Make tblgen a little smarter about constants smaller than i32. Currently,

tblgen will complain if a sign-extended constant does not fit into a
data type smaller than i32, e.g., i16. This causes a problem when certain
hex constants are used, such as 0xff for byte masks or immediate xor
values.

tblgen will try the sign-extended value first and, if the sign extended
value would overflow, it tries to see if the unsigned value will fit.
Consequently, a software developer can now safely incant:

	(XORHIr16 R16C:$rA, 0xffff)

which is somewhat clearer and more informative than incanting:

	(XORHIr16 R16C:$rA, (i16 -1))

even if the two are bitwise equivalent.

Tblgen also outputs the 64-bit unsigned constant in the generated ISel code
when getTargetConstant() is invoked.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47188 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 0 deletions

diff --git a/include/llvm/ADT/StringExtras.h b/include/llvm/ADT/StringExtras.h
index 2a01c5f2d3..e4c941007d 100644
--- a/include/llvm/ADT/StringExtras.h
+++ b/include/llvm/ADT/StringExtras.h
@@ -85,6 +85,10 @@ static inline std::string itostr(int64_t X) {
     return utostr(static_cast<uint64_t>(X));
 }
 
+static inline std::string itohexstr(int64_t X) {
+  return utohexstr(static_cast<uint64_t>(X));
+}
+
 static inline std::string ftostr(double V) {
   char Buffer[200];
   sprintf(Buffer, "%20.6e", V);