[PATCH] D105616: [llvm-diff] Check for recursive initialiers

[Bill Wendling via Phabricator via llvm-commits]

void created this revision.
void added reviewers: rjmccall, dexonsmith, arsenm.
void requested review of this revision.
Herald added subscribers: llvm-commits, wdng.
Herald added a project: LLVM.

We need to check for recursive initializers in the "ConstantStruct"
case.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D105616

Files:
  llvm/test/tools/llvm-diff/initializers.ll
  llvm/tools/llvm-diff/DifferenceEngine.cpp


Index: llvm/tools/llvm-diff/DifferenceEngine.cpp
===================================================================
--- llvm/tools/llvm-diff/DifferenceEngine.cpp
+++ llvm/tools/llvm-diff/DifferenceEngine.cpp
@@ -490,6 +490,16 @@
         const Value *LAgg = CSL->getAggregateElement(I);
         const Value *RAgg = CSR->getAggregateElement(I);
 
+        if (LAgg == SavedLHS || RAgg == SavedRHS) {
+          if (LAgg != SavedLHS || RAgg != SavedRHS)
+            // If the left and right operands aren't both re-analyzing the
+            // variable, then the initialiers don't match, so report "false".
+            // Otherwise, we skip these operands..
+            return false;
+
+          continue;
+        }
+
         if (!equivalentAsOperands(LAgg, RAgg)) {
           return false;
         }
Index: llvm/test/tools/llvm-diff/initializers.ll
===================================================================
--- llvm/test/tools/llvm-diff/initializers.ll
+++ llvm/test/tools/llvm-diff/initializers.ll
@@ -36,3 +36,12 @@
   call void undef(%struct.mutex* @vmx_l1d_flush_mutex)
   ret i32 undef
 }
+
+; An initializer could use itself as part of the initialization.
+
+ at kvm_debugfs_entries = internal global %struct.list_head { %struct.list_head* @kvm_debugfs_entries, %struct.list_head* @kvm_debugfs_entries }, align 8
+
+define i64 @mux() {
+  %1 = load i8*, i8** bitcast (%struct.list_head* @kvm_debugfs_entries to i8**), align 8
+  ret i64 undef
+}


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