New testcases for LICM improvement: code sinking.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10339 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/LICM/sink_inst.ll

@@ -0,0 +1,18 @@
+; If the result of an instruction is only used outside of the loop, sink
+; the instruction to the exit blocks instead of executing it on every
+; iteration of the loop.
+;
+; RUN: llvm-as < %s | opt -licm | llvm-dis | grep -C1 mul | grep Out: 
+
+int %test(int %N) {
+Entry:
+	br label %Loop
+Loop:
+        %N_addr.0.pn = phi int [ %dec, %Loop ], [ %N, %Entry ]
+        %tmp.6 = mul int %N, %N_addr.0.pn
+        %dec = add int %N_addr.0.pn, -1
+        %tmp.1 = setne int %N_addr.0.pn, 1
+        br bool %tmp.1, label %Loop, label %Out
+Out:
+	ret int %tmp.6
+}

test/Transforms/LICM/sink_load.ll

@@ -0,0 +1,20 @@
+; To reduce register pressure, if a load is hoistable out of the loop, and the
+; result of the load is only used outside of the loop, sink the load instead of
+; hoisting it!
+;
+; RUN: llvm-as < %s | opt -licm | llvm-dis | grep -C1 load | grep Out: 
+
+%X = global int 5
+
+int %test(int %N) {
+Entry:
+	br label %Loop
+Loop:
+        %N_addr.0.pn = phi int [ %dec, %Loop ], [ %N, %Entry ]
+        %tmp.6 = load int* %X
+        %dec = add int %N_addr.0.pn, -1
+        %tmp.1 = setne int %N_addr.0.pn, 1
+        br bool %tmp.1, label %Loop, label %Out
+Out:
+	ret int %tmp.6
+}

test/Transforms/LICM/sink_trapping_inst.ll

@@ -0,0 +1,17 @@
+; Potentially trapping instructions may be sunk as long as they are guaranteed
+; to be executed.
+;
+; RUN: llvm-as < %s | opt -licm | llvm-dis | grep -C1 div | grep Out: 
+
+int %test(int %N) {
+Entry:
+	br label %Loop
+Loop:
+        %N_addr.0.pn = phi int [ %dec, %Loop ], [ %N, %Entry ]
+        %tmp.6 = div int %N, %N_addr.0.pn
+        %dec = add int %N_addr.0.pn, -1
+        %tmp.1 = setne int %N_addr.0.pn, 0
+        br bool %tmp.1, label %Loop, label %Out
+Out:
+	ret int %tmp.6
+}