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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
}
|
