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In the pre-RA scheduler, maintain cmp+br proximity.

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This is done by pushing physical register definitions close to their
use, which happens to handle flag definitions if they're not glued to
the branch. This seems to be generally a good thing though, so I
didn't need to add a target hook yet.

The primary motivation is to generate code closer to what people
expect and rule out missed opportunity from enabling macro-op
fusion. As a side benefit, we get several 2-5% gains on x86
benchmarks. There is one regression:
SingleSource/Benchmarks/Shootout/lists slows down be -10%. But this is
an independent scheduler bug that will be tracked separately.
See rdar://problem/9283108.

Incidentally, pre-RA scheduling is only half the solution. Fixing the
later passes is tracked by:
<rdar://problem/8932804> [pre-RA-sched] on x86, attempt to schedule CMP/TEST adjacent with condition jump

Fixes:
<rdar://problem/9262453> Scheduler unnecessary break of cmp/jump fusion


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129508 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick
2011-04-14 05:15:06 +00:00
parent b57b06647e
commit 12f0dc6bb5
8 changed files with 139 additions and 25 deletions
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65
test/CodeGen/X86/2011-04-13-SchedCmpJmp.ll Normal file
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@@ -0,0 +1,65 @@
; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=yonah | FileCheck %s
; Reduced from JavaScriptCore
%"class.JSC::CodeLocationCall" = type { [8 x i8] }
%"class.JSC::JSGlobalData" = type { [4 x i8] }
%"class.JSC::FunctionPtr" = type { i8* }
%"class.JSC::Structure" = type { [4 x i8] }
%"class.JSC::UString" = type { i8* }
%"class.JSC::JSString" = type { [16 x i8], i32, %"class.JSC::UString", i32 }
declare hidden fastcc void @_ZN3JSCL23returnToThrowTrampolineEPNS_12JSGlobalDataENS_16ReturnAddressPtrERS2_(%"class.JSC::JSGlobalData"* nocapture, i8*, %"class.JSC::FunctionPtr"* nocapture) nounwind noinline ssp
; Avoid hoisting the test above loads or copies
; CHECK: %entry
; CHECK: cmpq
; CHECK-NOT: mov
; CHECK: jb
define i32 @cti_op_eq(i8** nocapture %args) nounwind ssp {
entry:
%0 = load i8** null, align 8
%tmp13 = bitcast i8* %0 to %"class.JSC::CodeLocationCall"*
%tobool.i.i.i = icmp ugt i8* undef, inttoptr (i64 281474976710655 to i8*)
%or.cond.i = and i1 %tobool.i.i.i, undef
br i1 %or.cond.i, label %if.then.i, label %if.end.i
if.then.i: ; preds = %entry
br i1 undef, label %if.then.i.i.i, label %_ZN3JSC7JSValue19equalSlowCaseInlineEPNS_9ExecStateES0_S0_.exit
if.then.i.i.i: ; preds = %if.then.i
%conv.i.i.i.i = trunc i64 undef to i32
br label %_ZN3JSC7JSValue19equalSlowCaseInlineEPNS_9ExecStateES0_S0_.exit
if.end.i: ; preds = %entry
br i1 undef, label %land.rhs.i121.i, label %_ZNK3JSC7JSValue8isStringEv.exit122.i
land.rhs.i121.i: ; preds = %if.end.i
%tmp.i.i117.i = load %"class.JSC::Structure"** undef, align 8
br label %_ZNK3JSC7JSValue8isStringEv.exit122.i
_ZNK3JSC7JSValue8isStringEv.exit122.i: ; preds = %land.rhs.i121.i, %if.end.i
%brmerge.i = or i1 undef, false
%or.cond = or i1 false, %brmerge.i
br i1 %or.cond, label %_ZN3JSC7JSValue19equalSlowCaseInlineEPNS_9ExecStateES0_S0_.exit, label %if.then.i92.i
if.then.i92.i: ; preds = %_ZNK3JSC7JSValue8isStringEv.exit122.i
tail call void @_ZNK3JSC8JSString11resolveRopeEPNS_9ExecStateE(%"class.JSC::JSString"* undef, %"class.JSC::CodeLocationCall"* %tmp13) nounwind
unreachable
_ZN3JSC7JSValue19equalSlowCaseInlineEPNS_9ExecStateES0_S0_.exit: ; preds = %_ZNK3JSC7JSValue8isStringEv.exit122.i, %if.then.i.i.i, %if.then.i
%1 = load i8** undef, align 8
br i1 undef, label %do.end39, label %do.body27
do.body27: ; preds = %_ZN3JSC7JSValue19equalSlowCaseInlineEPNS_9ExecStateES0_S0_.exit
%tmp30 = bitcast i8* %1 to %"class.JSC::JSGlobalData"*
%2 = getelementptr inbounds i8** %args, i64 -1
%3 = bitcast i8** %2 to %"class.JSC::FunctionPtr"*
tail call fastcc void @_ZN3JSCL23returnToThrowTrampolineEPNS_12JSGlobalDataENS_16ReturnAddressPtrERS2_(%"class.JSC::JSGlobalData"* %tmp30, i8* undef, %"class.JSC::FunctionPtr"* %3)
unreachable
do.end39: ; preds = %_ZN3JSC7JSValue19equalSlowCaseInlineEPNS_9ExecStateES0_S0_.exit
ret i32 undef
}
declare void @_ZNK3JSC8JSString11resolveRopeEPNS_9ExecStateE(%"class.JSC::JSString"*, %"class.JSC::CodeLocationCall"*)

1
test/CodeGen/X86/lsr-loop-exit-cond.ll
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@@ -1,4 +1,3 @@
; XFAIL: *
; RUN: llc -march=x86-64 < %s | FileCheck %s
; CHECK: decq

3
test/CodeGen/X86/pr2659.ll
View File

@@ -18,7 +18,8 @@ forcond.preheader: ; preds = %entry
; CHECK: movl $1
; CHECK-NOT: xorl
; CHECK-NOT: movl
; CHECK-NEXT: je
; CHECK-NOT: LBB
; CHECK: je
ifthen: ; preds = %entry
ret i32 0

6
test/CodeGen/X86/tail-opts.ll
View File

@@ -109,15 +109,15 @@ altret:
; CHECK: dont_merge_oddly:
; CHECK-NOT: ret
; CHECK: ucomiss %xmm1, %xmm2
; CHECK: ucomiss %xmm{{[0-2]}}, %xmm{{[0-2]}}
; CHECK-NEXT: jbe .LBB2_3
; CHECK-NEXT: ucomiss %xmm0, %xmm1
; CHECK-NEXT: ucomiss %xmm{{[0-2]}}, %xmm{{[0-2]}}
; CHECK-NEXT: ja .LBB2_4
; CHECK-NEXT: .LBB2_2:
; CHECK-NEXT: movb $1, %al
; CHECK-NEXT: ret
; CHECK-NEXT: .LBB2_3:
; CHECK-NEXT: ucomiss %xmm0, %xmm2
; CHECK-NEXT: ucomiss %xmm{{[0-2]}}, %xmm{{[0-2]}}
; CHECK-NEXT: jbe .LBB2_2
; CHECK-NEXT: .LBB2_4:
; CHECK-NEXT: xorb %al, %al

8
test/CodeGen/X86/test-nofold.ll
View File

@@ -2,10 +2,10 @@
; rdar://5752025
; We want:
; CHECK: movl 4(%esp), %ecx
; CHECK-NEXT: andl $15, %ecx
; CHECK-NEXT: movl $42, %eax
; CHECK-NEXT: cmovel %ecx, %eax
; CHECK: movl $42, %ecx
; CHECK-NEXT: movl 4(%esp), %eax
; CHECK-NEXT: andl $15, %eax
; CHECK-NEXT: cmovnel %ecx, %eax
; CHECK-NEXT: ret
;
; We don't want: