Remove experimental options to control machine block placement.

[chandlerc]

Looks good.

[djasper]

Submitted as r229648.

lib/CodeGen/MachineBlockPlacement.cpp

 STATISTIC(UncondBranchTakenFreq,
           "Potential frequency of taking unconditional branches");
 
 static cl::opt<unsigned> AlignAllBlock("align-all-blocks",
                                        cl::desc("Force the alignment of all "
                                                 "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",
               cl::desc("Block frequency percentage a loop exit block needs "
                        "over the original exit to be considered the new exit."),
               cl::init(0), cl::Hidden);
 
 namespace {
for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(),
     // any CFG constraints.
     if (SuccChain.LoopPredecessors != 0) {
       if (SuccProb < HotProb) {
         DEBUG(dbgs() << "    " << getBlockName(*SI) << " -> " << SuccProb
                      << " (prob) (CFG conflict)\n");
         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");
-          continue;
-        }
-      }
-    }
+          MBFI->getBlockFreq(BB) * SuccProb * HotProb.getCompl();
 
     DEBUG(dbgs() << "    " << getBlockName(*SI) << " -> " << SuccProb
                  << " (prob)"
                  << (SuccChain.LoopPredecessors != 0 ? " (CFG break)" : "")
                  << "\n");
     if (BestSucc && BestWeight >= SuccWeight)
       continue;
     BestSucc = *SI;

test/CodeGen/X86/code_placement_bad_cfg_check.ll

-; 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()