mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-10-07 05:55:44 +00:00
70b56056a1
BranchFolderPass was not correctly setting the basic block branch weights when tail-merging created or merged blocks. This patch recomutes the weights of tail-merged blocks using the following formula: branch_weight(merged block to successor j) = sum(block_frequency(bb) * branch_probability(bb -> j)) bb is a block that is in the set of merged blocks. <rdar://problem/16256423> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215135 91177308-0d34-0410-b5e6-96231b3b80d8
45 lines
1.6 KiB
LLVM
45 lines
1.6 KiB
LLVM
; 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 according to CFG: BB#{{[0-9]+}}(13) BB#{{[0-9]+}}(24)
|
|
; CHECK: BB#{{[0-9]+}}:
|
|
; CHECK: BB#{{[0-9]+}}:
|
|
; 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 = metadata !{metadata !"branch_weights", i32 200, i32 800}
|
|
!1 = metadata !{metadata !"branch_weights", i32 600, i32 400}
|
|
!2 = metadata !{metadata !"branch_weights", i32 300, i32 700}
|