Add implicit def of EFLAGS on those instructions that may modify flags.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41962 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrFPStack.td b/lib/Target/X86/X86InstrFPStack.td
index d47add6..c4a4e4c 100644
--- a/lib/Target/X86/X86InstrFPStack.td
+++ b/lib/Target/X86/X86InstrFPStack.td
@@ -488,7 +488,7 @@
 def UCOM_FpIr80: FpI_<(outs), (ins RFP80:$lhs, RFP80:$rhs), CompareFP,
                   [(X86cmp RFP80:$lhs, RFP80:$rhs)]>; // CC = ST(0) cmp ST(i)
 
-let Uses = [ST0] in {
+let Defs = [EFLAGS], Uses = [ST0] in {
 def UCOM_Fr    : FPI<0xE0, AddRegFrm,    // FPSW = cmp ST(0) with ST(i)
                     (outs), (ins RST:$reg),
                     "fucom\t$reg">, DD;