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, 12 insertions, 0 deletions

diff --git a/llvm/utils/TableGen/TGLexer.cpp b/llvm/utils/TableGen/TGLexer.cpp
index e7465de28a4..0d83e7cdf1b 100644
--- a/llvm/utils/TableGen/TGLexer.cpp
+++ b/llvm/utils/TableGen/TGLexer.cpp
@@ -20,6 +20,7 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
+#include <cerrno>
 using namespace llvm;
 
 TGLexer::TGLexer(MemoryBuffer *StartBuf) : CurLineNo(1), CurBuf(StartBuf) {
@@ -343,7 +344,18 @@ tgtok::TokKind TGLexer::LexNumber() {
       if (CurPtr == NumStart)
         return ReturnError(CurPtr-2, "Invalid hexadecimal number");
 
+      errno = 0;
       CurIntVal = strtoll(NumStart, 0, 16);
+      if (errno == EINVAL)
+        return ReturnError(CurPtr-2, "Invalid hexadecimal number");
+      if (errno == ERANGE) {
+        errno = 0;
+        CurIntVal = (int64_t)strtoull(NumStart, 0, 16);
+        if (errno == EINVAL)
+          return ReturnError(CurPtr-2, "Invalid hexadecimal number");
+        if (errno == ERANGE)
+          return ReturnError(CurPtr-2, "Hexadecimal number out of range");
+      }
       return tgtok::IntVal;
     } else if (CurPtr[0] == 'b') {
       ++CurPtr;