Merging r325463:

(I had to re-generate the test and manually update to handle the r323922 MIR physical register sigil.

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r325463 | aemerson | 2018-02-18 18:10:49 +0100 (Sun, 18 Feb 2018) | 8 lines

[AArch64][GlobalISel] Fix an assert fail/miscompile when fp16 types are copied
to gpr register banks.

PR36345.

rdar://36478867

Differential Revision: https://reviews.llvm.org/D43310
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@325586 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/Target/AArch64/AArch64InstructionSelector.cpp b/lib/Target/AArch64/AArch64InstructionSelector.cpp
index d60a156666e..a5fe398e7ea 100644
--- a/lib/Target/AArch64/AArch64InstructionSelector.cpp
+++ b/lib/Target/AArch64/AArch64InstructionSelector.cpp
@@ -354,6 +354,31 @@ static bool selectCopy(MachineInstr &I, const TargetInstrInfo &TII,
     return false;
   }
 
+  if (!TargetRegisterInfo::isPhysicalRegister(SrcReg)) {
+    const RegClassOrRegBank &RegClassOrBank =
+      MRI.getRegClassOrRegBank(SrcReg);
+
+    const TargetRegisterClass *SrcRC =
+        RegClassOrBank.dyn_cast<const TargetRegisterClass *>();
+    const RegisterBank *RB = nullptr;
+    if (!SrcRC) {
+      RB = RegClassOrBank.get<const RegisterBank *>();
+      SrcRC = getRegClassForTypeOnBank(MRI.getType(SrcReg), *RB, RBI, true);
+    }
+    // Copies from fpr16 to gpr32 need to use SUBREG_TO_REG.
+    if (RC == &AArch64::GPR32allRegClass && SrcRC == &AArch64::FPR16RegClass) {
+      unsigned PromoteReg = MRI.createVirtualRegister(&AArch64::FPR32RegClass);
+      BuildMI(*I.getParent(), I, I.getDebugLoc(),
+              TII.get(AArch64::SUBREG_TO_REG))
+          .addDef(PromoteReg)
+          .addImm(0)
+          .addUse(SrcReg)
+          .addImm(AArch64::hsub);
+      MachineOperand &RegOp = I.getOperand(1);
+      RegOp.setReg(PromoteReg);
+    }
+  }
+
   // No need to constrain SrcReg. It will get constrained when
   // we hit another of its use or its defs.
   // Copies do not have constraints.