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- ; 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
- }
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