[llvm] r213251 - X86: support double extension of f16 type.

[Tim Northover]

Author: tnorthover
Date: Thu Jul 17 06:04:04 2014
New Revision: 213251

URL: http://llvm.org/viewvc/llvm-project?rev=213251&view=rev
Log:
X86: support double extension of f16 type.

x86 has no native ability to extend an f16 to f64, but the same result
is obtained if we expand it into two separate extensions: f16 -> f32
-> f64.

Unfortunately the same is not true for truncate, so that still results
in a compilation failure.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/test/CodeGen/X86/cvt16.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=213251&r1=213250&r2=213251&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Jul 17 06:04:04 2014
@@ -523,6 +523,10 @@ void X86TargetLowering::resetOperationAc
     setOperationAction(ISD::FP_TO_FP16, MVT::f32, Expand);
   }
 
+  // There's never any support for extending beyond MVT::f32.
+  setOperationAction(ISD::FP16_TO_FP, MVT::f64, Expand);
+  setOperationAction(ISD::FP16_TO_FP, MVT::f80, Expand);
+
   if (Subtarget->hasPOPCNT()) {
     setOperationAction(ISD::CTPOP          , MVT::i8   , Promote);
   } else {

Modified: llvm/trunk/test/CodeGen/X86/cvt16.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/cvt16.ll?rev=213251&r1=213250&r2=213251&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/cvt16.ll (original)
+++ llvm/trunk/test/CodeGen/X86/cvt16.ll Thu Jul 17 06:04:04 2014
@@ -59,6 +59,20 @@ define float @test3(float %src) nounwind
 ; F16C-NEXT: vcvtph2ps
 ; F16C: ret
 
+define double @test4(i16* nocapture %src) {
+  %1 = load i16* %src, align 2
+  %2 = tail call double @llvm.convert.from.fp16.f64(i16 %1)
+  ret double %2
+}
+; CHECK-LABEL: test4:
+; LIBCALL: callq  __gnu_h2f_ieee
+; LIBCALL: cvtss2sd
+; SOFTFLOAT: callq  __gnu_h2f_ieee
+; SOFTFLOAT: callq __extendsfdf2
+; F16C: vcvtph2ps
+; F16C: vcvtss2sd
+; F16C: ret
+
 declare float @llvm.convert.from.fp16.f32(i16) nounwind readnone
 declare i16 @llvm.convert.to.fp16.f32(float) nounwind readnone
-
+declare double @llvm.convert.from.fp16.f64(i16) nounwind readnone