250 lines
6.5 KiB
LLVM
250 lines
6.5 KiB
LLVM
; RUN: opt < %s -basicaa -licm -S | FileCheck %s
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declare i32 @strlen(i8*) readonly
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declare void @foo()
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; Sink readonly function.
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define i32 @test1(i8* %P) {
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br label %Loop
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Loop: ; preds = %Loop, %0
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%A = call i32 @strlen( i8* %P ) readonly
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br i1 false, label %Loop, label %Out
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Out: ; preds = %Loop
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ret i32 %A
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; CHECK: @test1
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; CHECK: Out:
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; CHECK-NEXT: call i32 @strlen
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; CHECK-NEXT: ret i32 %A
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}
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declare double @sin(double) readnone
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; Sink readnone function out of loop with unknown memory behavior.
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define double @test2(double %X) {
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br label %Loop
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Loop: ; preds = %Loop, %0
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call void @foo( )
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%A = call double @sin( double %X ) readnone
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br i1 true, label %Loop, label %Out
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Out: ; preds = %Loop
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ret double %A
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; CHECK: @test2
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; CHECK: Out:
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; CHECK-NEXT: call double @sin
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; CHECK-NEXT: ret double %A
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}
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; This testcase checks to make sure the sinker does not cause problems with
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; critical edges.
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define void @test3() {
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Entry:
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br i1 false, label %Loop, label %Exit
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Loop:
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%X = add i32 0, 1
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br i1 false, label %Loop, label %Exit
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Exit:
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%Y = phi i32 [ 0, %Entry ], [ %X, %Loop ]
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ret void
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; CHECK: @test3
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; CHECK: Exit.loopexit:
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; CHECK-NEXT: %X = add i32 0, 1
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; CHECK-NEXT: br label %Exit
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}
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; If the result of an instruction is only used outside of the loop, sink
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; the instruction to the exit blocks instead of executing it on every
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; iteration of the loop.
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;
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define i32 @test4(i32 %N) {
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Entry:
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br label %Loop
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Loop: ; preds = %Loop, %Entry
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%N_addr.0.pn = phi i32 [ %dec, %Loop ], [ %N, %Entry ]
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%tmp.6 = mul i32 %N, %N_addr.0.pn ; <i32> [#uses=1]
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%tmp.7 = sub i32 %tmp.6, %N ; <i32> [#uses=1]
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%dec = add i32 %N_addr.0.pn, -1 ; <i32> [#uses=1]
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%tmp.1 = icmp ne i32 %N_addr.0.pn, 1 ; <i1> [#uses=1]
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br i1 %tmp.1, label %Loop, label %Out
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Out: ; preds = %Loop
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ret i32 %tmp.7
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; CHECK: @test4
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; CHECK: Out:
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; CHECK-NEXT: mul i32 %N, %N_addr.0.pn
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; CHECK-NEXT: sub i32 %tmp.6, %N
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; CHECK-NEXT: ret i32
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}
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; To reduce register pressure, if a load is hoistable out of the loop, and the
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; result of the load is only used outside of the loop, sink the load instead of
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; hoisting it!
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;
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@X = global i32 5 ; <i32*> [#uses=1]
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define i32 @test5(i32 %N) {
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Entry:
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br label %Loop
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Loop: ; preds = %Loop, %Entry
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%N_addr.0.pn = phi i32 [ %dec, %Loop ], [ %N, %Entry ]
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%tmp.6 = load i32* @X ; <i32> [#uses=1]
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%dec = add i32 %N_addr.0.pn, -1 ; <i32> [#uses=1]
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%tmp.1 = icmp ne i32 %N_addr.0.pn, 1 ; <i1> [#uses=1]
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br i1 %tmp.1, label %Loop, label %Out
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Out: ; preds = %Loop
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ret i32 %tmp.6
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; CHECK: @test5
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; CHECK: Out:
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; CHECK-NEXT: %tmp.6 = load i32* @X
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; CHECK-NEXT: ret i32 %tmp.6
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}
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; The loop sinker was running from the bottom of the loop to the top, causing
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; it to miss opportunities to sink instructions that depended on sinking other
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; instructions from the loop. Instead they got hoisted, which is better than
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; leaving them in the loop, but increases register pressure pointlessly.
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%Ty = type { i32, i32 }
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@X2 = external global %Ty
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define i32 @test6() {
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br label %Loop
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Loop:
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%dead = getelementptr %Ty* @X2, i64 0, i32 0
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%sunk2 = load i32* %dead
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br i1 false, label %Loop, label %Out
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Out: ; preds = %Loop
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ret i32 %sunk2
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; CHECK: @test6
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; CHECK: Out:
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; CHECK-NEXT: %dead = getelementptr %Ty* @X2, i64 0, i32 0
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; CHECK-NEXT: %sunk2 = load i32* %dead
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; CHECK-NEXT: ret i32 %sunk2
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}
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; This testcase ensures that we can sink instructions from loops with
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; multiple exits.
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;
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define i32 @test7(i32 %N, i1 %C) {
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Entry:
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br label %Loop
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Loop: ; preds = %ContLoop, %Entry
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%N_addr.0.pn = phi i32 [ %dec, %ContLoop ], [ %N, %Entry ]
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%tmp.6 = mul i32 %N, %N_addr.0.pn
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%tmp.7 = sub i32 %tmp.6, %N ; <i32> [#uses=2]
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%dec = add i32 %N_addr.0.pn, -1 ; <i32> [#uses=1]
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br i1 %C, label %ContLoop, label %Out1
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ContLoop:
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%tmp.1 = icmp ne i32 %N_addr.0.pn, 1
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br i1 %tmp.1, label %Loop, label %Out2
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Out1: ; preds = %Loop
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ret i32 %tmp.7
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Out2: ; preds = %ContLoop
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ret i32 %tmp.7
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; CHECK: @test7
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; CHECK: Out1:
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; CHECK-NEXT: mul i32 %N, %N_addr.0.pn
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; CHECK-NEXT: sub i32 %tmp.6, %N
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; CHECK-NEXT: ret
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; CHECK: Out2:
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; CHECK-NEXT: mul i32 %N, %N_addr.0.pn
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; CHECK-NEXT: sub i32 %tmp.6
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; CHECK-NEXT: ret
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}
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; This testcase checks to make sure we can sink values which are only live on
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; some exits out of the loop, and that we can do so without breaking dominator
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; info.
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define i32 @test8(i1 %C1, i1 %C2, i32* %P, i32* %Q) {
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Entry:
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br label %Loop
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Loop: ; preds = %Cont, %Entry
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br i1 %C1, label %Cont, label %exit1
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Cont: ; preds = %Loop
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%X = load i32* %P ; <i32> [#uses=2]
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store i32 %X, i32* %Q
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%V = add i32 %X, 1 ; <i32> [#uses=1]
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br i1 %C2, label %Loop, label %exit2
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exit1: ; preds = %Loop
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ret i32 0
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exit2: ; preds = %Cont
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ret i32 %V
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; CHECK: @test8
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; CHECK: exit1:
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; CHECK-NEXT: ret i32 0
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; CHECK: exit2:
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; CHECK-NEXT: %V = add i32 %X, 1
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; CHECK-NEXT: ret i32 %V
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}
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define void @test9() {
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loopentry.2.i:
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br i1 false, label %no_exit.1.i.preheader, label %loopentry.3.i.preheader
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no_exit.1.i.preheader: ; preds = %loopentry.2.i
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br label %no_exit.1.i
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no_exit.1.i: ; preds = %endif.8.i, %no_exit.1.i.preheader
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br i1 false, label %return.i, label %endif.8.i
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endif.8.i: ; preds = %no_exit.1.i
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%inc.1.i = add i32 0, 1 ; <i32> [#uses=1]
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br i1 false, label %no_exit.1.i, label %loopentry.3.i.preheader.loopexit
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loopentry.3.i.preheader.loopexit: ; preds = %endif.8.i
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br label %loopentry.3.i.preheader
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loopentry.3.i.preheader: ; preds = %loopentry.3.i.preheader.loopexit, %loopentry.2.i
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%arg_num.0.i.ph13000 = phi i32 [ 0, %loopentry.2.i ], [ %inc.1.i, %loopentry.3.i.preheader.loopexit ] ; <i32> [#uses=0]
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ret void
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return.i: ; preds = %no_exit.1.i
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ret void
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; CHECK: @test9
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; CHECK: loopentry.3.i.preheader.loopexit:
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; CHECK-NEXT: %inc.1.i = add i32 0, 1
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; CHECK-NEXT: br label %loopentry.3.i.preheader
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}
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; Potentially trapping instructions may be sunk as long as they are guaranteed
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; to be executed.
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define i32 @test10(i32 %N) {
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Entry:
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br label %Loop
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Loop: ; preds = %Loop, %Entry
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%N_addr.0.pn = phi i32 [ %dec, %Loop ], [ %N, %Entry ] ; <i32> [#uses=3]
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%tmp.6 = sdiv i32 %N, %N_addr.0.pn ; <i32> [#uses=1]
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%dec = add i32 %N_addr.0.pn, -1 ; <i32> [#uses=1]
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%tmp.1 = icmp ne i32 %N_addr.0.pn, 0 ; <i1> [#uses=1]
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br i1 %tmp.1, label %Loop, label %Out
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Out: ; preds = %Loop
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ret i32 %tmp.6
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; CHECK: @test10
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; CHECK: Out:
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; CHECK-NEXT: %tmp.6 = sdiv i32 %N, %N_addr.0.pn
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; CHECK-NEXT: ret i32 %tmp.6
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}
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; Should delete, not sink, dead instructions.
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define void @test11() {
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br label %Loop
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Loop:
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%dead = getelementptr %Ty* @X2, i64 0, i32 0
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br i1 false, label %Loop, label %Out
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Out:
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ret void
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; CHECK: @test11
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; CHECK: Out:
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; CHECK-NEXT: ret void
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}
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