The powers that be have decided that LLVM IR should now support 16-bit

"half precision" floating-point with a first-class type.

This patch adds basic IR support (but not codegen support).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146786 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 11 insertions, 7 deletions

diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index 1b6b11a..d93108f 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -574,6 +574,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   if (Len == strlen(STR) && !memcmp(StartChar, STR, strlen(STR))) { \
     TyVal = LLVMTY; return lltok::Type; }
   TYPEKEYWORD("void",      Type::getVoidTy(Context));
+  TYPEKEYWORD("half",      Type::getHalfTy(Context));
   TYPEKEYWORD("float",     Type::getFloatTy(Context));
   TYPEKEYWORD("double",    Type::getDoubleTy(Context));
   TYPEKEYWORD("x86_fp80",  Type::getX86_FP80Ty(Context));
@@ -693,7 +694,7 @@ lltok::Kind LLLexer::Lex0x() {
   if (Kind == 'J') {
     // HexFPConstant - Floating point constant represented in IEEE format as a
     // hexadecimal number for when exponential notation is not precise enough.
-    // Float and double only.
+    // Half, Float, and double only.
     APFloatVal = APFloat(BitsToDouble(HexIntToVal(TokStart+2, CurPtr)));
     return lltok::APFloat;
   }
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 4678269..bccca4f 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -2483,13 +2483,16 @@ bool LLParser::ConvertValIDToValue(Type *Ty, ValID &ID, Value *&V,
         !ConstantFP::isValueValidForType(Ty, ID.APFloatVal))
       return Error(ID.Loc, "floating point constant invalid for type");
 
-    // The lexer has no type info, so builds all float and double FP constants
-    // as double.  Fix this here.  Long double does not need this.
-    if (&ID.APFloatVal.getSemantics() == &APFloat::IEEEdouble &&
-        Ty->isFloatTy()) {
+    // The lexer has no type info, so builds all half, float, and double FP
+    // constants as double.  Fix this here.  Long double does not need this.
+    if (&ID.APFloatVal.getSemantics() == &APFloat::IEEEdouble) {
       bool Ignored;
-      ID.APFloatVal.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven,
-                            &Ignored);
+      if (Ty->isHalfTy())
+        ID.APFloatVal.convert(APFloat::IEEEhalf, APFloat::rmNearestTiesToEven,
+                              &Ignored);
+      else if (Ty->isFloatTy())
+        ID.APFloatVal.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven,
+                              &Ignored);
     }
     V = ConstantFP::get(Context, ID.APFloatVal);