SimplifyCFG: Expose phi node folding cost threshold as command line parameter

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130528 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 34 insertions, 0 deletions

diff --git a/test/Transforms/SimplifyCFG/PhiEliminate3.ll b/test/Transforms/SimplifyCFG/PhiEliminate3.ll
new file mode 100644
index 0000000000..3566b874c0
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/PhiEliminate3.ll
@@ -0,0 +1,34 @@
+; Test merging of blocks containing complex expressions,
+; with various folding thresholds
+;
+; RUN: opt < %s -simplifycfg -S -phi-node-folding-threshold=1 | grep N:
+; RUN: opt < %s -simplifycfg -S -phi-node-folding-threshold=2 | not grep N:
+; RUN: opt < %s -simplifycfg -S -phi-node-folding-threshold=2 | grep M:
+; RUN: opt < %s -simplifycfg -S -phi-node-folding-threshold=7 | not grep M:
+;
+
+define i32 @test(i1 %a, i1 %b, i32 %i, i32 %j, i32 %k) {
+entry:
+        br i1 %a, label %M, label %O
+O:
+        br i1 %b, label %P, label %Q
+P:
+        %iaj = add i32 %i, %j
+        %iajak = add i32 %iaj, %k
+        br label %N
+Q:
+        %ixj = xor i32 %i, %j
+        %ixjxk = xor i32 %ixj, %k
+        br label %N
+N:
+        ; This phi should be foldable if threshold >= 2
+        %Wp = phi i32 [ %iajak, %P ], [ %ixjxk, %Q ]
+        %Wp2 = add i32 %Wp, %Wp
+        br label %M
+M:
+        ; This phi should be foldable if threshold >= 7
+        %W = phi i32 [ %Wp2, %N ], [ 2, %entry ]
+        %R = add i32 %W, 1
+        ret i32 %R
+}
+