[PGO] CallPromotion: Don't try to pass sret args to varargs functions

It's not allowed by the verifier.

Differential revision: https://reviews.llvm.org/D81409

1 files changed, 14 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/CallPromotionUtils.cpp b/llvm/lib/Transforms/Utils/CallPromotionUtils.cpp
index a7a0290..5a47c1f 100644
--- a/llvm/lib/Transforms/Utils/CallPromotionUtils.cpp
+++ b/llvm/lib/Transforms/Utils/CallPromotionUtils.cpp
@@ -403,9 +403,12 @@ bool llvm::isLegalToPromote(const CallBase &CB, Function *Callee,
   // The number of formal arguments of the callee.
   unsigned NumParams = Callee->getFunctionType()->getNumParams();
 
+  // The number of actual arguments in the call.
+  unsigned NumArgs = CB.arg_size();
+
   // Check the number of arguments. The callee and call site must agree on the
   // number of arguments.
-  if (CB.arg_size() != NumParams && !Callee->isVarArg()) {
+  if (NumArgs != NumParams && !Callee->isVarArg()) {
     if (FailureReason)
       *FailureReason = "The number of arguments mismatch";
     return false;
@@ -414,7 +417,8 @@ bool llvm::isLegalToPromote(const CallBase &CB, Function *Callee,
   // Check the argument types. The callee's formal argument types must be
   // bitcast compatible with the corresponding actual argument types of the call
   // site.
-  for (unsigned I = 0; I < NumParams; ++I) {
+  unsigned I = 0;
+  for (; I < NumParams; ++I) {
     Type *FormalTy = Callee->getFunctionType()->getFunctionParamType(I);
     Type *ActualTy = CB.getArgOperand(I)->getType();
     if (FormalTy == ActualTy)
@@ -425,6 +429,14 @@ bool llvm::isLegalToPromote(const CallBase &CB, Function *Callee,
       return false;
     }
   }
+  for (; I < NumArgs; I++) {
+    // Vararg functions can have more arguments than paramters.
+    assert(Callee->isVarArg());
+    if (CB.paramHasAttr(I, Attribute::StructRet)) {
+      *FailureReason = "SRet arg to vararg function";
+      return false;
+    }
+  }
 
   return true;
 }