llvm/test/CodeGen/X86/switch-bt.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

102 lines
2.5 KiB
LLVM

; RUN: llc -march=x86-64 -asm-verbose=false < %s | FileCheck %s
; This switch should use bit tests, and the third bit test case is just
; testing for one possible value, so it doesn't need a bt.
; CHECK: movabsq $2305843009482129440, %r
; CHECK-NEXT: btq %rax, %r
; CHECK-NEXT: jae
; CHECK: movl $671088640, %e
; CHECK-NEXT: btq %rax, %r
; CHECK-NEXT: jae
; CHECK: testq %rax, %r
; CHECK-NEXT: j
define void @test(i8* %l) nounwind {
entry:
%l.addr = alloca i8*, align 8 ; <i8**> [#uses=2]
store i8* %l, i8** %l.addr
%tmp = load i8** %l.addr ; <i8*> [#uses=1]
%tmp1 = load i8* %tmp ; <i8> [#uses=1]
%conv = sext i8 %tmp1 to i32 ; <i32> [#uses=1]
switch i32 %conv, label %sw.default [
i32 62, label %sw.bb
i32 60, label %sw.bb
i32 38, label %sw.bb2
i32 94, label %sw.bb2
i32 61, label %sw.bb2
i32 33, label %sw.bb4
]
sw.bb: ; preds = %entry, %entry
call void @foo(i32 0)
br label %sw.epilog
sw.bb2: ; preds = %entry, %entry, %entry
call void @foo(i32 1)
br label %sw.epilog
sw.bb4: ; preds = %entry
call void @foo(i32 3)
br label %sw.epilog
sw.default: ; preds = %entry
call void @foo(i32 97)
br label %sw.epilog
sw.epilog: ; preds = %sw.default, %sw.bb4, %sw.bb2, %sw.bb
ret void
}
declare void @foo(i32)
; Don't zero extend the test operands to pointer type if it can be avoided.
; rdar://8781238
define void @test2(i32 %x) nounwind ssp {
; CHECK: test2:
; CHECK: cmpl $6
; CHECK: ja
; CHECK-NEXT: movl $91
; CHECK-NOT: movl
; CHECK-NEXT: btl
; CHECK-NEXT: jae
entry:
switch i32 %x, label %if.end [
i32 6, label %if.then
i32 4, label %if.then
i32 3, label %if.then
i32 1, label %if.then
i32 0, label %if.then
]
if.then: ; preds = %entry, %entry, %entry, %entry, %entry
tail call void @bar() nounwind
ret void
if.end: ; preds = %entry
ret void
}
declare void @bar()
define void @test3(i32 %x) nounwind {
; CHECK: test3:
; CHECK: cmpl $5
; CHECK: ja
; CHECK: cmpl $4
; CHECK: je
switch i32 %x, label %if.end [
i32 0, label %if.then
i32 1, label %if.then
i32 2, label %if.then
i32 3, label %if.then
i32 5, label %if.then
]
if.then:
tail call void @bar() nounwind
ret void
if.end:
ret void
}