[llvm] 163eaf3 - [CodeGen] Clean up MachineFunctionSplitter MBB safety checking (NFC)

[Daniel Hoekwater via llvm-commits]

Author: Daniel Hoekwater
Date: 2024-02-22T17:36:08Z
New Revision: 163eaf3bbc24e46a6ec9b71deda8c66f0354d2d7

URL: https://github.com/llvm/llvm-project/commit/163eaf3bbc24e46a6ec9b71deda8c66f0354d2d7
DIFF: https://github.com/llvm/llvm-project/commit/163eaf3bbc24e46a6ec9b71deda8c66f0354d2d7.diff

LOG: [CodeGen] Clean up MachineFunctionSplitter MBB safety checking (NFC)

Move the "is MBB safe to split" check out of `isColdBlock` and update
the comment since we're no longer using a temporary hack.

Added: 
    

Modified: 
    llvm/lib/CodeGen/MachineFunctionSplitter.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/MachineFunctionSplitter.cpp b/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
index 38c1c56d2823e4..0ddd9458969924 100644
--- a/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
+++ b/llvm/lib/CodeGen/MachineFunctionSplitter.cpp
@@ -109,12 +109,6 @@ static bool isColdBlock(const MachineBasicBlock &MBB,
                         const MachineBlockFrequencyInfo *MBFI,
                         ProfileSummaryInfo *PSI) {
   std::optional<uint64_t> Count = MBFI->getBlockProfileCount(&MBB);
-
-  // Temporary hack to cope with AArch64's jump table encoding
-  const TargetInstrInfo &TII = *MBB.getParent()->getSubtarget().getInstrInfo();
-  if (!TII.isMBBSafeToSplitToCold(MBB))
-    return false;
-
   // For instrumentation profiles and sample profiles, we use 
diff erent ways
   // to judge whether a block is cold and should be split.
   if (PSI->hasInstrumentationProfile() || PSI->hasCSInstrumentationProfile()) {
@@ -178,7 +172,8 @@ bool MachineFunctionSplitter::runOnMachineFunction(MachineFunction &MF) {
 
     if (MBB.isEHPad())
       LandingPads.push_back(&MBB);
-    else if (UseProfileData && isColdBlock(MBB, MBFI, PSI) && !SplitAllEHCode)
+    else if (UseProfileData && isColdBlock(MBB, MBFI, PSI) &&
+             TII.isMBBSafeToSplitToCold(MBB) && !SplitAllEHCode)
       MBB.setSectionID(MBBSectionID::ColdSectionID);
   }
 
@@ -190,7 +185,7 @@ bool MachineFunctionSplitter::runOnMachineFunction(MachineFunction &MF) {
     // Here we have UseProfileData == true.
     bool HasHotLandingPads = false;
     for (const MachineBasicBlock *LP : LandingPads) {
-      if (!isColdBlock(*LP, MBFI, PSI))
+      if (!isColdBlock(*LP, MBFI, PSI) || !TII.isMBBSafeToSplitToCold(*LP))
         HasHotLandingPads = true;
     }
     if (!HasHotLandingPads) {