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SimplifyCFG: preserve branch-weight metadata when creating a new switch from a pair of switch/branch where both depend on the value of the same variable and the default case of the first switch/branch goes to the second switch/branch. Code clean up and fixed a few issues: 1> handling the case where some cases of the 2nd switch are invalidated 2> correctly calculate the weight for the 2nd switch when it is a conditional eq Testing case is modified from Alastair's original patch. llvm-svn: 163635
2012-09-12 01:43:35 +08:00
; RUN: opt -simplifycfg -S -o - < %s | FileCheck %s
declare void @func2(i32)
declare void @func4(i32)
declare void @func6(i32)
declare void @func8(i32)
;; test1 - create a switch with case 2 and case 4 from two branches: N == 2
;; and N == 4.
define void @test1(i32 %N) nounwind uwtable {
entry:
%cmp = icmp eq i32 %N, 2
br i1 %cmp, label %if.then, label %if.else, !prof !0
; CHECK: test1
; CHECK: switch i32 %N
; CHECK: ], !prof !0
if.then:
call void @func2(i32 %N) nounwind
br label %if.end9
if.else:
%cmp2 = icmp eq i32 %N, 4
br i1 %cmp2, label %if.then7, label %if.else8, !prof !1
if.then7:
call void @func4(i32 %N) nounwind
br label %if.end
if.else8:
call void @func8(i32 %N) nounwind
br label %if.end
if.end:
br label %if.end9
if.end9:
ret void
}
;; test2 - Merge two switches where PredDefault == BB.
define void @test2(i32 %M, i32 %N) nounwind uwtable {
entry:
%cmp = icmp sgt i32 %M, 2
br i1 %cmp, label %sw1, label %sw2
sw1:
switch i32 %N, label %sw2 [
i32 2, label %sw.bb
i32 3, label %sw.bb1
], !prof !2
; CHECK: test2
; CHECK: switch i32 %N, label %sw.epilog
; CHECK: i32 2, label %sw.bb
; CHECK: i32 3, label %sw.bb1
; CHECK: i32 4, label %sw.bb5
; CHECK: ], !prof !1
sw.bb:
call void @func2(i32 %N) nounwind
br label %sw.epilog
sw.bb1:
call void @func4(i32 %N) nounwind
br label %sw.epilog
sw2:
;; Here "case 2" is invalidated if control is transferred through default case
;; of the first switch.
switch i32 %N, label %sw.epilog [
i32 2, label %sw.bb4
i32 4, label %sw.bb5
], !prof !3
sw.bb4:
call void @func6(i32 %N) nounwind
br label %sw.epilog
sw.bb5:
call void @func8(i32 %N) nounwind
br label %sw.epilog
sw.epilog:
ret void
}
PGO: preserve branch-weight metadata when merging two switches where the default target of the first switch is not the basic block the second switch is in (PredDefault != BB). llvm-svn: 163916
2012-09-15 01:29:56 +08:00
;; test3 - Merge two switches where PredDefault != BB.
define void @test3(i32 %M, i32 %N) nounwind uwtable {
entry:
%cmp = icmp sgt i32 %M, 2
br i1 %cmp, label %sw1, label %sw2
sw1:
switch i32 %N, label %sw.bb [
i32 2, label %sw2
i32 3, label %sw2
i32 1, label %sw.bb1
], !prof !4
; CHECK: test3
; CHECK: switch i32 %N, label %sw.bb
; CHECK: i32 1, label %sw.bb1
; CHECK: i32 3, label %sw.bb4
; CHECK: i32 2, label %sw.epilog
; CHECK: ], !prof !3
sw.bb:
call void @func2(i32 %N) nounwind
br label %sw.epilog
sw.bb1:
call void @func4(i32 %N) nounwind
br label %sw.epilog
sw2:
switch i32 %N, label %sw.epilog [
i32 3, label %sw.bb4
i32 4, label %sw.bb5
], !prof !5
sw.bb4:
call void @func6(i32 %N) nounwind
br label %sw.epilog
sw.bb5:
call void @func8(i32 %N) nounwind
br label %sw.epilog
sw.epilog:
ret void
}
SimplifyCFG: preserve branch-weight metadata when creating a new switch from a pair of switch/branch where both depend on the value of the same variable and the default case of the first switch/branch goes to the second switch/branch. Code clean up and fixed a few issues: 1> handling the case where some cases of the 2nd switch are invalidated 2> correctly calculate the weight for the 2nd switch when it is a conditional eq Testing case is modified from Alastair's original patch. llvm-svn: 163635
2012-09-12 01:43:35 +08:00
!0 = metadata !{metadata !"branch_weights", i32 64, i32 4}
!1 = metadata !{metadata !"branch_weights", i32 4, i32 64}
; CHECK: !0 = metadata !{metadata !"branch_weights", i32 256, i32 4352, i32 16}
!2 = metadata !{metadata !"branch_weights", i32 4, i32 4, i32 8}
!3 = metadata !{metadata !"branch_weights", i32 8, i32 8, i32 4}
; CHECK: !1 = metadata !{metadata !"branch_weights", i32 32, i32 48, i32 96, i32 16}
PGO: preserve branch-weight metadata when merging two switches where the default target of the first switch is not the basic block the second switch is in (PredDefault != BB). llvm-svn: 163916
2012-09-15 01:29:56 +08:00
!4 = metadata !{metadata !"branch_weights", i32 7, i32 6, i32 4, i32 3}
!5 = metadata !{metadata !"branch_weights", i32 17, i32 13, i32 9}
; CHECK: !3 = metadata !{metadata !"branch_weights", i32 7, i32 3, i32 4, i32 6}