From b1692ad2c3e35a2d1f6c5ea0e121579445078ba6 Mon Sep 17 00:00:00 2001
From: Tim Northover <tnorthover@apple.com>
Date: Tue, 29 Jul 2014 09:56:38 +0000
Subject: [PATCH] ARM: fix @llvm.convert.from.fp16 on softfloat targets.

We need to make sure we use the softened version of all appropriate operands in
the libcall, or things go horribly wrong. This may entail actually executing a
1-stage softening.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214175 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp |  7 ++++++-
 test/CodeGen/ARM/fp16.ll                        | 13 +++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index 41f2b4be99d..bcda2b8de65 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -377,10 +377,15 @@ SDValue DAGTypeLegalizer::SoftenFloatRes_FP_EXTEND(SDNode *N) {
   // There's only a libcall for f16 -> f32, so proceed in two stages. Also, it's
   // entirely possible for both f16 and f32 to be legal, so use the fully
   // hard-float FP_EXTEND rather than FP16_TO_FP.
-  if (Op.getValueType() == MVT::f16 && N->getValueType(0) != MVT::f32)
+  if (Op.getValueType() == MVT::f16 && N->getValueType(0) != MVT::f32) {
     Op = DAG.getNode(ISD::FP_EXTEND, SDLoc(N), MVT::f32, Op);
+    if (getTypeAction(MVT::f32) == TargetLowering::TypeSoftenFloat)
+      SoftenFloatResult(Op.getNode(), 0);
+  }
 
   RTLIB::Libcall LC = RTLIB::getFPEXT(Op.getValueType(), N->getValueType(0));
+  if (getTypeAction(Op.getValueType()) == TargetLowering::TypeSoftenFloat)
+    Op = GetSoftenedFloat(Op);
   assert(LC != RTLIB::UNKNOWN_LIBCALL && "Unsupported FP_EXTEND!");
   return TLI.makeLibCall(DAG, LC, NVT, &Op, 1, false, SDLoc(N)).first;
 }
diff --git a/test/CodeGen/ARM/fp16.ll b/test/CodeGen/ARM/fp16.ll
index d3f32556a09..501c2ba40ff 100644
--- a/test/CodeGen/ARM/fp16.ll
+++ b/test/CodeGen/ARM/fp16.ll
@@ -1,6 +1,8 @@
 ; RUN: llc < %s | FileCheck %s
 ; RUN: llc -mattr=+vfp3,+fp16 < %s | FileCheck --check-prefix=CHECK-FP16 %s
 ; RUN: llc -mtriple=armv8-eabi < %s | FileCheck --check-prefix=CHECK-ARMV8 %s
+; RUN: llc -mtriple=thumbv7m-eabi < %s | FileCheck --check-prefix=CHECK-SOFTFLOAT %s
+
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-n32"
 target triple = "armv7-eabi"
 
@@ -12,6 +14,7 @@ define arm_aapcs_vfpcc void @foo() nounwind {
 ; CHECK-LABEL: foo:
 ; CHECK-FP16-LABEL: foo:
 ; CHECK-ARMV8-LABEL: foo:
+; CHECK-SOFTFLOAT-LABEL: foo:
 entry:
   %0 = load i16* @x, align 2
   %1 = load i16* @y, align 2
@@ -19,15 +22,18 @@ entry:
 ; CHECK: __gnu_h2f_ieee
 ; CHECK-FP16: vcvtb.f32.f16
 ; CHECK-ARMv8: vcvtb.f32.f16
+; CHECK-SOFTFLOAT: __gnu_h2f_ieee
   %3 = tail call float @llvm.convert.from.fp16.f32(i16 %1)
 ; CHECK: __gnu_h2f_ieee
 ; CHECK-FP16: vcvtb.f32.f16
 ; CHECK-ARMV8: vcvtb.f32.f16
+; CHECK-SOFTFLOAT: __gnu_h2f_ieee
   %4 = fadd float %2, %3
   %5 = tail call i16 @llvm.convert.to.fp16.f32(float %4)
 ; CHECK: __gnu_f2h_ieee
 ; CHECK-FP16: vcvtb.f16.f32
 ; CHECK-ARMV8: vcvtb.f16.f32
+; CHECK-SOFTFLOAT: __gnu_f2h_ieee
   store i16 %5, i16* @x, align 2
   ret void
 }
@@ -36,6 +42,7 @@ define arm_aapcs_vfpcc double @test_from_fp16(i16 %in) {
 ; CHECK-LABEL: test_from_fp16:
 ; CHECK-FP-LABEL: test_from_fp16:
 ; CHECK-ARMV8-LABEL: test_from_fp16:
+; CHECK-SOFTFLOAT-LABEL: test_from_fp16:
   %val = call double @llvm.convert.from.fp16.f64(i16 %in)
 ; CHECK: bl __gnu_h2f_ieee
 ; CHECK: vmov [[TMP:s[0-9]+]], r0
@@ -47,6 +54,9 @@ define arm_aapcs_vfpcc double @test_from_fp16(i16 %in) {
 
 ; CHECK-ARMV8: vmov [[TMP:s[0-9]+]], r0
 ; CHECK-ARMV8: vcvtb.f64.f16 d0, [[TMP]]
+
+; CHECK-SOFTFLOAT: bl __gnu_h2f_ieee
+; CHECK-SOFTFLOAT: bl __aeabi_f2d
   ret double %val
 }
 
@@ -54,6 +64,7 @@ define arm_aapcs_vfpcc i16 @test_to_fp16(double %in) {
 ; CHECK-LABEL: test_to_fp16:
 ; CHECK-FP-LABEL: test_to_fp16:
 ; CHECK-ARMV8-LABEL: test_to_fp16:
+; CHECK-SOFTFLOAT-LABEL: test_to_fp16:
   %val = call i16 @llvm.convert.to.fp16.f64(double %in)
 ; CHECK: bl __truncdfhf2
 
@@ -61,6 +72,8 @@ define arm_aapcs_vfpcc i16 @test_to_fp16(double %in) {
 
 ; CHECK-ARMV8: vcvtb.f16.f64 [[TMP:s[0-9]+]], d0
 ; CHECK-ARMV8: vmov r0, [[TMP]]
+
+; CHECK-SOFTFLOAT: bl __truncdfhf2
   ret i16 %val
 }
 
-- 
2.40.0