1 files changed, 10 insertions, 11 deletions
diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
index 74b8ff91305..7bc240640a9 100644
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -4152,20 +4152,19 @@ AllocaInst *SROA::rewritePartition(AllocaInst &AI, AllocaSlices &AS,
     // FIXME: We might want to defer PHI speculation until after here.
     // FIXME: return nullptr;
   } else {
-    unsigned Alignment = AI.getAlignment();
-    if (!Alignment) {
-      // The minimum alignment which users can rely on when the explicit
-      // alignment is omitted or zero is that required by the ABI for this
-      // type.
-      Alignment = DL.getABITypeAlignment(AI.getAllocatedType());
-    }
-    Alignment = MinAlign(Alignment, P.beginOffset());
+    // If alignment is unspecified we fallback on the one required by the ABI
+    // for this type. We also make sure the alignment is compatible with
+    // P.beginOffset().
+    const Align Alignment = commonAlignment(
+        DL.getValueOrABITypeAlignment(MaybeAlign(AI.getAlignment()),
+                                      AI.getAllocatedType()),
+        P.beginOffset());
     // If we will get at least this much alignment from the type alone, leave
     // the alloca's alignment unconstrained.
-    if (Alignment <= DL.getABITypeAlignment(SliceTy))
-      Alignment = 0;
+    const bool IsUnconstrained = Alignment <= DL.getABITypeAlignment(SliceTy);
     NewAI = new AllocaInst(
-      SliceTy, AI.getType()->getAddressSpace(), nullptr, Alignment,
+        SliceTy, AI.getType()->getAddressSpace(), nullptr,
+        IsUnconstrained ? MaybeAlign() : Alignment,
         AI.getName() + ".sroa." + Twine(P.begin() - AS.begin()), &AI);
     // Copy the old AI debug location over to the new one.
     NewAI->setDebugLoc(AI.getDebugLoc());