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Make block placement deterministic 

We fail to produce bit-to-bit matching stage2 and stage3 compiler in PGO
bootstrap build. The reason is because LoopBlockSet is of SmallPtrSet type
whose iterating order depends on the pointer value.

This patch fixes this issue by changing to use SmallSetVector.

Differential Revision: http://reviews.llvm.org/D26634

llvm-svn: 287148
This commit is contained in:
Rong Xu 2016-11-16 20:50:06 +00:00
parent 80baf69cb5
commit 66827427e1
1 changed files with 3 additions and 3 deletions
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6
llvm/lib/CodeGen/MachineBlockPlacement.cpp
View File

@ -264,7 +264,7 @@ public:
namespace {
class MachineBlockPlacement : public MachineFunctionPass {
/// \brief A typedef for a block filter set.
typedef SmallPtrSet<MachineBasicBlock *, 16> BlockFilterSet;
typedef SmallSetVector<MachineBasicBlock *, 16> BlockFilterSet;
/// \brief work lists of blocks that are ready to be laid out
SmallVector<MachineBasicBlock *, 16> BlockWorkList;
@ -1512,7 +1512,7 @@ void MachineBlockPlacement::buildLoopChains(MachineLoop &L) {
}
for (MachineBasicBlock *ChainBB : LoopChain) {
dbgs() << " ... " << getBlockName(ChainBB) << "\n";
if (!LoopBlockSet.erase(ChainBB)) {
if (!LoopBlockSet.remove(ChainBB)) {
// We don't mark the loop as bad here because there are real situations
// where this can occur. For example, with an unanalyzable fallthrough
// from a loop block to a non-loop block or vice versa.
@ -1928,7 +1928,7 @@ bool MachineBlockPlacement::maybeTailDuplicateBlock(
// Handle the filter set
if (BlockFilter) {
BlockFilter->erase(RemBB);
BlockFilter->remove(RemBB);
}
// Remove the block from loop info.