New testcase

llvm-svn: 10760

test/Regression/Transforms/ScalarRepl/phinodepromote.ll

@@ -0,0 +1,35 @@
+; RUN: llvm-as < %s | opt -mem2reg | llvm-dis | not grep alloca
+;
+; This tests to see if mem2reg can promote alloca instructions whose addresses
+; are used by PHI nodes that are immediately loaded.  The LLVM C++ front-end
+; often generates code that looks like this (when it codegen's ?: exprs as 
+; lvalues), so handling this simple extension is quite useful.
+;
+; This testcase is what the following program looks like when it reaches
+; mem2reg:
+;
+; template<typename T>
+; const T& max(const T& a1, const T& a2) { return a1 < a2 ? a1 : a2; }
+; int main() { return max(0, 1); }
+;
+
+int %main() {
+entry:
+        %mem_tmp.0 = alloca int
+        %mem_tmp.1 = alloca int
+        store int 0, int* %mem_tmp.0
+        store int 1, int* %mem_tmp.1
+        %tmp.1.i = load int* %mem_tmp.1
+        %tmp.3.i = load int* %mem_tmp.0
+        %tmp.4.i = setle int %tmp.1.i, %tmp.3.i
+        br bool %tmp.4.i, label %cond_true.i, label %cond_continue.i
+
+cond_true.i:
+        br label %cond_continue.i
+
+cond_continue.i:
+        %mem_tmp.i.0 = phi int* [ %mem_tmp.1, %cond_true.i ], [ %mem_tmp.0, %entry ]
+        %tmp.3 = load int* %mem_tmp.i.0
+        ret int %tmp.3
+}
+