llvm-6502/test/Transforms/SimplifyCFG/indirectbr.ll
Bill Wendling 6a648b8538 If the block that we're threading through is jumped to by an indirect branch,
then we don't want to set the destination in the indirect branch to the
destination. This is because the indirect branch needs its destinations to have
had their block addresses taken. This isn't so of the new critical edge that's
split during this process. If it turns out that the destination block has only
one predecessor, and that being a BB with an indirect branch, then it won't be
marked as 'used' and may be removed.
PR10072


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132638 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-04 09:42:04 +00:00

252 lines
7.1 KiB
LLVM

; RUN: opt -S -simplifycfg < %s | FileCheck %s
; SimplifyCFG should eliminate redundant indirectbr edges.
; CHECK: indbrtest0
; CHECK: indirectbr i8* %t, [label %BB0, label %BB1, label %BB2]
; CHECK: %x = phi i32 [ 0, %BB0 ], [ 1, %entry ]
declare void @foo()
declare void @A()
declare void @B(i32)
declare void @C()
define void @indbrtest0(i8** %P, i8** %Q) {
entry:
store i8* blockaddress(@indbrtest0, %BB0), i8** %P
store i8* blockaddress(@indbrtest0, %BB1), i8** %P
store i8* blockaddress(@indbrtest0, %BB2), i8** %P
call void @foo()
%t = load i8** %Q
indirectbr i8* %t, [label %BB0, label %BB1, label %BB2, label %BB0, label %BB1, label %BB2]
BB0:
call void @A()
br label %BB1
BB1:
%x = phi i32 [ 0, %BB0 ], [ 1, %entry ], [ 1, %entry ]
call void @B(i32 %x)
ret void
BB2:
call void @C()
ret void
}
; SimplifyCFG should convert the indirectbr into a directbr. It would be even
; better if it removed the branch altogether, but simplifycfdg currently misses
; that because the predecessor is the entry block.
; CHECK: indbrtest1
; CHECK: br label %BB0
define void @indbrtest1(i8** %P, i8** %Q) {
entry:
store i8* blockaddress(@indbrtest1, %BB0), i8** %P
call void @foo()
%t = load i8** %Q
indirectbr i8* %t, [label %BB0, label %BB0]
BB0:
call void @A()
ret void
}
; SimplifyCFG should notice that BB0 does not have its address taken and
; remove it from entry's successor list.
; CHECK: indbrtest2
; CHECK: entry:
; CHECK-NEXT: unreachable
define void @indbrtest2(i8* %t) {
entry:
indirectbr i8* %t, [label %BB0, label %BB0]
BB0:
ret void
}
; Make sure the blocks in the next few tests aren't trivially removable as
; successors by taking their addresses.
@anchor = constant [13 x i8*] [
i8* blockaddress(@indbrtest3, %L1), i8* blockaddress(@indbrtest3, %L2), i8* blockaddress(@indbrtest3, %L3),
i8* blockaddress(@indbrtest4, %L1), i8* blockaddress(@indbrtest4, %L2), i8* blockaddress(@indbrtest4, %L3),
i8* blockaddress(@indbrtest5, %L1), i8* blockaddress(@indbrtest5, %L2), i8* blockaddress(@indbrtest5, %L3), i8* blockaddress(@indbrtest5, %L4),
i8* blockaddress(@indbrtest6, %L1), i8* blockaddress(@indbrtest6, %L2), i8* blockaddress(@indbrtest6, %L3)
]
; SimplifyCFG should turn the indirectbr into a conditional branch on the
; condition of the select.
; CHECK: @indbrtest3
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 %cond, label %L1, label %L2
; CHECK-NOT: indirectbr
; CHECK-NOT: br
; CHECK-NOT: L3:
define void @indbrtest3(i1 %cond, i8* %address) nounwind {
entry:
%indirect.goto.dest = select i1 %cond, i8* blockaddress(@indbrtest3, %L1), i8* blockaddress(@indbrtest3, %L2)
indirectbr i8* %indirect.goto.dest, [label %L1, label %L2, label %L3]
L1:
call void @A()
ret void
L2:
call void @C()
ret void
L3:
call void @foo()
ret void
}
; SimplifyCFG should turn the indirectbr into an unconditional branch to the
; only possible destination.
; As in @indbrtest1, it should really remove the branch entirely, but it doesn't
; because it's in the entry block.
; CHECK: @indbrtest4
; CHECK-NEXT: entry:
; CHECK-NEXT: br label %L1
define void @indbrtest4(i1 %cond) nounwind {
entry:
%indirect.goto.dest = select i1 %cond, i8* blockaddress(@indbrtest4, %L1), i8* blockaddress(@indbrtest4, %L1)
indirectbr i8* %indirect.goto.dest, [label %L1, label %L2, label %L3]
L1:
call void @A()
ret void
L2:
call void @C()
ret void
L3:
call void @foo()
ret void
}
; SimplifyCFG should turn the indirectbr into an unreachable because neither
; destination is listed as a successor.
; CHECK: @indbrtest5
; CHECK-NEXT: entry:
; CHECK-NEXT: unreachable
; CHECK-NEXT: }
define void @indbrtest5(i1 %cond, i8* %anchor) nounwind {
entry:
%indirect.goto.dest = select i1 %cond, i8* blockaddress(@indbrtest5, %L1), i8* blockaddress(@indbrtest5, %L2)
; This needs to have more than one successor for this test, otherwise it gets
; replaced with an unconditional branch to the single successor.
indirectbr i8* %indirect.goto.dest, [label %L3, label %L4]
L1:
call void @A()
ret void
L2:
call void @C()
ret void
L3:
call void @foo()
ret void
L4:
call void @foo()
; This keeps blockaddresses not otherwise listed as successors from being zapped
; before SimplifyCFG even looks at the indirectbr.
indirectbr i8* %anchor, [label %L1, label %L2]
}
; The same as above, except the selected addresses are equal.
; CHECK: @indbrtest6
; CHECK-NEXT: entry:
; CHECK-NEXT: unreachable
; CHECK-NEXT: }
define void @indbrtest6(i1 %cond, i8* %anchor) nounwind {
entry:
%indirect.goto.dest = select i1 %cond, i8* blockaddress(@indbrtest6, %L1), i8* blockaddress(@indbrtest6, %L1)
; This needs to have more than one successor for this test, otherwise it gets
; replaced with an unconditional branch to the single successor.
indirectbr i8* %indirect.goto.dest, [label %L2, label %L3]
L1:
call void @A()
ret void
L2:
call void @C()
ret void
L3:
call void @foo()
; This keeps blockaddresses not otherwise listed as successors from being zapped
; before SimplifyCFG even looks at the indirectbr.
indirectbr i8* %anchor, [label %L1, label %L2]
}
; PR10072
@xblkx.bbs = internal unnamed_addr constant [9 x i8*] [i8* blockaddress(@indbrtest7, %xblkx.begin), i8* blockaddress(@indbrtest7, %xblkx.begin3), i8* blockaddress(@indbrtest7, %xblkx.begin4), i8* blockaddress(@indbrtest7, %xblkx.begin5), i8* blockaddress(@indbrtest7, %xblkx.begin6), i8* blockaddress(@indbrtest7, %xblkx.begin7), i8* blockaddress(@indbrtest7, %xblkx.begin8), i8* blockaddress(@indbrtest7, %xblkx.begin9), i8* blockaddress(@indbrtest7, %xblkx.end)]
define void @indbrtest7() {
escape-string.top:
%xval202x = call i32 @xfunc5x()
br label %xlab5x
xlab8x: ; preds = %xlab5x
%xvaluex = call i32 @xselectorx()
%xblkx.x = getelementptr [9 x i8*]* @xblkx.bbs, i32 0, i32 %xvaluex
%xblkx.load = load i8** %xblkx.x
indirectbr i8* %xblkx.load, [label %xblkx.begin, label %xblkx.begin3, label %xblkx.begin4, label %xblkx.begin5, label %xblkx.begin6, label %xblkx.begin7, label %xblkx.begin8, label %xblkx.begin9, label %xblkx.end]
xblkx.begin:
br label %xblkx.end
xblkx.begin3:
br label %xblkx.end
xblkx.begin4:
br label %xblkx.end
xblkx.begin5:
br label %xblkx.end
xblkx.begin6:
br label %xblkx.end
xblkx.begin7:
br label %xblkx.end
xblkx.begin8:
br label %xblkx.end
xblkx.begin9:
br label %xblkx.end
xblkx.end:
%yes.0 = phi i1 [ false, %xblkx.begin ], [ true, %xlab8x ], [ false, %xblkx.begin9 ], [ false, %xblkx.begin8 ], [ false, %xblkx.begin7 ], [ false, %xblkx.begin6 ], [ false, %xblkx.begin5 ], [ true, %xblkx.begin4 ], [ false, %xblkx.begin3 ]
br i1 %yes.0, label %v2j, label %xlab17x
v2j:
; CHECK: %xunusedx = call i32 @xactionx()
%xunusedx = call i32 @xactionx()
br label %xlab4x
xlab17x:
br label %xlab4x
xlab4x:
%incr19 = add i32 %xval704x.0, 1
br label %xlab5x
xlab5x:
%xval704x.0 = phi i32 [ 0, %escape-string.top ], [ %incr19, %xlab4x ]
%xval10x = icmp ult i32 %xval704x.0, %xval202x
br i1 %xval10x, label %xlab8x, label %xlab9x
xlab9x:
ret void
}
declare i32 @xfunc5x()
declare i8 @xfunc7x()
declare i32 @xselectorx()
declare i32 @xactionx()