[ESIMD] Fix a crash lowering __esimd_unpack_mask (#3196)

Co-authored-by: kbobrovs <[email protected]>

Author: DenisBakhvalov

llvm/lib/SYCLLowerIR/LowerESIMD.cpp

@@ -726,7 +726,8 @@ static void translateUnPackMask(CallInst &CI) {
   llvm::Value *TransCI = Builder.CreateZExt(
       Arg0, llvm::FixedVectorType::get(llvm::Type::getInt16Ty(Context), N));
   TransCI->takeName(&CI);
-  cast<llvm::Instruction>(TransCI)->setDebugLoc(CI.getDebugLoc());
+  if (llvm::Instruction *TransCInst = dyn_cast<llvm::Instruction>(TransCI))
+    TransCInst->setDebugLoc(CI.getDebugLoc());
   CI.replaceAllUsesWith(TransCI);
 }
 

llvm/test/SYCLLowerIR/esimd_lower_crash_zext.ll

@@ -0,0 +1,15 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -LowerESIMD -S < %s | FileCheck %s
+
+; This test checks that there is no crash while lowering 
+; __esimd_unpack_mask when its argument is an integer constant.
+
+define spir_func <32 x i16> @_Z3foov() {
+; CHECK-LABEL: @_Z3foov(
+; CHECK-NEXT:    ret <32 x i16> zext (<32 x i1> bitcast (<1 x i32> <i32 1717986918> to <32 x i1>) to <32 x i16>)
+;
+  %call.i.i = call spir_func <32 x i16> @_Z19__esimd_unpack_maskILi32EEN2cl4sycl5INTEL3gpu11vector_typeItXT_EE4typeEj(i32 1717986918)
+  ret <32 x i16> %call.i.i
+}
+
+declare dso_local spir_func <32 x i16> @_Z19__esimd_unpack_maskILi32EEN2cl4sycl5INTEL3gpu11vector_typeItXT_EE4typeEj(i32)