[SDAG] Count call argument attributes to reduce unnecessary extension (#73501)

Count how often the value is with signext/zeroext calls
when determining the preferred extension type.

1 files changed, 9 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
index 1d0a03c..1128ecf 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -64,11 +64,18 @@ static ISD::NodeType getPreferredExtendForValue(const Instruction *I) {
   // can be exposed.
   ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
   unsigned NumOfSigned = 0, NumOfUnsigned = 0;
-  for (const User *U : I->users()) {
-    if (const auto *CI = dyn_cast<CmpInst>(U)) {
+  for (const Use &U : I->uses()) {
+    if (const auto *CI = dyn_cast<CmpInst>(U.getUser())) {
       NumOfSigned += CI->isSigned();
       NumOfUnsigned += CI->isUnsigned();
     }
+    if (const auto *CallI = dyn_cast<CallBase>(U.getUser())) {
+      if (!CallI->isArgOperand(&U))
+        continue;
+      unsigned ArgNo = CallI->getArgOperandNo(&U);
+      NumOfUnsigned += CallI->paramHasAttr(ArgNo, Attribute::ZExt);
+      NumOfSigned += CallI->paramHasAttr(ArgNo, Attribute::SExt);
+    }
   }
   if (NumOfSigned > NumOfUnsigned)
     ExtendKind = ISD::SIGN_EXTEND;