add a note with a testcase

llvm-svn: 26877

llvm/lib/Target/X86/README.txt

@@ -633,3 +633,14 @@ dependent LICM pass or 2) makeing SelectDAG represent the whole function.
 The following tests perform worse with LSR:
 
 lambda, siod, optimizer-eval, ackermann, hash2, nestedloop, strcat, and Treesor.
+
+//===---------------------------------------------------------------------===//
+
+Should generate min/max for stuff like:
+
+void minf(float a, float b, float *X) {
+  *X = a <= b ? a : b;
+}
+
+//===---------------------------------------------------------------------===//
+