; 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 ; Should be lowered as straight compares in -O0 mode. ; NOOPT-LABEL: basic ; NOOPT: subl $1, %eax ; NOOPT: je ; NOOPT: subl $3, %eax ; NOOPT: je ; NOOPT: subl $4, %eax ; NOOPT: je ; NOOPT: subl $5, %eax ; NOOPT: je ; Jump table otherwise. ; CHECK-LABEL: basic ; CHECK: decl ; CHECK: cmpl $4 ; CHECK: ja ; CHECK: jmpq *.LJTI } 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: jae ; 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: jbe ; 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 ; 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: movl $292 ; 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 } 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. ; 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: movl $73 ; CHECK: 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 ], !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 return: ret void ; To balance the tree by weight, the pivot is shifted to the right, moving hot ; cases closer to the root. ; CHECK-LABEL: left_leaning_weight_balanced_tree ; CHECK-NOT: cmpl ; CHECK: cmpl $39 } !4 = !{!"branch_weights", i32 1, i32 10, i32 1, i32 1, i32 1, i32 10, 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. }