Handle 'thin' callees in extractStringConcatOperands

Author: Joe Shajrawi

lib/SILOptimizer/Utils/Local.cpp

@@ -677,8 +677,6 @@ bool StringConcatenationOptimizer::extractStringConcatOperands() {
   if (AI->getNumArguments() != 3 || !Fn->hasSemanticsAttr("string.concat"))
     return false;
 
-  assert(Fn->getRepresentation() == SILFunctionTypeRepresentation::Method);
-
   // Left and right operands of a string concatenation operation.
   AILeft = dyn_cast<ApplyInst>(AI->getOperand(1));
   AIRight = dyn_cast<ApplyInst>(AI->getOperand(2));
@@ -719,11 +717,6 @@ bool StringConcatenationOptimizer::extractStringConcatOperands() {
          AIRightOperandsNum == 5)))
     return false;
 
-  assert(FRILeftFun->getRepresentation() ==
-         SILFunctionTypeRepresentation::Method);
-  assert(FRIRightFun->getRepresentation() ==
-         SILFunctionTypeRepresentation::Method);
-
   SLILeft = dyn_cast<StringLiteralInst>(AILeft->getOperand(1));
   SLIRight = dyn_cast<StringLiteralInst>(AIRight->getOperand(1));