[llvm] 81e0799 - [AMDGPU][SIInsertWaitcnts] don't crash when printing messages at end of block (#145694)

[via llvm-commits]

Author: Sameer Sahasrabuddhe
Date: 2025-06-25T20:59:55+05:30
New Revision: 81e07996aa8b818ec72c110ac98a98a450de4aee

URL: https://github.com/llvm/llvm-project/commit/81e07996aa8b818ec72c110ac98a98a450de4aee
DIFF: https://github.com/llvm/llvm-project/commit/81e07996aa8b818ec72c110ac98a98a450de4aee.diff

LOG: [AMDGPU][SIInsertWaitcnts] don't crash when printing messages at end of block (#145694)

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp b/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp
index f43831016952a..41e1f0586e36c 100644
--- a/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp
@@ -1353,7 +1353,13 @@ bool WaitcntGeneratorPreGFX12::applyPreexistingWaitcnt(
   MachineInstr *WaitcntInstr = nullptr;
   MachineInstr *WaitcntVsCntInstr = nullptr;
 
-  LLVM_DEBUG(dbgs() << "PreGFX12::applyPreexistingWaitcnt at: " << *It);
+  LLVM_DEBUG({
+    dbgs() << "PreGFX12::applyPreexistingWaitcnt at: ";
+    if (It == OldWaitcntInstr.getParent()->instr_end())
+      dbgs() << "end of block\n";
+    else
+      dbgs() << *It;
+  });
 
   for (auto &II :
        make_early_inc_range(make_range(OldWaitcntInstr.getIterator(), It))) {
@@ -1507,7 +1513,13 @@ bool WaitcntGeneratorGFX12Plus::applyPreexistingWaitcnt(
   MachineInstr *CombinedStoreDsCntInstr = nullptr;
   MachineInstr *WaitInstrs[NUM_EXTENDED_INST_CNTS] = {};
 
-  LLVM_DEBUG(dbgs() << "GFX12Plus::applyPreexistingWaitcnt at: " << *It);
+  LLVM_DEBUG({
+    dbgs() << "GFX12Plus::applyPreexistingWaitcnt at: ";
+    if (It == OldWaitcntInstr.getParent()->instr_end())
+      dbgs() << "end of block\n";
+    else
+      dbgs() << *It;
+  });
 
   for (auto &II :
        make_early_inc_range(make_range(OldWaitcntInstr.getIterator(), It))) {