourceRef> &ResourcesFreed);