[llvm] [NewGVN] Check intrinsic ID before accessing operands (PR #141571)

[Mariusz Sikora via llvm-commits]

https://github.com/mariusz-sikora-at-amd updated https://github.com/llvm/llvm-project/pull/141571

>From 1606215c998fb8e5dcb983ec6047107555700c18 Mon Sep 17 00:00:00 2001
From: Mariusz Sikora <mariusz.sikora at amd.com>
Date: Tue, 27 May 2025 05:16:46 -0400
Subject: [PATCH 1/2] [NewGVN] Check intrinsic ID before accessing operands

This patch is fixing assertions in downstream tests
---
 llvm/lib/Transforms/Scalar/NewGVN.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp
index 85bd8ef1f09a8..584cb0e89ef66 100644
--- a/llvm/lib/Transforms/Scalar/NewGVN.cpp
+++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -1530,11 +1530,12 @@ NewGVN::performSymbolicLoadCoercion(Type *LoadType, Value *LoadPtr,
   }
 
   if (auto *II = dyn_cast<IntrinsicInst>(DepInst)) {
-    auto *LifetimePtr = II->getOperand(1);
-    if (II->getIntrinsicID() == Intrinsic::lifetime_start &&
-        (LoadPtr == lookupOperandLeader(LifetimePtr) ||
-         AA->isMustAlias(LoadPtr, LifetimePtr)))
-      return createConstantExpression(UndefValue::get(LoadType));
+    if (II->getIntrinsicID() == Intrinsic::lifetime_start) {
+      auto *LifetimePtr = II->getOperand(1);
+      if (LoadPtr == lookupOperandLeader(LifetimePtr) ||
+          AA->isMustAlias(LoadPtr, LifetimePtr))
+        return createConstantExpression(UndefValue::get(LoadType));
+    }
   }
 
   // All of the below are only true if the loaded pointer is produced

>From 89328448b484fd8046c84f03154e904333da7e10 Mon Sep 17 00:00:00 2001
From: Mariusz Sikora <mariusz.sikora at amd.com>
Date: Thu, 29 May 2025 08:17:24 -0400
Subject: [PATCH 2/2] Add reproduction test

---
 .../AMDGPU/s-barrier-newgvn-compile-issue.ll    | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 llvm/test/CodeGen/AMDGPU/s-barrier-newgvn-compile-issue.ll

diff --git a/llvm/test/CodeGen/AMDGPU/s-barrier-newgvn-compile-issue.ll b/llvm/test/CodeGen/AMDGPU/s-barrier-newgvn-compile-issue.ll
new file mode 100644
index 0000000000000..ec03d1b3b2d34
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/s-barrier-newgvn-compile-issue.ll
@@ -0,0 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -passes=newgvn < %s | FileCheck %s
+
+; Test created to verify compilation without crashing.
+
+ at mem = addrspace(3) global i32 poison, align 4
+
+define i32 @foo() {
+; CHECK-LABEL: define i32 @foo() {
+; CHECK-NEXT:    call void @llvm.amdgcn.s.barrier()
+; CHECK-NEXT:    [[OUT:%.*]] = load i32, ptr addrspace(3) @mem, align 4
+; CHECK-NEXT:    ret i32 [[OUT]]
+;
+  call void @llvm.amdgcn.s.barrier()
+  %out = load i32, ptr addrspace(3) @mem, align 4
+  ret i32 %out
+}