[X86] Add test for PR63055 (NFC)

(cherry picked from commit 9694e0f)

Author: nikic

llvm/test/CodeGen/X86/setcc.ll

@@ -338,3 +338,20 @@ define i32 @PR55138(i32 %x) {
   %and = and i32 %shr, 1
   ret i32 %and
 }
+
+; FIXME: Miscompile.
+define i64 @pr63055(double %arg) {
+; X86-LABEL: pr63055:
+; X86:       ## %bb.0:
+; X86-NEXT:    movl $255, %eax
+; X86-NEXT:    xorl %edx, %edx
+; X86-NEXT:    retl
+;
+; X64-LABEL: pr63055:
+; X64:       ## %bb.0:
+; X64-NEXT:    movl $255, %eax
+; X64-NEXT:    retq
+  %fcmp = fcmp une double 0x7FF8000000000000, %arg
+  %ext = zext i1 %fcmp to i64
+  ret i64 %ext
+}