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llvm-mirror/test/CodeGen/X86/switch.ll
Cong Hou e29dba6476 Distribute the weight on the edge from switch to default statement to edges generated in lowering switch. 
Currently, when edge weights are assigned to edges that are created when lowering switch statement, the weight on the edge to default statement (let's call it "default weight" here) is not considered. We need to distribute this weight properly. However, without value profiling, we have no idea how to distribute it. In this patch, I applied the heuristic that this weight is evenly distributed to successors.

For example, given a switch statement with cases 1,2,3,5,10,11,20, and every edge from switch to each successor has weight 10. If there is a binary search tree built to test if n < 10, then its two out-edges will have weight 4x10+10/2 = 45 and 3x10 + 10/2 = 35 respectively (currently they are 40 and 30 without considering the default weight). Each distribution (which is 5 here) will be stored in each SwitchWorkListItem for further distribution.

There are some exceptions:

For a jump table header which doesn't have any edge to default statement, we don't distribute the default weight to it.
For a bit test header which covers a contiguous range and hence has no edges to default statement, we don't distribute the default weight to it.
When the branch checks a single value or a contiguous range with no edge to default statement, we don't distribute the default weight to it.
In other cases, the default weight is evenly distributed to successors.

Differential Revision: http://reviews.llvm.org/D12418

llvm-svn: 246522
2015-09-01 01:42:16 +00:00

708 lines
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; RUN: llc -mtriple=x86_64-linux-gnu %s -o - | FileCheck %s
; RUN: llc -mtriple=x86_64-linux-gnu %s -o - -O0 | FileCheck --check-prefix=NOOPT %s
declare void @g(i32)
define void @basic(i32 %x) {
entry:
switch i32 %x, label %return [
i32 3, label %bb0
i32 1, label %bb1
i32 4, label %bb1
i32 5, label %bb2
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 1) br label %return
return: ret void
; Lowered as a jump table, both with and without optimization.
; CHECK-LABEL: basic
; CHECK: decl
; CHECK: cmpl $4
; CHECK: ja
; CHECK: jmpq *.LJTI
; NOOPT-LABEL: basic
; NOOPT: decl
; NOOPT: subl $4
; NOOPT: ja
; NOOPT: movq .LJTI
; NOOPT: jmpq
}
define void @simple_ranges(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 1, label %bb0
i32 2, label %bb0
i32 3, label %bb0
i32 100, label %bb1
i32 101, label %bb1
i32 102, label %bb1
i32 103, label %bb1
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
return: ret void
; Should be lowered to two range checks.
; CHECK-LABEL: simple_ranges
; CHECK: leal -100
; CHECK: cmpl $4
; CHECK: jb
; CHECK: cmpl $3
; CHECK: ja
; We do this even at -O0, because it's cheap and makes codegen faster.
; NOOPT-LABEL: simple_ranges
; NOOPT: subl $4
; NOOPT: jb
; NOOPT: addl $-100
; NOOPT: subl $4
; NOOPT: jb
}
define void @jt_is_better(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 2, label %bb0
i32 4, label %bb0
i32 1, label %bb1
i32 3, label %bb1
i32 5, label %bb1
i32 6, label %bb2
i32 7, label %bb3
i32 8, label %bb4
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
return: ret void
; Cases 0-5 could be lowered with two bit tests,
; but with 6-8, the whole switch is suitable for a jump table.
; CHECK-LABEL: jt_is_better
; CHECK: cmpl $8
; CHECK: ja
; CHECK: jmpq *.LJTI
}
define void @bt_is_better(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 3, label %bb0
i32 6, label %bb0
i32 1, label %bb1
i32 4, label %bb1
i32 7, label %bb1
i32 2, label %bb2
i32 5, label %bb2
i32 8, label %bb2
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
return: ret void
; This could be lowered as a jump table, but bit tests is more efficient.
; CHECK-LABEL: bt_is_better
; The bit test on 2,5,8 is unnecessary as all cases cover the rage [0, 8].
; The range check guarantees that cases other than 0,3,6 and 1,4,7 must be
; in 2,5,8.
;
; 73 = 2^0 + 2^3 + 2^6
; CHECK: movl $73
; CHECK: btl
; 146 = 2^1 + 2^4 + 2^7
; CHECK: movl $146
; CHECK: btl
; 292 = 2^2 + 2^5 + 2^8
; CHECK-NOT: movl $292
; CHECK-NOT: btl
}
define void @bt_is_better2(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 3, label %bb0
i32 6, label %bb0
i32 1, label %bb1
i32 4, label %bb1
i32 7, label %bb1
i32 2, label %bb2
i32 8, label %bb2
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
return: ret void
; This will also be lowered as bit test, but as the range [0,8] is not fully
; covered (5 missing), the default statement can be jumped to and we end up
; with one more branch.
; CHECK-LABEL: bt_is_better2
;
; 73 = 2^0 + 2^3 + 2^6
; CHECK: movl $73
; CHECK: btl
; 146 = 2^1 + 2^4 + 2^7
; CHECK: movl $146
; CHECK: btl
; 260 = 2^2 + 2^8
; CHECK: movl $260
; CHECK: btl
}
define void @bt_is_better3(i32 %x) {
entry:
switch i32 %x, label %return [
i32 10, label %bb0
i32 13, label %bb0
i32 16, label %bb0
i32 11, label %bb1
i32 14, label %bb1
i32 17, label %bb1
i32 12, label %bb2
i32 18, label %bb2
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
return: ret void
; We don't have to subtract 10 from the case value to let the range become
; [0, 8], as each value in the range [10, 18] can be represented by bits in a
; word. Then we still need a branch to jump to the default statement for the
; range [0, 10).
; CHECK-LABEL: bt_is_better3
;
; 74752 = 2^10 + 2^13 + 2^16
; CHECK: movl $74752
; CHECK: btl
; 149504 = 2^11 + 2^14 + 2^17
; CHECK: movl $149504
; CHECK: btl
; 266240 = 2^12 + 2^15 + 2^18
; CHECK: movl $266240
; CHECK: btl
}
define void @optimal_pivot1(i32 %x) {
entry:
switch i32 %x, label %return [
i32 100, label %bb0
i32 200, label %bb1
i32 300, label %bb0
i32 400, label %bb1
i32 500, label %bb0
i32 600, label %bb1
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
return: ret void
; Should pivot around 400 for two subtrees of equal size.
; CHECK-LABEL: optimal_pivot1
; CHECK-NOT: cmpl
; CHECK: cmpl $399
}
define void @optimal_pivot2(i32 %x) {
entry:
switch i32 %x, label %return [
i32 100, label %bb0 i32 101, label %bb1 i32 102, label %bb2 i32 103, label %bb3
i32 200, label %bb0 i32 201, label %bb1 i32 202, label %bb2 i32 203, label %bb3
i32 300, label %bb0 i32 301, label %bb1 i32 302, label %bb2 i32 303, label %bb3
i32 400, label %bb0 i32 401, label %bb1 i32 402, label %bb2 i32 403, label %bb3
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
return: ret void
; Should pivot around 300 for two subtrees with two jump tables each.
; CHECK-LABEL: optimal_pivot2
; CHECK-NOT: cmpl
; CHECK: cmpl $299
; CHECK: jmpq *.LJTI
; CHECK: jmpq *.LJTI
; CHECK: jmpq *.LJTI
; CHECK: jmpq *.LJTI
}
define void @optimal_jump_table1(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 5, label %bb1
i32 6, label %bb2
i32 12, label %bb3
i32 13, label %bb4
i32 15, label %bb5
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
bb5: tail call void @g(i32 5) br label %return
return: ret void
; Splitting in the largest gap (between 6 and 12) would yield suboptimal result.
; Expecting a jump table from 5 to 15.
; CHECK-LABEL: optimal_jump_table1
; CHECK: leal -5
; CHECK: cmpl $10
; CHECK: jmpq *.LJTI
; At -O0, we don't build jump tables for only parts of a switch.
; NOOPT-LABEL: optimal_jump_table1
; NOOPT: testl %edi, %edi
; NOOPT: je
; NOOPT: subl $5, %eax
; NOOPT: je
; NOOPT: subl $6, %eax
; NOOPT: je
; NOOPT: subl $12, %eax
; NOOPT: je
; NOOPT: subl $13, %eax
; NOOPT: je
; NOOPT: subl $15, %eax
; NOOPT: je
}
define void @optimal_jump_table2(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 1, label %bb1
i32 2, label %bb2
i32 9, label %bb3
i32 14, label %bb4
i32 15, label %bb5
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
bb5: tail call void @g(i32 5) br label %return
return: ret void
; Partitioning the cases to the minimum number of dense sets is not good enough.
; This can be partitioned as {0,1,2,9},{14,15} or {0,1,2},{9,14,15}. The former
; should be preferred. Expecting a table from 0-9.
; CHECK-LABEL: optimal_jump_table2
; CHECK: cmpl $9
; CHECK: jmpq *.LJTI
}
define void @optimal_jump_table3(i32 %x) {
entry:
switch i32 %x, label %return [
i32 1, label %bb0
i32 2, label %bb1
i32 3, label %bb2
i32 10, label %bb3
i32 13, label %bb0
i32 14, label %bb1
i32 15, label %bb2
i32 20, label %bb3
i32 25, label %bb4
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
return: ret void
; Splitting to maximize left-right density sum and gap size would split this
; between 3 and 10, and then between 20 and 25. It's better to build a table
; from 1-20.
; CHECK-LABEL: optimal_jump_table3
; CHECK: leal -1
; CHECK: cmpl $19
; CHECK: jmpq *.LJTI
}
%struct.S = type { %struct.S*, i32 }
define void @phi_node_trouble(%struct.S* %s) {
entry:
br label %header
header:
%ptr = phi %struct.S* [ %s, %entry ], [ %next, %loop ]
%bool = icmp eq %struct.S* %ptr, null
br i1 %bool, label %exit, label %loop
loop:
%nextptr = getelementptr inbounds %struct.S, %struct.S* %ptr, i64 0, i32 0
%next = load %struct.S*, %struct.S** %nextptr
%xptr = getelementptr inbounds %struct.S, %struct.S* %next, i64 0, i32 1
%x = load i32, i32* %xptr
switch i32 %x, label %exit [
i32 4, label %header
i32 36, label %exit2
i32 69, label %exit2
i32 25, label %exit2
]
exit:
ret void
exit2:
ret void
; This will be lowered to a comparison with 4 and then bit tests. Make sure
; that the phi node in %header gets a value from the comparison block.
; CHECK-LABEL: phi_node_trouble
; CHECK: movq (%[[REG1:[a-z]+]]), %[[REG1]]
; CHECK: movl 8(%[[REG1]]), %[[REG2:[a-z]+]]
; CHECK: cmpl $4, %[[REG2]]
}
define void @default_only(i32 %x) {
entry:
br label %sw
return:
ret void
sw:
switch i32 %x, label %return [
]
; Branch directly to the default.
; (In optimized builds the switch is removed earlier.)
; NOOPT-LABEL: default_only
; NOOPT: .[[L:[A-Z0-9_]+]]:
; NOOPT-NEXT: retq
; NOOPT: jmp .[[L]]
}
define void @int_max_table_cluster(i8 %x) {
entry:
switch i8 %x, label %return [
i8 0, label %bb0 i8 1, label %bb0 i8 2, label %bb0 i8 3, label %bb0
i8 4, label %bb0 i8 5, label %bb0 i8 6, label %bb0 i8 7, label %bb0
i8 8, label %bb0 i8 9, label %bb0 i8 10, label %bb0 i8 11, label %bb0
i8 12, label %bb0 i8 13, label %bb0 i8 14, label %bb0 i8 15, label %bb0
i8 16, label %bb0 i8 17, label %bb0 i8 18, label %bb0 i8 19, label %bb0
i8 20, label %bb0 i8 21, label %bb0 i8 22, label %bb0 i8 23, label %bb0
i8 24, label %bb0 i8 25, label %bb0 i8 26, label %bb0 i8 27, label %bb0
i8 28, label %bb0 i8 29, label %bb0 i8 30, label %bb0 i8 31, label %bb0
i8 32, label %bb0 i8 33, label %bb0 i8 34, label %bb0 i8 35, label %bb0
i8 36, label %bb0 i8 37, label %bb0 i8 38, label %bb0 i8 39, label %bb0
i8 40, label %bb0 i8 41, label %bb0 i8 42, label %bb0 i8 43, label %bb0
i8 44, label %bb0 i8 45, label %bb0 i8 46, label %bb0 i8 47, label %bb0
i8 48, label %bb0 i8 49, label %bb0 i8 50, label %bb0 i8 51, label %bb0
i8 52, label %bb0 i8 53, label %bb0 i8 54, label %bb0 i8 55, label %bb0
i8 56, label %bb0 i8 57, label %bb0 i8 58, label %bb0 i8 59, label %bb0
i8 60, label %bb0 i8 61, label %bb0 i8 62, label %bb0 i8 63, label %bb0
i8 64, label %bb0 i8 65, label %bb0 i8 66, label %bb0 i8 67, label %bb0
i8 68, label %bb0 i8 69, label %bb0 i8 70, label %bb0 i8 71, label %bb0
i8 72, label %bb0 i8 73, label %bb0 i8 74, label %bb0 i8 75, label %bb0
i8 76, label %bb0 i8 77, label %bb0 i8 78, label %bb0 i8 79, label %bb0
i8 80, label %bb0 i8 81, label %bb0 i8 82, label %bb0 i8 83, label %bb0
i8 84, label %bb0 i8 85, label %bb0 i8 86, label %bb0 i8 87, label %bb0
i8 88, label %bb0 i8 89, label %bb0 i8 90, label %bb0 i8 91, label %bb0
i8 92, label %bb0 i8 93, label %bb0 i8 94, label %bb0 i8 95, label %bb0
i8 96, label %bb0 i8 97, label %bb0 i8 98, label %bb0 i8 99, label %bb0
i8 100, label %bb0 i8 101, label %bb0 i8 102, label %bb0 i8 103, label %bb0
i8 104, label %bb0 i8 105, label %bb0 i8 106, label %bb0 i8 107, label %bb0
i8 108, label %bb0 i8 109, label %bb0 i8 110, label %bb0 i8 111, label %bb0
i8 112, label %bb0 i8 113, label %bb0 i8 114, label %bb0 i8 115, label %bb0
i8 116, label %bb0 i8 117, label %bb0 i8 118, label %bb0 i8 119, label %bb0
i8 120, label %bb0 i8 121, label %bb0 i8 122, label %bb0 i8 123, label %bb0
i8 124, label %bb0 i8 125, label %bb0 i8 126, label %bb0 i8 127, label %bb0
i8 -64, label %bb1 i8 -63, label %bb1 i8 -62, label %bb1 i8 -61, label %bb1
i8 -60, label %bb1 i8 -59, label %bb1 i8 -58, label %bb1 i8 -57, label %bb1
i8 -56, label %bb1 i8 -55, label %bb1 i8 -54, label %bb1 i8 -53, label %bb1
i8 -52, label %bb1 i8 -51, label %bb1 i8 -50, label %bb1 i8 -49, label %bb1
i8 -48, label %bb1 i8 -47, label %bb1 i8 -46, label %bb1 i8 -45, label %bb1
i8 -44, label %bb1 i8 -43, label %bb1 i8 -42, label %bb1 i8 -41, label %bb1
i8 -40, label %bb1 i8 -39, label %bb1 i8 -38, label %bb1 i8 -37, label %bb1
i8 -36, label %bb1 i8 -35, label %bb1 i8 -34, label %bb1 i8 -33, label %bb1
i8 -32, label %bb2 i8 -31, label %bb2 i8 -30, label %bb2 i8 -29, label %bb2
i8 -28, label %bb2 i8 -27, label %bb2 i8 -26, label %bb2 i8 -25, label %bb2
i8 -24, label %bb2 i8 -23, label %bb2 i8 -22, label %bb2 i8 -21, label %bb2
i8 -20, label %bb2 i8 -19, label %bb2 i8 -18, label %bb2 i8 -17, label %bb2
i8 -16, label %bb3 i8 -15, label %bb3 i8 -14, label %bb3 i8 -13, label %bb3
i8 -12, label %bb3 i8 -11, label %bb3 i8 -10, label %bb3 i8 -9, label %bb3
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 1) br label %return
bb3: tail call void @g(i32 1) br label %return
return: ret void
; Don't infloop on jump tables where the upper bound is the max value of the
; input type (in this case 127).
; CHECK-LABEL: int_max_table_cluster
; CHECK: jmpq *.LJTI
}
define void @bt_order_by_weight(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 3, label %bb0
i32 6, label %bb0
i32 1, label %bb1
i32 4, label %bb1
i32 7, label %bb1
i32 2, label %bb2
i32 5, label %bb2
i32 8, label %bb2
i32 9, label %bb2
], !prof !1
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
return: ret void
; Cases 1,4,7 have a very large branch weight (which shouldn't overflow), so
; their bit test should come first. 0,3,6 and 2,5,8,9 both have a weight of 12,
; but the latter set has more cases, so should be tested for earlier.
; The bit test on 0,3,6 is unnecessary as all cases cover the rage [0, 9].
; The range check guarantees that cases other than 1,4,7 and 2,5,8,9 must be
; in 0,3,6.
; CHECK-LABEL: bt_order_by_weight
; 146 = 2^1 + 2^4 + 2^7
; CHECK: movl $146
; CHECK: btl
; 292 = 2^2 + 2^5 + 2^8 + 2^9
; CHECK: movl $804
; CHECK: btl
; 73 = 2^0 + 2^3 + 2^6
; CHECK-NOT: movl $73
; CHECK-NOT: btl
}
!1 = !{!"branch_weights",
; Default:
i32 1,
; Cases 0,3,6:
i32 4, i32 4, i32 4,
; Cases 1,4,7:
i32 4294967295, i32 2, i32 4294967295,
; Cases 2,5,8,9:
i32 3, i32 3, i32 3, i32 3}
define void @order_by_weight_and_fallthrough(i32 %x) {
entry:
switch i32 %x, label %return [
i32 100, label %bb1
i32 200, label %bb0
i32 300, label %bb0
], !prof !2
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
return: ret void
; Case 200 has the highest weight and should come first. 100 and 300 have the
; same weight, but 300 goes to the 'next' block, so should be last.
; CHECK-LABEL: order_by_weight_and_fallthrough
; CHECK: cmpl $200
; CHECK: cmpl $100
; CHECK: cmpl $300
}
!2 = !{!"branch_weights",
; Default:
i32 1,
; Case 100:
i32 10,
; Case 200:
i32 1000,
; Case 300:
i32 10}
define void @zero_weight_tree(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 10, label %bb1
i32 20, label %bb2
i32 30, label %bb3
i32 40, label %bb4
i32 50, label %bb5
], !prof !3
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
bb5: tail call void @g(i32 5) br label %return
return: ret void
; Make sure to pick a pivot in the middle also with zero-weight cases.
; CHECK-LABEL: zero_weight_tree
; CHECK-NOT: cmpl
; CHECK: cmpl $29
}
!3 = !{!"branch_weights", i32 1, i32 10, i32 0, i32 0, i32 0, i32 0, i32 10}
define void @left_leaning_weight_balanced_tree(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 10, label %bb1
i32 20, label %bb2
i32 30, label %bb3
i32 40, label %bb4
i32 50, label %bb5
i32 60, label %bb6
i32 70, label %bb6
], !prof !4
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
bb5: tail call void @g(i32 5) br label %return
bb6: tail call void @g(i32 6) br label %return
bb7: tail call void @g(i32 7) br label %return
return: ret void
; Without branch probabilities, the pivot would be 40, since that would yield
; equal-sized sub-trees. When taking weights into account, case 70 becomes the
; pivot. Since there is room for 3 cases in a leaf, cases 50 and 60 are also
; included in the right-hand side because that doesn't reduce their rank.
; CHECK-LABEL: left_leaning_weight_balanced_tree
; CHECK-NOT: cmpl
; CHECK: cmpl $49
}
!4 = !{!"branch_weights", i32 1, i32 10, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1000}
define void @left_leaning_weight_balanced_tree2(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 10, label %bb1
i32 20, label %bb2
i32 30, label %bb3
i32 40, label %bb4
i32 50, label %bb5
i32 60, label %bb6
i32 70, label %bb6
], !prof !5
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
bb5: tail call void @g(i32 5) br label %return
bb6: tail call void @g(i32 6) br label %return
bb7: tail call void @g(i32 7) br label %return
return: ret void
; Same as the previous test, except case 50 has higher rank to the left than it
; would have on the right. Case 60 would have the same rank on both sides, so is
; moved into the leaf.
; CHECK-LABEL: left_leaning_weight_balanced_tree2
; CHECK-NOT: cmpl
; CHECK: cmpl $59
}
!5 = !{!"branch_weights", i32 1, i32 10, i32 1, i32 1, i32 1, i32 1, i32 90, i32 70, i32 1000}
define void @right_leaning_weight_balanced_tree(i32 %x) {
entry:
switch i32 %x, label %return [
i32 0, label %bb0
i32 10, label %bb1
i32 20, label %bb2
i32 30, label %bb3
i32 40, label %bb4
i32 50, label %bb5
i32 60, label %bb6
i32 70, label %bb6
], !prof !6
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
bb5: tail call void @g(i32 5) br label %return
bb6: tail call void @g(i32 6) br label %return
bb7: tail call void @g(i32 7) br label %return
return: ret void
; Analogous to left_leaning_weight_balanced_tree.
; CHECK-LABEL: right_leaning_weight_balanced_tree
; CHECK-NOT: cmpl
; CHECK: cmpl $19
}
!6 = !{!"branch_weights", i32 1, i32 1000, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 10}
define void @jump_table_affects_balance(i32 %x) {
entry:
switch i32 %x, label %return [
; Jump table:
i32 0, label %bb0
i32 1, label %bb1
i32 2, label %bb2
i32 3, label %bb3
i32 100, label %bb0
i32 200, label %bb1
i32 300, label %bb2
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
return: ret void
; CHECK-LABEL: jump_table_affects_balance
; If the tree were balanced based on number of clusters, {0-3,100} would go on
; the left and {200,300} on the right. However, the jump table weights as much
; as its components, so 100 is selected as the pivot.
; CHECK-NOT: cmpl
; CHECK: cmpl $99
}
define void @pr23738(i4 %x) {
entry:
switch i4 %x, label %bb0 [
i4 0, label %bb1
i4 1, label %bb1
i4 -5, label %bb1
]
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
return: ret void
; Don't assert due to truncating the bitwidth (64) to i4 when checking
; that the bit-test range fits in a word.
}
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