forked from OSchip/llvm-project
420 lines
13 KiB
LLVM
420 lines
13 KiB
LLVM
; RUN: opt < %s -analyze -block-freq | FileCheck %s
|
|
; RUN: opt < %s -passes='print<block-freq>' -disable-output 2>&1 | FileCheck %s
|
|
|
|
; A loop with multiple exits isn't irreducible. It should be handled
|
|
; correctly.
|
|
;
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'multiexit':
|
|
; CHECK-NEXT: block-frequency-info: multiexit
|
|
define void @multiexit(i1 %x) {
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
entry:
|
|
br label %loop.1
|
|
|
|
; CHECK-NEXT: loop.1: float = 2.0,
|
|
loop.1:
|
|
br i1 %x, label %exit.1, label %loop.2, !prof !0
|
|
|
|
; CHECK-NEXT: loop.2: float = 1.75,
|
|
loop.2:
|
|
br i1 %x, label %exit.2, label %loop.1, !prof !1
|
|
|
|
; CHECK-NEXT: exit.1: float = 0.25,
|
|
exit.1:
|
|
br label %return
|
|
|
|
; CHECK-NEXT: exit.2: float = 0.75,
|
|
exit.2:
|
|
br label %return
|
|
|
|
; CHECK-NEXT: return: float = 1.0, int = [[ENTRY]]
|
|
return:
|
|
ret void
|
|
}
|
|
|
|
!0 = !{!"branch_weights", i32 1, i32 7}
|
|
!1 = !{!"branch_weights", i32 3, i32 4}
|
|
|
|
; Irreducible control flow
|
|
; ========================
|
|
;
|
|
; LoopInfo defines a loop as a non-trivial SCC dominated by a single block,
|
|
; called the header. A given loop, L, can have sub-loops, which are loops
|
|
; within the subgraph of L that excludes the header.
|
|
;
|
|
; In addition to loops, -block-freq has limited support for irreducible SCCs,
|
|
; which are SCCs with multiple entry blocks. Irreducible SCCs are discovered
|
|
; on they fly, and modelled as loops with multiple headers.
|
|
;
|
|
; The headers of irreducible sub-SCCs consist of its entry blocks and all nodes
|
|
; that are targets of a backedge within it (excluding backedges within true
|
|
; sub-loops).
|
|
;
|
|
; -block-freq is currently designed to act like a block is inserted that
|
|
; intercepts all the edges to the headers. All backedges and entries point to
|
|
; this block. Its successors are the headers, which split the frequency
|
|
; evenly.
|
|
;
|
|
; There are a number of testcases below. Only the first two have detailed
|
|
; explanations.
|
|
;
|
|
; Testcase #1
|
|
; ===========
|
|
;
|
|
; In this case c1 and c2 should have frequencies of 15/7 and 13/7,
|
|
; respectively. To calculate this, consider assigning 1.0 to entry, and
|
|
; distributing frequency iteratively (to infinity). At the first iteration,
|
|
; entry gives 3/4 to c1 and 1/4 to c2. At every step after, c1 and c2 give 3/4
|
|
; of what they have to each other. Somehow, all of it comes out to exit.
|
|
;
|
|
; c1 = 3/4 + 1/4*3/4 + 3/4*3^2/4^2 + 1/4*3^3/4^3 + 3/4*3^3/4^3 + ...
|
|
; c2 = 1/4 + 3/4*3/4 + 1/4*3^2/4^2 + 3/4*3^3/4^3 + 1/4*3^3/4^3 + ...
|
|
;
|
|
; Simplify by splitting up the odd and even terms of the series and taking out
|
|
; factors so that the infite series matches:
|
|
;
|
|
; c1 = 3/4 *(9^0/16^0 + 9^1/16^1 + 9^2/16^2 + ...)
|
|
; + 3/16*(9^0/16^0 + 9^1/16^1 + 9^2/16^2 + ...)
|
|
; c2 = 1/4 *(9^0/16^0 + 9^1/16^1 + 9^2/16^2 + ...)
|
|
; + 9/16*(9^0/16^0 + 9^1/16^1 + 9^2/16^2 + ...)
|
|
;
|
|
; c1 = 15/16*(9^0/16^0 + 9^1/16^1 + 9^2/16^2 + ...)
|
|
; c2 = 13/16*(9^0/16^0 + 9^1/16^1 + 9^2/16^2 + ...)
|
|
;
|
|
; Since this geometric series sums to 16/7:
|
|
;
|
|
; c1 = 15/7
|
|
; c2 = 13/7
|
|
;
|
|
; If we treat c1 and c2 as members of the same loop, the exit frequency of the
|
|
; loop as a whole is 1/4, so the loop scale should be 4. Summing c1 and c2
|
|
; gives 28/7, or 4.0, which is nice confirmation of the math above.
|
|
;
|
|
; -block-freq currently treats the two nodes as equals.
|
|
define void @multientry(i1 %x) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'multientry':
|
|
; CHECK-NEXT: block-frequency-info: multientry
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
br i1 %x, label %c1, label %c2, !prof !2
|
|
|
|
c1:
|
|
; CHECK-NEXT: c1: float = 2.0,
|
|
; The "correct" answer is: float = 2.142857{{[0-9]*}},
|
|
br i1 %x, label %c2, label %exit, !prof !2
|
|
|
|
c2:
|
|
; CHECK-NEXT: c2: float = 2.0,
|
|
; The "correct" answer is: float = 1.857142{{[0-9]*}},
|
|
br i1 %x, label %c1, label %exit, !prof !2
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
|
|
!2 = !{!"branch_weights", i32 3, i32 1}
|
|
|
|
; Testcase #2
|
|
; ===========
|
|
;
|
|
; In this case c1 and c2 should be treated as equals in a single loop. The
|
|
; exit frequency is 1/3, so the scaling factor for the loop should be 3.0. The
|
|
; loop is entered 2/3 of the time, and c1 and c2 split the total loop frequency
|
|
; evenly (1/2), so they should each have frequencies of 1.0 (3.0*2/3*1/2).
|
|
; Another way of computing this result is by assigning 1.0 to entry and showing
|
|
; that c1 and c2 should accumulate frequencies of:
|
|
;
|
|
; 1/3 + 2/9 + 4/27 + 8/81 + ...
|
|
; 2^0/3^1 + 2^1/3^2 + 2^2/3^3 + 2^3/3^4 + ...
|
|
;
|
|
; At the first step, c1 and c2 each get 1/3 of the entry. At each subsequent
|
|
; step, c1 and c2 each get 1/3 of what's left in c1 and c2 combined. This
|
|
; infinite series sums to 1.
|
|
define void @crossloops(i2 %x) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'crossloops':
|
|
; CHECK-NEXT: block-frequency-info: crossloops
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
switch i2 %x, label %exit [ i2 1, label %c1
|
|
i2 2, label %c2 ], !prof !3
|
|
|
|
c1:
|
|
; CHECK-NEXT: c1: float = 1.0,
|
|
switch i2 %x, label %exit [ i2 1, label %c1
|
|
i2 2, label %c2 ], !prof !3
|
|
|
|
c2:
|
|
; CHECK-NEXT: c2: float = 1.0,
|
|
switch i2 %x, label %exit [ i2 1, label %c1
|
|
i2 2, label %c2 ], !prof !3
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
|
|
!3 = !{!"branch_weights", i32 2, i32 2, i32 2}
|
|
|
|
; A true loop with irreducible control flow inside.
|
|
define void @loop_around_irreducible(i1 %x) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'loop_around_irreducible':
|
|
; CHECK-NEXT: block-frequency-info: loop_around_irreducible
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
br label %loop
|
|
|
|
loop:
|
|
; CHECK-NEXT: loop: float = 4.0, int = [[HEAD:[0-9]+]]
|
|
br i1 %x, label %left, label %right, !prof !4
|
|
|
|
left:
|
|
; CHECK-NEXT: left: float = 8.0,
|
|
br i1 %x, label %right, label %loop.end, !prof !5
|
|
|
|
right:
|
|
; CHECK-NEXT: right: float = 8.0,
|
|
br i1 %x, label %left, label %loop.end, !prof !5
|
|
|
|
loop.end:
|
|
; CHECK-NEXT: loop.end: float = 4.0, int = [[HEAD]]
|
|
br i1 %x, label %loop, label %exit, !prof !5
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
!4 = !{!"branch_weights", i32 1, i32 1}
|
|
!5 = !{!"branch_weights", i32 3, i32 1}
|
|
|
|
; Two unrelated irreducible SCCs.
|
|
define void @two_sccs(i1 %x) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'two_sccs':
|
|
; CHECK-NEXT: block-frequency-info: two_sccs
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
br i1 %x, label %a, label %b, !prof !6
|
|
|
|
a:
|
|
; CHECK-NEXT: a: float = 0.75,
|
|
br i1 %x, label %a.left, label %a.right, !prof !7
|
|
|
|
a.left:
|
|
; CHECK-NEXT: a.left: float = 1.5,
|
|
br i1 %x, label %a.right, label %exit, !prof !6
|
|
|
|
a.right:
|
|
; CHECK-NEXT: a.right: float = 1.5,
|
|
br i1 %x, label %a.left, label %exit, !prof !6
|
|
|
|
b:
|
|
; CHECK-NEXT: b: float = 0.25,
|
|
br i1 %x, label %b.left, label %b.right, !prof !7
|
|
|
|
b.left:
|
|
; CHECK-NEXT: b.left: float = 0.625,
|
|
br i1 %x, label %b.right, label %exit, !prof !8
|
|
|
|
b.right:
|
|
; CHECK-NEXT: b.right: float = 0.625,
|
|
br i1 %x, label %b.left, label %exit, !prof !8
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
!6 = !{!"branch_weights", i32 3, i32 1}
|
|
!7 = !{!"branch_weights", i32 1, i32 1}
|
|
!8 = !{!"branch_weights", i32 4, i32 1}
|
|
|
|
; A true loop inside irreducible control flow.
|
|
define void @loop_inside_irreducible(i1 %x) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'loop_inside_irreducible':
|
|
; CHECK-NEXT: block-frequency-info: loop_inside_irreducible
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
br i1 %x, label %left, label %right, !prof !9
|
|
|
|
left:
|
|
; CHECK-NEXT: left: float = 2.0,
|
|
br i1 %x, label %right, label %exit, !prof !10
|
|
|
|
right:
|
|
; CHECK-NEXT: right: float = 2.0, int = [[RIGHT:[0-9]+]]
|
|
br label %loop
|
|
|
|
loop:
|
|
; CHECK-NEXT: loop: float = 6.0,
|
|
br i1 %x, label %loop, label %right.end, !prof !11
|
|
|
|
right.end:
|
|
; CHECK-NEXT: right.end: float = 2.0, int = [[RIGHT]]
|
|
br i1 %x, label %left, label %exit, !prof !10
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
!9 = !{!"branch_weights", i32 1, i32 1}
|
|
!10 = !{!"branch_weights", i32 3, i32 1}
|
|
!11 = !{!"branch_weights", i32 2, i32 1}
|
|
|
|
; Irreducible control flow in a branch that's in a true loop.
|
|
define void @loop_around_branch_with_irreducible(i1 %x) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'loop_around_branch_with_irreducible':
|
|
; CHECK-NEXT: block-frequency-info: loop_around_branch_with_irreducible
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
br label %loop
|
|
|
|
loop:
|
|
; CHECK-NEXT: loop: float = 2.0, int = [[LOOP:[0-9]+]]
|
|
br i1 %x, label %normal, label %irreducible.entry, !prof !12
|
|
|
|
normal:
|
|
; CHECK-NEXT: normal: float = 1.5,
|
|
br label %loop.end
|
|
|
|
irreducible.entry:
|
|
; CHECK-NEXT: irreducible.entry: float = 0.5, int = [[IRREDUCIBLE:[0-9]+]]
|
|
br i1 %x, label %left, label %right, !prof !13
|
|
|
|
left:
|
|
; CHECK-NEXT: left: float = 1.0,
|
|
br i1 %x, label %right, label %irreducible.exit, !prof !12
|
|
|
|
right:
|
|
; CHECK-NEXT: right: float = 1.0,
|
|
br i1 %x, label %left, label %irreducible.exit, !prof !12
|
|
|
|
irreducible.exit:
|
|
; CHECK-NEXT: irreducible.exit: float = 0.5, int = [[IRREDUCIBLE]]
|
|
br label %loop.end
|
|
|
|
loop.end:
|
|
; CHECK-NEXT: loop.end: float = 2.0, int = [[LOOP]]
|
|
br i1 %x, label %loop, label %exit, !prof !13
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
!12 = !{!"branch_weights", i32 3, i32 1}
|
|
!13 = !{!"branch_weights", i32 1, i32 1}
|
|
|
|
; Irreducible control flow between two true loops.
|
|
define void @loop_around_branch_with_irreducible_around_loop(i1 %x) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'loop_around_branch_with_irreducible_around_loop':
|
|
; CHECK-NEXT: block-frequency-info: loop_around_branch_with_irreducible_around_loop
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
br label %loop
|
|
|
|
loop:
|
|
; CHECK-NEXT: loop: float = 3.0, int = [[LOOP:[0-9]+]]
|
|
br i1 %x, label %normal, label %irreducible, !prof !14
|
|
|
|
normal:
|
|
; CHECK-NEXT: normal: float = 2.0,
|
|
br label %loop.end
|
|
|
|
irreducible:
|
|
; CHECK-NEXT: irreducible: float = 1.0,
|
|
br i1 %x, label %left, label %right, !prof !15
|
|
|
|
left:
|
|
; CHECK-NEXT: left: float = 2.0,
|
|
br i1 %x, label %right, label %loop.end, !prof !16
|
|
|
|
right:
|
|
; CHECK-NEXT: right: float = 2.0, int = [[RIGHT:[0-9]+]]
|
|
br label %right.loop
|
|
|
|
right.loop:
|
|
; CHECK-NEXT: right.loop: float = 10.0,
|
|
br i1 %x, label %right.loop, label %right.end, !prof !17
|
|
|
|
right.end:
|
|
; CHECK-NEXT: right.end: float = 2.0, int = [[RIGHT]]
|
|
br i1 %x, label %left, label %loop.end, !prof !16
|
|
|
|
loop.end:
|
|
; CHECK-NEXT: loop.end: float = 3.0, int = [[LOOP]]
|
|
br i1 %x, label %loop, label %exit, !prof !14
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
!14 = !{!"branch_weights", i32 2, i32 1}
|
|
!15 = !{!"branch_weights", i32 1, i32 1}
|
|
!16 = !{!"branch_weights", i32 3, i32 1}
|
|
!17 = !{!"branch_weights", i32 4, i32 1}
|
|
|
|
; An irreducible SCC with a non-header.
|
|
define void @nonheader(i1 %x) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'nonheader':
|
|
; CHECK-NEXT: block-frequency-info: nonheader
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
br i1 %x, label %left, label %right, !prof !18
|
|
|
|
left:
|
|
; CHECK-NEXT: left: float = 1.0,
|
|
br i1 %x, label %bottom, label %exit, !prof !19
|
|
|
|
right:
|
|
; CHECK-NEXT: right: float = 1.0,
|
|
br i1 %x, label %bottom, label %exit, !prof !20
|
|
|
|
bottom:
|
|
; CHECK-NEXT: bottom: float = 1.0,
|
|
br i1 %x, label %left, label %right, !prof !18
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
!18 = !{!"branch_weights", i32 1, i32 1}
|
|
!19 = !{!"branch_weights", i32 1, i32 3}
|
|
!20 = !{!"branch_weights", i32 3, i32 1}
|
|
|
|
; An irreducible SCC with an irreducible sub-SCC. In the current version of
|
|
; -block-freq, this means an extra header.
|
|
;
|
|
; This testcases uses non-trivial branch weights. The CHECK statements here
|
|
; will start to fail if we change -block-freq to be more accurate. Currently,
|
|
; loop headers are affected by the weight of their corresponding back edges.
|
|
define void @nonentry_header(i1 %x, i2 %y) {
|
|
; CHECK-LABEL: Printing analysis {{.*}} for function 'nonentry_header':
|
|
; CHECK-NEXT: block-frequency-info: nonentry_header
|
|
entry:
|
|
; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
|
|
br i1 %x, label %left, label %right, !prof !21
|
|
|
|
left:
|
|
; CHECK-NEXT: left: float = 0.14
|
|
br i1 %x, label %top, label %bottom, !prof !22
|
|
|
|
right:
|
|
; CHECK-NEXT: right: float = 0.42
|
|
br i1 %x, label %top, label %bottom, !prof !22
|
|
|
|
top:
|
|
; CHECK-NEXT: top: float = 8.43
|
|
switch i2 %y, label %exit [ i2 0, label %left
|
|
i2 1, label %right
|
|
i2 2, label %bottom ], !prof !23
|
|
|
|
bottom:
|
|
; CHECK-NEXT: bottom: float = 4.5,
|
|
br label %top
|
|
|
|
exit:
|
|
; CHECK-NEXT: exit: float = 1.0, int = [[ENTRY]]
|
|
ret void
|
|
}
|
|
!21 = !{!"branch_weights", i32 2, i32 1}
|
|
!22 = !{!"branch_weights", i32 1, i32 1}
|
|
!23 = !{!"branch_weights", i32 8, i32 1, i32 3, i32 12}
|