[PATCH] D85881: Fix PR45442: Bail out when MemorySSA information is not available

[Aditya Kumar via Phabricator via llvm-commits]

hiraditya updated this revision to Diff 285422.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85881/new/

https://reviews.llvm.org/D85881

Files:
  llvm/lib/Transforms/Scalar/GVNHoist.cpp
  llvm/test/Transforms/GVNHoist/pr45442.ll


Index: llvm/test/Transforms/GVNHoist/pr45442.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/GVNHoist/pr45442.ll
@@ -0,0 +1,32 @@
+; RUN: opt < %s -gvn-hoist -S | FileCheck %s
+
+; gvn-hoist shouldn't crash in this case.
+; CHECK-LABEL: @func(i1 %b)
+; CHECK:       entry:
+; CHECK-NEXT:  br i1
+; CHECK:  bb1:
+; CHECK-NEXT:  ret void
+; CHECK:  bb2:
+; CHECK-NEXT:  call
+; CHECK-NEXT:  call
+; CHECK-NEXT:  ret void
+
+define void @v_1_0() #0 {
+entry:
+  ret void
+}
+
+define void @func(i1 %b) {
+entry:
+  br i1 undef, label %bb1, label %bb2
+
+bb1:
+  ret void
+
+bb2:
+  call void @v_1_0()
+  call void @v_1_0()
+  ret void
+}
+
+attributes #0 = { nounwind readonly }
Index: llvm/lib/Transforms/Scalar/GVNHoist.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/GVNHoist.cpp
+++ llvm/lib/Transforms/Scalar/GVNHoist.cpp
@@ -605,9 +605,10 @@
         if (safeToHoistScalar(BB, Insn->getParent(), NumBBsOnAllPaths))
           Safe.push_back(CHI);
       } else {
-        MemoryUseOrDef *UD = MSSA->getMemoryAccess(Insn);
-        if (safeToHoistLdSt(BB->getTerminator(), Insn, UD, K, NumBBsOnAllPaths))
-          Safe.push_back(CHI);
+        auto T = BB->getTerminator();
+        if (MemoryUseOrDef *UD = MSSA->getMemoryAccess(Insn))
+          if (safeToHoistLdSt(T, Insn, UD, K, NumBBsOnAllPaths))
+            Safe.push_back(CHI);
       }
     }
   }


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