--- /dev/null
+; 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 %bb0
+ ]
+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 as straight compares in -O0 mode.
+; NOOPT-LABEL: basic
+; NOOPT: subl $3, %eax
+; NOOPT: je
+; NOOPT: subl $1, %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
+}
+
+
+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]]
+}
projects / oota-llvm.git / blobdiff