CodeGen: soften f16 type by default instead of marking legal.

Actual support for softening f16 operations is still limited, and can be added
when it's needed.  But Soften is much closer to being a useful thing to try
than keeping it Legal when no registers can actually hold such values.

Longer term, we probably want something between Soften and Promote semantics
for most targets, it'll be more efficient to promote the 4 basic operations to
f32 than libcall them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213372 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetLowering.h

@@ -1635,7 +1635,7 @@ public:
       LegalizeTypeAction LA = ValueTypeActions.getTypeAction(SVT);
 
       assert(
-        (LA == TypeLegal ||
+        (LA == TypeLegal || LA == TypeSoftenFloat ||
          ValueTypeActions.getTypeAction(NVT) != TypePromoteInteger)
          && "Promote may not follow Expand or Promote");
 

lib/CodeGen/TargetLoweringBase.cpp

@@ -1104,6 +1104,13 @@ void TargetLoweringBase::computeRegisterProperties() {
     }
   }
 
+  if (!isTypeLegal(MVT::f16)) {
+    NumRegistersForVT[MVT::f16] = NumRegistersForVT[MVT::i16];
+    RegisterTypeForVT[MVT::f16] = RegisterTypeForVT[MVT::i16];
+    TransformToType[MVT::f16] = MVT::i16;
+    ValueTypeActions.setTypeAction(MVT::f16, TypeSoftenFloat);
+  }
+
   // Loop over all of the vector value types to see which need transformations.
   for (unsigned i = MVT::FIRST_VECTOR_VALUETYPE;
        i <= (unsigned)MVT::LAST_VECTOR_VALUETYPE; ++i) {

test/CodeGen/AArch64/half.ll

@@ -0,0 +1,26 @@
+; RUN: llc < %s -mtriple=arm64-apple-ios7.0 | FileCheck %s
+
+define void @test_load_store(half* %in, half* %out) {
+; CHECK-LABEL: test_load_store:
+; CHECK: ldr [[TMP:h[0-9]+]], [x0]
+; CHECK: str [[TMP]], [x1]
+  %val = load half* %in
+  store half %val, half* %out
+  ret void
+}
+
+define i16 @test_bitcast_from_half(half* %addr) {
+; CHECK-LABEL: test_bitcast_from_half:
+; CHECK: ldrh w0, [x0]
+  %val = load half* %addr
+  %val_int = bitcast half %val to i16
+  ret i16 %val_int
+}
+
+define void @test_bitcast_to_half(half* %addr, i16 %in) {
+; CHECK-LABEL: test_bitcast_to_half:
+; CHECK: strh w1, [x0]
+  %val_fp = bitcast i16 %in to half
+  store half %val_fp, half* %addr
+  ret void
+}

test/CodeGen/ARM/half.ll

@@ -0,0 +1,26 @@
+; RUN: llc < %s -mtriple=thumbv7s-apple-ios7.0 | FileCheck %s
+
+define void @test_load_store(half* %in, half* %out) {
+; CHECK-LABEL: test_load_store:
+; CHECK: ldrh [[TMP:r[0-9]+]], [r0]
+; CHECK: strh [[TMP]], [r1]
+  %val = load half* %in
+  store half %val, half* %out
+  ret void
+}
+
+define i16 @test_bitcast_from_half(half* %addr) {
+; CHECK-LABEL: test_bitcast_from_half:
+; CHECK: ldrh r0, [r0]
+  %val = load half* %addr
+  %val_int = bitcast half %val to i16
+  ret i16 %val_int
+}
+
+define void @test_bitcast_to_half(half* %addr, i16 %in) {
+; CHECK-LABEL: test_bitcast_to_half:
+; CHECK: strh r1, [r0]
+  %val_fp = bitcast i16 %in to half
+  store half %val_fp, half* %addr
+  ret void
+}

test/CodeGen/NVPTX/half.ll

@@ -0,0 +1,30 @@
+; RUN: llc < %s -march=nvptx | FileCheck %s
+
+define void @test_load_store(half addrspace(1)* %in, half addrspace(1)* %out) {
+; CHECK-LABEL: @test_load_store
+; CHECK: ld.global.u16 [[TMP:%rs[0-9]+]], [{{%r[0-9]+}}]
+; CHECK: st.global.u16 [{{%r[0-9]+}}], [[TMP]]
+  %val = load half addrspace(1)* %in
+  store half %val, half addrspace(1) * %out
+  ret void
+}
+
+define void @test_bitcast_from_half(half addrspace(1)* %in, i16 addrspace(1)* %out) {
+; CHECK-LABEL: @test_bitcast_from_half
+; CHECK: ld.global.u16 [[TMP:%rs[0-9]+]], [{{%r[0-9]+}}]
+; CHECK: st.global.u16 [{{%r[0-9]+}}], [[TMP]]
+  %val = load half addrspace(1) * %in
+  %val_int = bitcast half %val to i16
+  store i16 %val_int, i16 addrspace(1)* %out
+  ret void
+}
+
+define void @test_bitcast_to_half(half addrspace(1)* %out, i16 addrspace(1)* %in) {
+; CHECK-LABEL: @test_bitcast_to_half
+; CHECK: ld.global.u16 [[TMP:%rs[0-9]+]], [{{%r[0-9]+}}]
+; CHECK: st.global.u16 [{{%r[0-9]+}}], [[TMP]]
+  %val = load i16 addrspace(1)* %in
+  %val_fp = bitcast i16 %val to half
+  store half %val_fp, half addrspace(1)* %out
+  ret void
+}

test/CodeGen/R600/half.ll

@@ -0,0 +1,30 @@
+; RUN: llc < %s -march=r600 -mcpu=SI | FileCheck %s
+
+define void @test_load_store(half addrspace(1)* %in, half addrspace(1)* %out) {
+; CHECK-LABEL: @test_load_store
+; CHECK: BUFFER_LOAD_USHORT [[TMP:v[0-9]+]]
+; CHECK: BUFFER_STORE_SHORT [[TMP]]
+  %val = load half addrspace(1)* %in
+  store half %val, half addrspace(1) * %out
+  ret void
+}
+
+define void @test_bitcast_from_half(half addrspace(1)* %in, i16 addrspace(1)* %out) {
+; CHECK-LABEL: @test_bitcast_from_half
+; CHECK: BUFFER_LOAD_USHORT [[TMP:v[0-9]+]]
+; CHECK: BUFFER_STORE_SHORT [[TMP]]
+  %val = load half addrspace(1) * %in
+  %val_int = bitcast half %val to i16
+  store i16 %val_int, i16 addrspace(1)* %out
+  ret void
+}
+
+define void @test_bitcast_to_half(half addrspace(1)* %out, i16 addrspace(1)* %in) {
+; CHECK-LABEL: @test_bitcast_to_half
+; CHECK: BUFFER_LOAD_USHORT [[TMP:v[0-9]+]]
+; CHECK: BUFFER_STORE_SHORT [[TMP]]
+  %val = load i16 addrspace(1)* %in
+  %val_fp = bitcast i16 %val to half
+  store half %val_fp, half addrspace(1)* %out
+  ret void
+}

test/CodeGen/X86/half.ll

@@ -0,0 +1,27 @@
+; RUN: llc < %s -march=x86-64 -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 -mattr=-f16c | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-LIBCALL
+; RUN: llc < %s -march=x86-64 -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 -mattr=+f16c | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-F16C
+
+define void @test_load_store(half* %in, half* %out) {
+; CHECK-LABEL: test_load_store:
+; CHECK: movw (%rdi), [[TMP:%[a-z0-9]+]]
+; CHECK: movw [[TMP]], (%rsi)
+  %val = load half* %in
+  store half %val, half* %out
+  ret void
+}
+
+define i16 @test_bitcast_from_half(half* %addr) {
+; CHECK-LABEL: test_bitcast_from_half:
+; CHECK: movzwl (%rdi), %eax
+  %val = load half* %addr
+  %val_int = bitcast half %val to i16
+  ret i16 %val_int
+}
+
+define void @test_bitcast_to_half(half* %addr, i16 %in) {
+; CHECK-LABEL: test_bitcast_to_half:
+; CHECK: movw %si, (%rdi)
+  %val_fp = bitcast i16 %in to half
+  store half %val_fp, half* %addr
+  ret void
+}