From 126f155f7f38df81ca81a67bcd7f07f8d7886615 Mon Sep 17 00:00:00 2001
From: Diana Picus <diana.picus@linaro.org>
Date: Thu, 16 Feb 2017 12:19:52 +0000
Subject: [PATCH] [ARM] GlobalISel: Select double G_FADD and copies

Just use VADDD if available, bail out if not.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295309 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMInstructionSelector.cpp          | 35 ++++++++++++++++++----
 .../ARM/GlobalISel/arm-instruction-select.mir      | 34 +++++++++++++++++++++
 2 files changed, 63 insertions(+), 6 deletions(-)

diff --git a/lib/Target/ARM/ARMInstructionSelector.cpp b/lib/Target/ARM/ARMInstructionSelector.cpp
index dcdd0e83550..5201ddba781 100644
--- a/lib/Target/ARM/ARMInstructionSelector.cpp
+++ b/lib/Target/ARM/ARMInstructionSelector.cpp
@@ -61,8 +61,12 @@ static bool selectCopy(MachineInstr &I, const TargetInstrInfo &TII,
   const TargetRegisterClass *RC = &ARM::GPRRegClass;
 
   if (RegBank->getID() == ARM::FPRRegBankID) {
-    assert(DstSize == 32 && "Only 32-bit FP values are supported");
-    RC = &ARM::SPRRegClass;
+    if (DstSize == 32)
+      RC = &ARM::SPRRegClass;
+    else if (DstSize == 64)
+      RC = &ARM::DPRRegClass;
+    else
+      llvm_unreachable("Unsupported destination size");
   }
 
   // No need to constrain SrcReg. It will get constrained when
@@ -76,6 +80,28 @@ static bool selectCopy(MachineInstr &I, const TargetInstrInfo &TII,
   return true;
 }
 
+static bool selectFAdd(MachineInstrBuilder &MIB, const ARMBaseInstrInfo &TII,
+                       MachineRegisterInfo &MRI) {
+  assert(TII.getSubtarget().hasVFP2() && "Can't select fp add without vfp");
+
+  LLT Ty = MRI.getType(MIB->getOperand(0).getReg());
+  unsigned ValSize = Ty.getSizeInBits();
+
+  if (ValSize == 32) {
+    if (TII.getSubtarget().useNEONForSinglePrecisionFP())
+      return false;
+    MIB->setDesc(TII.get(ARM::VADDS));
+  } else {
+    assert(ValSize == 64 && "Unsupported size for floating point value");
+    if (TII.getSubtarget().isFPOnlySP())
+      return false;
+    MIB->setDesc(TII.get(ARM::VADDD));
+  }
+  MIB.add(predOps(ARMCC::AL));
+
+  return true;
+}
+
 /// Select the opcode for simple extensions (that translate to a single SXT/UXT
 /// instruction). Extension operations more complicated than that should not
 /// invoke this.
@@ -186,11 +212,8 @@ bool ARMInstructionSelector::select(MachineInstr &I) const {
     MIB.add(predOps(ARMCC::AL)).add(condCodeOp());
     break;
   case G_FADD:
-    if (!TII.getSubtarget().hasVFP2() ||
-        TII.getSubtarget().useNEONForSinglePrecisionFP())
+    if (!selectFAdd(MIB, TII, MRI))
       return false;
-    I.setDesc(TII.get(ARM::VADDS));
-    MIB.add(predOps(ARMCC::AL));
     break;
   case G_FRAME_INDEX:
     // Add 0 to the given frame index and hope it will eventually be folded into
diff --git a/test/CodeGen/ARM/GlobalISel/arm-instruction-select.mir b/test/CodeGen/ARM/GlobalISel/arm-instruction-select.mir
index 48d58d71eb6..659c52c338d 100644
--- a/test/CodeGen/ARM/GlobalISel/arm-instruction-select.mir
+++ b/test/CodeGen/ARM/GlobalISel/arm-instruction-select.mir
@@ -10,6 +10,7 @@
   define void @test_add_s32() { ret void }
 
   define void @test_fadd_s32() #0 { ret void }
+  define void @test_fadd_s64() #0 { ret void }
 
   define void @test_load_from_stack() { ret void }
 
@@ -254,6 +255,39 @@ body:             |
     ; CHECK: BX_RET 14, _, implicit %s0
 ...
 ---
+name:            test_fadd_s64
+# CHECK-LABEL: name: test_fadd_s64
+legalized:       true
+regBankSelected: true
+selected:        false
+# CHECK: selected: true
+registers:
+  - { id: 0, class: fprb }
+  - { id: 1, class: fprb }
+  - { id: 2, class: fprb }
+# CHECK: id: 0, class: dpr
+# CHECK: id: 1, class: dpr
+# CHECK: id: 2, class: dpr
+body:             |
+  bb.0:
+    liveins: %d0, %d1
+
+    %0(s64) = COPY %d0
+    ; CHECK: [[VREGX:%[0-9]+]] = COPY %d0
+
+    %1(s64) = COPY %d1
+    ; CHECK: [[VREGY:%[0-9]+]] = COPY %d1
+
+    %2(s64) = G_FADD %0, %1
+    ; CHECK: [[VREGSUM:%[0-9]+]] = VADDD [[VREGX]], [[VREGY]], 14, _
+
+    %d0 = COPY %2(s64)
+    ; CHECK: %d0 = COPY [[VREGSUM]]
+
+    BX_RET 14, _, implicit %d0
+    ; CHECK: BX_RET 14, _, implicit %d0
+...
+---
 name:            test_load_from_stack
 # CHECK-LABEL: name: test_load_from_stack
 legalized:       true
-- 
2.11.0