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llvm-project/llvm/test/CodeGen/Thumb2/cbnz.ll

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Thumb2: When applying branch optimizations, visit branches in reverse order. The order in which branches appear in ImmBranches is approximately their order within the function body. By visiting later branches first, we reduce the distance between earlier forward branches and their targets, making it more likely that the cbn?z optimization, which can only apply to forward branches, will succeed for those earlier branches. Differential Revision: http://reviews.llvm.org/D9185 llvm-svn: 235640
2015-04-24 04:31:35 +08:00
; RUN: llc -mtriple thumbv7-unknown-linux -o - %s | FileCheck %s
declare void @x()
declare void @y()
define void @f(i32 %x, i32 %y) {
; CHECK-LABEL: f:
; CHECK: cbnz
%p = icmp eq i32 %x, 0
br i1 %p, label %t, label %f
t:
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
CodeGen: Allow small copyable blocks to "break" the CFG. When choosing the best successor for a block, ordinarily we would have preferred a block that preserves the CFG unless there is a strong probability the other direction. For small blocks that can be duplicated we now skip that requirement as well, subject to some simple frequency calculations. Differential Revision: https://reviews.llvm.org/D28583 llvm-svn: 293716
2017-02-01 07:48:32 +08:00
; CHECK: cbz
Thumb2: When applying branch optimizations, visit branches in reverse order. The order in which branches appear in ImmBranches is approximately their order within the function body. By visiting later branches first, we reduce the distance between earlier forward branches and their targets, making it more likely that the cbn?z optimization, which can only apply to forward branches, will succeed for those earlier branches. Differential Revision: http://reviews.llvm.org/D9185 llvm-svn: 235640
2015-04-24 04:31:35 +08:00
%q = icmp eq i32 %y, 0
br i1 %q, label %t2, label %f
t2:
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
call void @x()
br label %f
f:
call void @y()
ret void
}