[clang] [llvm] Case handling MachineOperandType address of a global value in SIFoldOperands (PR #135404)

[Akhilesh Moorthy via cfe-commits]

https://github.com/isakhilesh created https://github.com/llvm/llvm-project/pull/135404

While `FoldingImmLike` accepts `MO_Immediate`, `MO_FrameIndex` and `MO_GlobalAddress`, the conditional block after it only covers the first 2, so I have added a case for the global value as well.


>From 116e14cfa6274b00da641be60f8db7444588b990 Mon Sep 17 00:00:00 2001
From: Malavika Samak <malavika.samak at gmail.com>
Date: Thu, 10 Apr 2025 11:00:02 -0700
Subject: [PATCH] Case handling MachineOperandType address of a global value in
 SIFoldOperands

While `FoldingImmLike` accepts `MO_Immediate`, `MO_FrameIndex` and `MO_GlobalAddress`, the conditional block after it only covers the first 2, so I have added a case for the global value as well.
---
 clang/include/clang/Basic/AttrDocs.td     | 8 +++++---
 llvm/lib/Target/AMDGPU/SIFoldOperands.cpp | 4 +++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index c8b371280e35d..97a5f24d35d7d 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -7517,9 +7517,11 @@ the field it is attached to, and it may also lead to emission of automatic fix-i
 hints which would help the user replace the use of unsafe functions(/fields) with safe
 alternatives, though the attribute can be used even when the fix can't be automated.
 
-* Attribute attached to functions: The attribute does not suppress
-  ``-Wunsafe-buffer-usage`` inside the function to which it is attached.
-  These warnings still need to be addressed.
+* Attribute attached to functions: The attribute suppresses all
+  ``-Wunsafe-buffer-usage`` warnings within the function it is attached to, as the
+  function is now classified as unsafe. The attribute should be used carefully, as it
+  will silence all unsafe operation warnings inside the function; including any new
+  unsafe operations introduced in the future.
 
   The attribute is warranted even if the only way a function can overflow
   the buffer is by violating the function's preconditions. For example, it
diff --git a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
index d6acf9e081b9f..701d17930d7df 100644
--- a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
@@ -1161,8 +1161,10 @@ void SIFoldOperandsImpl::foldOperand(
 
         if (OpToFold.isImm())
           UseMI->getOperand(1).ChangeToImmediate(OpToFold.getImm());
-        else
+        else if(OpToFold.isFI())
           UseMI->getOperand(1).ChangeToFrameIndex(OpToFold.getIndex());
+        else if(OpToFold.isGlobal())
+          return;
         UseMI->removeOperand(2); // Remove exec read (or src1 for readlane)
         return;
       }