llvm/test/CodeGen/ARM/tail-opts.ll
Chandler Carruth 9e67db4af1 Flip the new block-placement pass to be on by default.
This is mostly to test the waters. I'd like to get results from FNT
build bots and other bots running on non-x86 platforms.

This feature has been pretty heavily tested over the last few months by
me, and it fixes several of the execution time regressions caused by the
inlining work by preventing inlining decisions from radically impacting
block layout.

I've seen very large improvements in yacr2 and ackermann benchmarks,
along with the expected noise across all of the benchmark suite whenever
code layout changes. I've analyzed all of the regressions and fixed
them, or found them to be impossible to fix. See my email to llvmdev for
more details.

I'd like for this to be in 3.1 as it complements the inliner changes,
but if any failures are showing up or anyone has concerns, it is just
a flag flip and so can be easily turned off.

I'm switching it on tonight to try and get at least one run through
various folks' performance suites in case SPEC or something else has
serious issues with it. I'll watch bots and revert if anything shows up.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154816 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-16 13:49:17 +00:00

68 lines
1.5 KiB
LLVM

; RUN: llc < %s -mtriple=arm-apple-darwin -relocation-model=dynamic-no-pic -mcpu=cortex-a8 -asm-verbose=false | FileCheck %s
declare void @bar(i32)
declare void @car(i32)
declare void @dar(i32)
declare void @ear(i32)
declare void @far(i32)
declare i1 @qux()
@GHJK = global i32 0
declare i8* @choose(i8*, i8*)
; BranchFolding should tail-duplicate the indirect jump to avoid
; redundant branching.
; CHECK: tail_duplicate_me:
; CHECK: qux
; CHECK: movw r{{[0-9]+}}, :lower16:_GHJK
; CHECK: movt r{{[0-9]+}}, :upper16:_GHJK
; CHECK: str r
; CHECK-NEXT: bx r
; CHECK: qux
; CHECK: movw r{{[0-9]+}}, :lower16:_GHJK
; CHECK: movt r{{[0-9]+}}, :upper16:_GHJK
; CHECK: str r
; CHECK-NEXT: bx r
; CHECK: movw r{{[0-9]+}}, :lower16:_GHJK
; CHECK: movt r{{[0-9]+}}, :upper16:_GHJK
; CHECK: str r
; CHECK-NEXT: bx r
define void @tail_duplicate_me() nounwind {
entry:
%a = call i1 @qux()
%c = call i8* @choose(i8* blockaddress(@tail_duplicate_me, %return),
i8* blockaddress(@tail_duplicate_me, %altret))
br i1 %a, label %A, label %next
next:
%b = call i1 @qux()
br i1 %b, label %B, label %C
A:
call void @bar(i32 0)
store i32 0, i32* @GHJK
br label %M
B:
call void @car(i32 1)
store i32 0, i32* @GHJK
br label %M
C:
call void @dar(i32 2)
store i32 0, i32* @GHJK
br label %M
M:
indirectbr i8* %c, [label %return, label %altret]
return:
call void @ear(i32 1000)
ret void
altret:
call void @far(i32 1001)
ret void
}