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Revert r124462. There are a few big regressions that I need to fix first.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124478 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2011-01-28 07:12:38 +00:00
parent 07317f7d33
commit 1b5c0cb71d
10 changed files with 32 additions and 78 deletions
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11
lib/CodeGen/TailDuplication.cpp
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@@ -465,12 +465,9 @@ TailDuplicatePass::TailDuplicate(MachineBasicBlock *TailBB, MachineFunction &MF,
MaxDuplicateCount = TailDuplicateSize;
if (PreRegAlloc) {
if (TailBB->empty())
return false;
const TargetInstrDesc &TID = TailBB->back().getDesc();
// Pre-regalloc tail duplication hurts compile time and doesn't help
// much except for indirect branches and returns.
if (!TID.isIndirectBranch() && !TID.isReturn())
// Pre-regalloc tail duplication hurts compile time and doesn't help
// much except for indirect branches.
if (TailBB->empty() || !TailBB->back().getDesc().isIndirectBranch())
return false;
// If the target has hardware branch prediction that can handle indirect
// branches, duplicating them can often make them predictable when there
@@ -505,7 +502,7 @@ TailDuplicatePass::TailDuplicate(MachineBasicBlock *TailBB, MachineFunction &MF,
}
// Heuristically, don't tail-duplicate calls if it would expand code size,
// as it's less likely to be worth the extra cost.
if (InstrCount > 1 && (PreRegAlloc && HasCall))
if (InstrCount > 1 && HasCall)
return false;
DEBUG(dbgs() << "\n*** Tail-duplicating BB#" << TailBB->getNumber() << '\n');