[CodeGenPrepare] Fix crash with null PSI

[nataliakokoromyti]

this PR fixes a crash in CodeGenPrepare when PSI is null.

Fixes #173360.

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[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: None (nataliakokoromyti)

Changes

this PR fixes a crash in CodeGenPrepare when PSI is null.

---

Full diff: https://github.com/llvm/llvm-project/pull/173385.diff

1 Files Affected:

• (added) llvm/test/Transforms/CodeGenPrepare/pr173360-null-psi.ll (+21)

diff --git a/llvm/test/Transforms/CodeGenPrepare/pr173360-null-psi.ll b/llvm/test/Transforms/CodeGenPrepare/pr173360-null-psi.ll
new file mode 100644
index 0000000000000..53500c0bcb481
--- /dev/null
+++ b/llvm/test/Transforms/CodeGenPrepare/pr173360-null-psi.ll
@@ -0,0 +1,21 @@
+; NOTE: This test verifies that CodeGenPrepare doesn't crash when PSI is null
+; RUN: opt -passes=codegenprepare < %s -S | FileCheck %s
+;
+; This test case triggered a null pointer dereference in CodeGenPrepare::_run()
+; when ProfileSummaryInfo (PSI) was not available. The pass attempted to call
+; PSI->hasHugeWorkingSetSize() without checking if PSI was null.
+;
+; The fix adds null checks before dereferencing PSI.
+; See: https://github.com/llvm/llvm-project/issues/173360
+
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: @f(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    %iv.next.reg2mem = alloca i32, align 4
+; CHECK-NEXT:    ret void
+define void @f(ptr %A, i32 %n) {
+entry:
+  %iv.next.reg2mem = alloca i32, align 4
+  ret void
+}

[zwuis]

Where is the fix? Only test file is modified.

[nikic]

Please also add a test.

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff origin/main HEAD --extensions cpp -- llvm/lib/CodeGen/CodeGenPrepare.cpp --diff_from_common_commit

⚠️
The reproduction instructions above might return results for more than one PR
in a stack if you are using a stacked PR workflow. You can limit the results by
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⚠️

View the diff from clang-format here.

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index aa645d87f..ee1ad6de5 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -605,7 +605,8 @@ bool CodeGenPrepare::_run(Function &F) {
 
   /// This optimization identifies DIV instructions that can be
   /// profitably bypassed and carried out with a shorter, faster divide.
-  if (!OptSize && PSI && !PSI->hasHugeWorkingSetSize() && TLI->isSlowDivBypassed()) {
+  if (!OptSize && PSI && !PSI->hasHugeWorkingSetSize() &&
+      TLI->isSlowDivBypassed()) {
     const DenseMap<unsigned int, unsigned int> &BypassWidths =
         TLI->getBypassSlowDivWidths();
     BasicBlock *BB = &*F.begin();