[llvm] [BFI] Compute the minimum frequency only when dumping. NFC (PR #212957)

[Fangrui Song via llvm-commits]

https://github.com/MaskRay created https://github.com/llvm/llvm-project/pull/212957

None

>From 92cceacb61db44a20163634760e2685d1a2684b3 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Wed, 29 Jul 2026 23:52:41 -0700
Subject: [PATCH] [BFI] Compute the minimum frequency only when dumping. NFC

---
 llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp | 29 +++++++++-----------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp b/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
index 1e7d7c9ce8d51..4680af8f50c2b 100644
--- a/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
+++ b/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
@@ -479,8 +479,11 @@ void BlockFrequencyInfoImplBase::distributeMass(const BlockNode &Source,
   }
 }
 
-static void convertFloatingToInteger(BlockFrequencyInfoImplBase &BFI,
-                                     const Scaled64 &Min, const Scaled64 &Max) {
+static void convertFloatingToInteger(BlockFrequencyInfoImplBase &BFI) {
+  auto Max = Scaled64::getZero();
+  for (const FrequencyData &F : BFI.Freqs)
+    Max = std::max(Max, F.Scaled);
+
   // Scale the Factor to a size that creates integers.  If possible scale
   // integers so that Max == UINT64_MAX so that they can be best differentiated.
   // It is possible that the range between min and max cannot be accurately
@@ -496,9 +499,13 @@ static void convertFloatingToInteger(BlockFrequencyInfoImplBase &BFI,
   Scaled64 ScalingFactor = Scaled64(1, MaxBits - Slack) / Max;
 
   // Translate the floats to integers.
-  LLVM_DEBUG(dbgs() << "float-to-int: min = " << Min << ", max = " << Max
-                    << ", factor = " << ScalingFactor << "\n");
-  (void)Min;
+  LLVM_DEBUG({
+    auto Min = Scaled64::getLargest();
+    for (const FrequencyData &F : BFI.Freqs)
+      Min = std::min(Min, F.Scaled);
+    dbgs() << "float-to-int: min = " << Min << ", max = " << Max
+           << ", factor = " << ScalingFactor << "\n";
+  });
   for (size_t Index = 0; Index < BFI.Freqs.size(); ++Index) {
     Scaled64 Scaled = BFI.Freqs[Index].Scaled * ScalingFactor;
     BFI.Freqs[Index].Integer = std::max(UINT64_C(1), Scaled.toInt<uint64_t>());
@@ -544,18 +551,8 @@ void BlockFrequencyInfoImplBase::unwrapLoops() {
 }
 
 void BlockFrequencyInfoImplBase::finalizeMetrics() {
-  // Unwrap loop packages in reverse post-order, tracking min and max
-  // frequencies.
-  auto Min = Scaled64::getLargest();
-  auto Max = Scaled64::getZero();
-  for (size_t Index = 0; Index < Working.size(); ++Index) {
-    // Update min/max scale.
-    Min = std::min(Min, Freqs[Index].Scaled);
-    Max = std::max(Max, Freqs[Index].Scaled);
-  }
-
   // Convert to integers.
-  convertFloatingToInteger(*this, Min, Max);
+  convertFloatingToInteger(*this);
 
   // Clean up data structures.
   cleanup(*this);