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Remove experimental options to control machine block placement. 

This reverts r226034. Benchmarking with those flags has not revealed
anything interesting.

llvm-svn: 229648
This commit is contained in:
Daniel Jasper 2015-02-18 08:18:07 +00:00
parent 6ddd998589
commit 4d7b04384e
2 changed files with 20 additions and 147 deletions
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55
llvm/lib/CodeGen/MachineBlockPlacement.cpp
View File

@ -60,17 +60,6 @@ static cl::opt<unsigned> AlignAllBlock("align-all-blocks",
"blocks in the function."),
cl::init(0), cl::Hidden);
static cl::opt<bool> OnlyHotBadCFGConflictCheck(
"only-hot-bad-cfg-conflict-check",
cl::desc("Only check that a hot successor doesn't have a hot predecessor."),
cl::init(false), cl::Hidden);
static cl::opt<bool> NoBadCFGConflictCheck(
"no-bad-cfg-conflict-check",
cl::desc("Don't check whether a hot successor has a more important "
"predecessor."),
cl::init(false), cl::Hidden);
// FIXME: Find a good default for this flag and remove the flag.
static cl::opt<unsigned>
ExitBlockBias("block-placement-exit-block-bias",
@ -385,33 +374,29 @@ MachineBasicBlock *MachineBlockPlacement::selectBestSuccessor(
continue;
}
if (!NoBadCFGConflictCheck) {
// Make sure that a hot successor doesn't have a globally more
// important predecessor.
BlockFrequency CandidateEdgeFreq =
OnlyHotBadCFGConflictCheck
? MBFI->getBlockFreq(BB) * SuccProb
: MBFI->getBlockFreq(BB) * SuccProb * HotProb.getCompl();
bool BadCFGConflict = false;
for (MachineBasicBlock::pred_iterator PI = (*SI)->pred_begin(),
PE = (*SI)->pred_end();
PI != PE; ++PI) {
if (*PI == *SI || (BlockFilter && !BlockFilter->count(*PI)) ||
BlockToChain[*PI] == &Chain)
continue;
BlockFrequency PredEdgeFreq =
MBFI->getBlockFreq(*PI) * MBPI->getEdgeProbability(*PI, *SI);
if (PredEdgeFreq >= CandidateEdgeFreq) {
BadCFGConflict = true;
break;
}
}
if (BadCFGConflict) {
DEBUG(dbgs() << " " << getBlockName(*SI) << " -> " << SuccProb
<< " (prob) (non-cold CFG conflict)\n");
// Make sure that a hot successor doesn't have a globally more
// important predecessor.
BlockFrequency CandidateEdgeFreq =
MBFI->getBlockFreq(BB) * SuccProb * HotProb.getCompl();
bool BadCFGConflict = false;
for (MachineBasicBlock::pred_iterator PI = (*SI)->pred_begin(),
PE = (*SI)->pred_end();
PI != PE; ++PI) {
if (*PI == *SI || (BlockFilter && !BlockFilter->count(*PI)) ||
BlockToChain[*PI] == &Chain)
continue;
BlockFrequency PredEdgeFreq =
MBFI->getBlockFreq(*PI) * MBPI->getEdgeProbability(*PI, *SI);
if (PredEdgeFreq >= CandidateEdgeFreq) {
BadCFGConflict = true;
break;
}
}
if (BadCFGConflict) {
DEBUG(dbgs() << " " << getBlockName(*SI) << " -> " << SuccProb
<< " (prob) (non-cold CFG conflict)\n");
continue;
}
}
DEBUG(dbgs() << " " << getBlockName(*SI) << " -> " << SuccProb

112
llvm/test/CodeGen/X86/code_placement_bad_cfg_check.ll
View File

@ -1,112 +0,0 @@
; RUN: llc -mcpu=corei7 -mtriple=x86_64-linux < %s | FileCheck %s -check-prefix=CHECK-BAD-CFG
; RUN: llc -mcpu=corei7 -mtriple=x86_64-linux -no-bad-cfg-conflict-check < %s | FileCheck %s -check-prefix=CHECK-NO-BAD-CFG
; RUN: llc -mcpu=corei7 -mtriple=x86_64-linux -only-hot-bad-cfg-conflict-check < %s | FileCheck %s -check-prefix=CHECK-HOT-BAD-CFG
define void @foo(i32 %t) {
; Test that we lift the call to 'c' up to immediately follow the call to 'b'
; when we disable the cfg conflict check.
;
; CHECK-BAD-CFG-LABEL: foo:
; CHECK-BAD-CFG: callq b
; CHECK-BAD-CFG: callq a
; CHECK-BAD-CFG: callq c
;
; CHECK-NO-BAD-CFG-LABEL: foo:
; CHECK-NO-BAD-CFG: callq b
; CHECK-NO-BAD-CFG: callq c
; CHECK-NO-BAD-CFG: callq a
;
; CHECK-HOT-BAD-CFG-LABEL: foo:
; CHECK-HOT-BAD-CFG: callq b
; CHECK-HOT-BAD-CFG: callq c
; CHECK-HOT-BAD-CFG: callq a
entry:
%cmp = icmp eq i32 %t, 0
br i1 %cmp, label %if.then, label %if.else
if.then:
call void @a()
br label %if.end
if.else:
call void @b()
br label %if.end
if.end:
call void @c()
ret void
}
define void @bar(i32 %t1, i32 %t2, i32 %t3) {
; Test that we lift the call to 'c' up to immediately follow the call to 'b'
; when we disable the cfg conflict check.
;
; CHECK-BAD-CFG-LABEL: bar:
; CHECK-BAD-CFG: callq a
; CHECK-BAD-CFG: callq c
; CHECK-BAD-CFG: callq d
; CHECK-BAD-CFG: callq f
; CHECK-BAD-CFG: callq b
; CHECK-BAD-CFG: callq e
; CHECK-BAD-CFG: callq g
;
; CHECK-NO-BAD-CFG-LABEL: bar:
; CHECK-NO-BAD-CFG: callq a
; CHECK-NO-BAD-CFG: callq c
; CHECK-NO-BAD-CFG: callq g
; CHECK-NO-BAD-CFG: callq d
; CHECK-NO-BAD-CFG: callq f
; CHECK-NO-BAD-CFG: callq b
; CHECK-NO-BAD-CFG: callq e
;
; CHECK-HOT-BAD-CFG-LABEL: bar:
; CHECK-HOT-BAD-CFG: callq a
; CHECK-HOT-BAD-CFG: callq c
; CHECK-HOT-BAD-CFG: callq d
; CHECK-HOT-BAD-CFG: callq f
; CHECK-HOT-BAD-CFG: callq g
; CHECK-HOT-BAD-CFG: callq b
; CHECK-HOT-BAD-CFG: callq e
entry:
br i1 undef, label %if1.then, label %if1.else
if1.then:
call void @a()
%cmp2 = icmp eq i32 %t2, 0
br i1 %cmp2, label %if2.then, label %if2.else
if2.then:
call void @b()
br label %if.end
if2.else:
call void @c()
br label %if.end
if1.else:
call void @d()
%cmp3 = icmp eq i32 %t3, 0
br i1 %cmp3, label %if3.then, label %if3.else
if3.then:
call void @e()
br label %if.end
if3.else:
call void @f()
br label %if.end
if.end:
call void @g()
ret void
}
declare void @a()
declare void @b()
declare void @c()
declare void @d()
declare void @e()
declare void @f()
declare void @g()