[clang] [Headers][X86] VisitCallExpr constexpr immediate shifts (#154293) (PR #155542)

[Simon Pilgrim via cfe-commits]

================
@@ -11644,64 +11679,181 @@ bool VectorExprEvaluator::VisitCallExpr(const CallExpr *E) {
 
     for (unsigned EltNum = 0; EltNum < SourceLen; ++EltNum) {
       APSInt LHS = SourceLHS.getVectorElt(EltNum).getInt();
-      APSInt RHS = SourceRHS.getVectorElt(EltNum).getInt();
-      switch (E->getBuiltinCallee()) {
-      case Builtin::BI__builtin_elementwise_add_sat:
-        ResultElements.push_back(APValue(
-            APSInt(LHS.isSigned() ? LHS.sadd_sat(RHS) : LHS.uadd_sat(RHS),
-                   DestUnsigned)));
-        break;
-      case Builtin::BI__builtin_elementwise_sub_sat:
-        ResultElements.push_back(APValue(
-            APSInt(LHS.isSigned() ? LHS.ssub_sat(RHS) : LHS.usub_sat(RHS),
-                   DestUnsigned)));
-        break;
-      case clang::X86::BI__builtin_ia32_pmulhuw128:
-      case clang::X86::BI__builtin_ia32_pmulhuw256:
-      case clang::X86::BI__builtin_ia32_pmulhuw512:
-        ResultElements.push_back(APValue(APSInt(llvm::APIntOps::mulhu(LHS, RHS),
-                                                /*isUnsigned=*/true)));
-        break;
-      case clang::X86::BI__builtin_ia32_pmulhw128:
-      case clang::X86::BI__builtin_ia32_pmulhw256:
-      case clang::X86::BI__builtin_ia32_pmulhw512:
-        ResultElements.push_back(APValue(APSInt(llvm::APIntOps::mulhs(LHS, RHS),
-                                                /*isUnsigned=*/false)));
-        break;
-      case clang::X86::BI__builtin_ia32_psllv2di:
-      case clang::X86::BI__builtin_ia32_psllv4di:
-      case clang::X86::BI__builtin_ia32_psllv4si:
-      case clang::X86::BI__builtin_ia32_psllv8si:
-        if (RHS.uge(RHS.getBitWidth())) {
-          ResultElements.push_back(
-              APValue(APSInt(APInt::getZero(RHS.getBitWidth()), DestUnsigned)));
+
+      if (SourceRHS.isInt()) {
+        uint64_t LaneWidth = 0;
----------------
RKSimon wrote:

this should be computable from LHS.getBitWidth()

https://github.com/llvm/llvm-project/pull/155542