Constrain both operands on MOVZX32_NOREXrr8.

[oota-llvm.git] / lib / Target / X86 / X86InstrInfo.cpp

diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index bad978d874711f07e3fd4957c905f936450161fb..86fb3a52724e932ad01c7b7f45ffc726a3813d60 100644 (file)
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -2189,9 +2189,12 @@ void X86InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
     // Copying to or from a physical H register on x86-64 requires a NOREX
     // move.  Otherwise use a normal move.
     if ((isHReg(DestReg) || isHReg(SrcReg)) &&
-        TM.getSubtarget<X86Subtarget>().is64Bit())
+        TM.getSubtarget<X86Subtarget>().is64Bit()) {
       Opc = X86::MOV8rr_NOREX;
-    else
+      // Both operands must be encodable without an REX prefix.
+      assert(X86::GR8_NOREXRegClass.contains(SrcReg, DestReg) &&
+             "8-bit H register can not be copied outside GR8_NOREX");
+    } else
       Opc = X86::MOV8rr;
   } else if (X86::VR128RegClass.contains(DestReg, SrcReg))
     Opc = HasAVX ? X86::VMOVAPSrr : X86::MOVAPSrr;