Fun x86 encoding tricks: when adding an immediate value of 128,

use a SUB instruction instead of an ADD, because -128 can be
encoded in an 8-bit signed immediate field, while +128 can't be.
This avoids the need for a 32-bit immediate field in this case.

A similar optimization applies to 64-bit adds with 0x80000000,
with the 32-bit signed immediate field.

To support this, teach tablegen how to handle 64-bit constants.

llvm-svn: 57663

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/utils/TableGen/TGParser.cpp b/llvm/utils/TableGen/TGParser.cpp
index 68a1cba3da5..4ff108d2603 100644
--- a/llvm/utils/TableGen/TGParser.cpp
+++ b/llvm/utils/TableGen/TGParser.cpp
@@ -294,8 +294,8 @@ bool TGParser::ParseRangePiece(std::vector<unsigned> &Ranges) {
     TokError("expected integer or bitrange");
     return true;
   }
-  int Start = Lex.getCurIntVal();
-  int End;
+  int64_t Start = Lex.getCurIntVal();
+  int64_t End;
   
   if (Start < 0)
     return TokError("invalid range, cannot be negative");
@@ -426,7 +426,7 @@ RecTy *TGParser::ParseType() {
       TokError("expected integer in bits<n> type");
       return 0;
     }
-    unsigned Val = Lex.getCurIntVal();
+    uint64_t Val = Lex.getCurIntVal();
     if (Lex.Lex() != tgtok::greater) {  // Eat count.
       TokError("expected '>' at end of bits<n> type");
       return 0;