tail-merge-branch-weight.ll
1.56 KB
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; RUN: llc -mtriple=arm-apple-ios -print-machineinstrs=branch-folder \
; RUN: %s -o /dev/null 2>&1 | FileCheck %s
; Branch probability of tailed-merged block:
;
; p(L0_L1 -> L2) = p(entry -> L0) * p(L0 -> L2) + p(entry -> L1) * p(L1 -> L2)
; = 0.2 * 0.6 + 0.8 * 0.3 = 0.36
; p(L0_L1 -> L3) = p(entry -> L0) * p(L0 -> L3) + p(entry -> L1) * p(L1 -> L3)
; = 0.2 * 0.4 + 0.8 * 0.7 = 0.64
; CHECK: # Machine code for function test0:
; CHECK: successors: %bb.{{[0-9]+}}(0x1999999a), %bb.{{[0-9]+}}(0x66666666)
; CHECK: bb.{{[0-9]+}}{{[0-9a-zA-Z.]*}}:
; CHECK: bb.{{[0-9]+}}{{[0-9a-zA-Z.]*}}:
; CHECK: # End machine code for function test0.
define i32 @test0(i32 %n, i32 %m, i32* nocapture %a, i32* nocapture %b) {
entry:
%cmp = icmp sgt i32 %n, 0
br i1 %cmp, label %L0, label %L1, !prof !0
L0: ; preds = %entry
store i32 12, i32* %a, align 4
store i32 18, i32* %b, align 4
%cmp1 = icmp eq i32 %m, 8
br i1 %cmp1, label %L2, label %L3, !prof !1
L1: ; preds = %entry
store i32 14, i32* %a, align 4
store i32 18, i32* %b, align 4
%cmp3 = icmp eq i32 %m, 8
br i1 %cmp3, label %L2, label %L3, !prof !2
L2: ; preds = %L1, %L0
br label %L3
L3: ; preds = %L0, %L1, %L2
%retval.0 = phi i32 [ 100, %L2 ], [ 6, %L1 ], [ 6, %L0 ]
ret i32 %retval.0
}
!0 = !{!"branch_weights", i32 200, i32 800}
!1 = !{!"branch_weights", i32 600, i32 400}
!2 = !{!"branch_weights", i32 300, i32 700}