From: Tim Northover <tnorthover@apple.com>
Date: Thu, 17 Jul 2014 11:04:04 +0000 (+0000)
Subject: X86: support double extension of f16 type.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ed05086d61a6ef6c375d9d7e7e7f5a94b03a5b58;p=oota-llvm.git

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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213251 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 39186c54f9d..d3d2c76de21 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -523,6 +523,10 @@ void X86TargetLowering::resetOperationActions() {
     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 {
diff --git a/test/CodeGen/X86/cvt16.ll b/test/CodeGen/X86/cvt16.ll
index f3d80493210..501145ca715 100644
--- a/test/CodeGen/X86/cvt16.ll
+++ b/test/CodeGen/X86/cvt16.ll
@@ -59,6 +59,20 @@ define float @test3(float %src) nounwind uwtable readnone {
 ; 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