[IslExprBuilder] Allow 64-bit ints in hasLargeInts()

[cs15btech11044]

Summary

This patch allows for 64-bit integers to be not considered as a large int.

The bug came up because the invalid context was not evaluated properly during Chapel+Polly GSoC effort.

[cs15btech11044]

All the regression tests pass successfully.

[Meinersbur]

To add some details: The original failure was external/skia/src/gpu/GrTestUtils.cpp of the aosp buildbot. It expects a library function __muloti4 which was lowered from the intrinsic llvm.smul.with.overflow.i128. The next smaller llvm.smul.with.overflow.i64 should be able to handle 64 bit values (not just 63 bits).

lib/CodeGen/IslExprBuilder.cpp

bool IslExprBuilder::hasLargeInts(isl::ast_expr Expr) {
 
   if (Type == isl_ast_expr_id)
     return false;
 
   if (Type == isl_ast_expr_int) {
     isl::val Val = Expr.get_val();
     APInt APValue = APIntFromVal(Val);
     auto BitWidth = APValue.getBitWidth();
-    return BitWidth >= 64;
+    return BitWidth > 64;
   }
 
   assert(Type == isl_ast_expr_op && "Expected isl_ast_expr of type operation");
 
   int NumArgs = isl_ast_expr_get_op_n_arg(Expr.get());
 
   for (int i = 0; i < NumArgs; i++) {
     isl::ast_expr Operand = Expr.get_op_arg(i);