1 files changed, 131 insertions, 0 deletions
diff --git a/test/Transforms/SimplifyCFG/2008-05-16-PHIBlockMerge.ll b/test/Transforms/SimplifyCFG/2008-05-16-PHIBlockMerge.ll
new file mode 100644
index 0000000..59e886b
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/2008-05-16-PHIBlockMerge.ll
@@ -0,0 +1,131 @@
+; RUN: opt < %s -simplifycfg -S > %t
+; RUN: not grep {^BB.tomerge} %t
+; RUN  grep {^BB.nomerge} %t | count 2
+
+; ModuleID = '<stdin>' 
+declare i1 @foo()
+
+declare i1 @bar(i32)
+
+; This function can't be merged
+define void @a() {
+entry:
+	br label %BB.nomerge
+
+BB.nomerge:		; preds = %Common, %entry
+        ; This phi has a conflicting value (0) with below phi (2), so blocks
+        ; can't be merged.
+	%a = phi i32 [ 1, %entry ], [ 0, %Common ]		; <i32> [#uses=1]
+	br label %Succ
+
+Succ:		; preds = %Common, %BB.nomerge
+	%b = phi i32 [ %a, %BB.nomerge ], [ 2, %Common ]		; <i32> [#uses=0]
+	%conde = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %conde, label %Common, label %Exit
+
+Common:		; preds = %Succ
+	%cond = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %cond, label %BB.nomerge, label %Succ
+
+Exit:		; preds = %Succ
+	ret void
+}
+
+; This function can't be merged
+define void @b() {
+entry:
+	br label %BB.nomerge
+
+BB.nomerge:		; preds = %Common, %entry
+	br label %Succ
+
+Succ:		; preds = %Common, %BB.nomerge
+        ; This phi has confliction values for Common and (through BB) Common,
+        ; blocks can't be merged
+	%b = phi i32 [ 1, %BB.nomerge ], [ 2, %Common ]		; <i32> [#uses=0]
+	%conde = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %conde, label %Common, label %Exit
+
+Common:		; preds = %Succ
+	%cond = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %cond, label %BB.nomerge, label %Succ
+
+Exit:		; preds = %Succ
+	ret void
+}
+
+; This function can be merged
+define void @c() {
+entry:
+	br label %BB.tomerge
+
+BB.tomerge:		; preds = %Common, %entry
+	br label %Succ
+
+Succ:		; preds = %Common, %BB.tomerge, %Pre-Exit
+        ; This phi has identical values for Common and (through BB) Common,
+        ; blocks can't be merged
+	%b = phi i32 [ 1, %BB.tomerge ], [ 1, %Common ], [ 2, %Pre-Exit ]
+	%conde = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %conde, label %Common, label %Pre-Exit
+
+Common:		; preds = %Succ
+	%cond = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %cond, label %BB.tomerge, label %Succ
+
+Pre-Exit:       ; preds = %Succ
+        ; This adds a backedge, so the %b phi node gets a third branch and is
+        ; not completely trivial
+	%cond2 = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %cond2, label %Succ, label %Exit
+        
+Exit:		; preds = %Pre-Exit
+	ret void
+}
+
+; This function can be merged
+define void @d() {
+entry:
+	br label %BB.tomerge
+
+BB.tomerge:		; preds = %Common, %entry
+        ; This phi has a matching value (0) with below phi (0), so blocks
+        ; can be merged.
+	%a = phi i32 [ 1, %entry ], [ 0, %Common ]		; <i32> [#uses=1]
+	br label %Succ
+
+Succ:		; preds = %Common, %BB.tomerge
+	%b = phi i32 [ %a, %BB.tomerge ], [ 0, %Common ]		; <i32> [#uses=0]
+	%conde = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %conde, label %Common, label %Exit
+
+Common:		; preds = %Succ
+	%cond = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %cond, label %BB.tomerge, label %Succ
+
+Exit:		; preds = %Succ
+	ret void
+}
+
+; This function can be merged
+define void @e() {
+entry:
+	br label %BB.tomerge
+
+BB.tomerge:		; preds = %Use, %entry
+        ; This phi is used somewhere else than Succ, but this should not prevent
+        ; merging this block
+	%a = phi i32 [ 1, %entry ], [ 0, %Use ]		; <i32> [#uses=1]
+	br label %Succ
+
+Succ:		; preds = %BB.tomerge
+	%conde = call i1 @foo( )		; <i1> [#uses=1]
+	br i1 %conde, label %Use, label %Exit
+
+Use:		; preds = %Succ
+	%cond = call i1 @bar( i32 %a )		; <i1> [#uses=1]
+	br i1 %cond, label %BB.tomerge, label %Exit
+
+Exit:		; preds = %Use, %Succ
+	ret void
+}