Be more precise.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40689 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 217f6d5..ab2c8dc 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -548,7 +548,7 @@
                // This probably ought to be moved to a def : Pat<> if the
                // syntax can be accepted.
                [(set AL, (mul AL, GR8:$src))]>,
-             Imp<[AL],[AX]>;               // AL,AH = AL*GR8
+             Imp<[AL],[AL,AH]>;               // AL,AH = AL*GR8
 def MUL16r : I<0xF7, MRM4r, (outs),  (ins GR16:$src), "mul{w}\t$src", []>,
              Imp<[AX],[AX,DX]>, OpSize;    // AX,DX = AX*GR16
 def MUL32r : I<0xF7, MRM4r, (outs),  (ins GR32:$src), "mul{l}\t$src", []>,