ARM: allow vanilla expressions for movw/movt.

Expressions for movw/movt don't always have an :upper16: or :lower16:
on them and that's ok. When they don't, it's just a plain [0-65536]
immediate result, effectively the same as a :lower16: variant kind.

rdar://10550147

llvm-svn: 155941

1 files changed, 16 insertions, 4 deletions

diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
index 1589a5d2194..31f43fe11c9 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
@@ -861,11 +861,11 @@ ARMMCCodeEmitter::getHiLo16ImmOpValue(const MCInst &MI, unsigned OpIdx,
 
   // Handle :upper16: and :lower16: assembly prefixes.
   const MCExpr *E = MO.getExpr();
+  MCFixupKind Kind;
   if (E->getKind() == MCExpr::Target) {
     const ARMMCExpr *ARM16Expr = cast<ARMMCExpr>(E);
     E = ARM16Expr->getSubExpr();
 
-    MCFixupKind Kind;
     switch (ARM16Expr->getKind()) {
     default: llvm_unreachable("Unsupported ARMFixup");
     case ARMMCExpr::VK_ARM_HI16:
@@ -891,9 +891,21 @@ ARMMCCodeEmitter::getHiLo16ImmOpValue(const MCInst &MI, unsigned OpIdx,
     }
     Fixups.push_back(MCFixup::Create(0, E, Kind, MI.getLoc()));
     return 0;
-  };
-
-  llvm_unreachable("Unsupported MCExpr type in MCOperand!");
+  }
+  // If the expression doesn't have :upper16: or :lower16: on it,
+  // it's just a plain immediate expression, and those evaluate to
+  // the lower 16 bits of the expression regardless of whether
+  // we have a movt or a movw.
+  if (!isTargetDarwin() && EvaluateAsPCRel(E))
+    Kind = MCFixupKind(isThumb2()
+                       ? ARM::fixup_t2_movw_lo16_pcrel
+                       : ARM::fixup_arm_movw_lo16_pcrel);
+  else
+    Kind = MCFixupKind(isThumb2()
+                       ? ARM::fixup_t2_movw_lo16
+                       : ARM::fixup_arm_movw_lo16);
+  Fixups.push_back(MCFixup::Create(0, E, Kind, MI.getLoc()));
+  return 0;
 }
 
 uint32_t ARMMCCodeEmitter::