New testcase, allow folding of binary operators that use PHI nodes, as long

as the result of the binary operator is always constant.  This does not require
the PHI itself to be constant though.

llvm-svn: 10762

llvm/test/Regression/Transforms/SCCP/phitest.ll

@@ -0,0 +1,23 @@
+; RUN: llvm-as < %s | opt -sccp -dce -simplifycfg | llvm-dis | not grep br
+
+int %test(int %param) {
+entry:
+	%tmp.1 = setne int %param, 0
+	br bool %tmp.1, label %endif.0, label %else
+
+else:
+	br label %endif.0
+
+endif.0:
+	%a.0 = phi int [ 2, %else ], [ 3, %entry ]
+	%b.0 = phi int [ 3, %else ], [ 2, %entry ]
+	%tmp.5 = add int %a.0, %b.0
+	%tmp.7 = setne int %tmp.5, 5
+	br bool %tmp.7, label %UnifiedReturnBlock, label %endif.1
+
+endif.1:
+	ret int 0
+
+UnifiedReturnBlock:
+	ret int 2
+}