2 files changed, 30 insertions, 1 deletions
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 7b181a01c82..cf6aec0ff24 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -4240,6 +4240,13 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   }
 #endif
 
+  // Update the largest vector width if any arguments have vector types.
+  for (unsigned i = 0; i < IRCallArgs.size(); ++i) {
+    if (auto *VT = dyn_cast<llvm::VectorType>(IRCallArgs[i]->getType()))
+      LargestVectorWidth = std::max(LargestVectorWidth,
+                                    VT->getPrimitiveSizeInBits());
+  }
+
   // Compute the calling convention and attributes.
   unsigned CallingConv;
   llvm::AttributeList Attrs;
@@ -4320,6 +4327,11 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   if (!CI->getType()->isVoidTy())
     CI->setName("call");
 
+  // Update largest vector width from the return type.
+  if (auto *VT = dyn_cast<llvm::VectorType>(CI->getType()))
+    LargestVectorWidth = std::max(LargestVectorWidth,
+                                  VT->getPrimitiveSizeInBits());
+
   // Insert instrumentation or attach profile metadata at indirect call sites.
   // For more details, see the comment before the definition of
   // IPVK_IndirectCallTarget in InstrProfData.inc.
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 6249ae846dd..41bde79abab 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -430,7 +430,24 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
     NormalCleanupDest = Address::invalid();
   }
 
-  // Add the required-vector-width attribute.
+  // Scan function arguments for vector width.
+  for (llvm::Argument &A : CurFn->args())
+    if (auto *VT = dyn_cast<llvm::VectorType>(A.getType()))
+      LargestVectorWidth = std::max(LargestVectorWidth,
+                                    VT->getPrimitiveSizeInBits());
+
+  // Update vector width based on return type.
+  if (auto *VT = dyn_cast<llvm::VectorType>(CurFn->getReturnType()))
+    LargestVectorWidth = std::max(LargestVectorWidth,
+                                  VT->getPrimitiveSizeInBits());
+
+  // Add the required-vector-width attribute. This contains the max width from:
+  // 1. min-vector-width attribute used in the source program.
+  // 2. Any builtins used that have a vector width specified.
+  // 3. Values passed in and out of inline assembly.
+  // 4. Width of vector arguments and return types for this function.
+  // 5. Width of vector aguments and return types for functions called by this
+  //    function.
   if (LargestVectorWidth != 0)
     CurFn->addFnAttr("min-legal-vector-width",
                      llvm::utostr(LargestVectorWidth));