[llvm] [Support] Always scale InstructionCost::Value (PR #178962)

[Ryan Buchner via llvm-commits]

================
@@ -11,14 +11,21 @@
 /// instructions.
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Support/Format.h"
 #include "llvm/Support/InstructionCost.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
 void InstructionCost::print(raw_ostream &OS) const {
-  if (isValid())
-    OS << Value;
-  else
+  if (isValid()) {
+    if (Value % CostGranularity) {
+      double DecimalValue = static_cast<double>(Value) / CostGranularity;
+      OS << format("%.2f", DecimalValue) << " (" << Value << "/" << CostGranularity << ")";
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bababuck wrote:

I had left it to make the denominator explicit to the user, but I think its reasonable to remove given the current decimal result is exact.

https://github.com/llvm/llvm-project/pull/178962