Merging r195317:
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r195317 | probinson | 2013-11-20 22:33:32 -0800 (Wed, 20 Nov 2013) | 4 lines
Teach ISel not to optimize 'optnone' functions.
Based on work by Andrea Di Biagio.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_34@195321 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 8bf8756..1372169 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -223,6 +223,39 @@
namespace llvm {
//===--------------------------------------------------------------------===//
+ /// \brief This struct is used by SelectionDAGISel to temporarily override
+ /// the optimization level on a per-function basis.
+ class OptLevelChanger {
+ SelectionDAGISel &IS;
+ CodeGenOpt::Level SavedOptLevel;
+
+ public:
+ OptLevelChanger(SelectionDAGISel &ISel,
+ CodeGenOpt::Level NewOptLevel) : IS(ISel) {
+ SavedOptLevel = IS.OptLevel;
+ if (NewOptLevel == SavedOptLevel)
+ return;
+ IS.OptLevel = NewOptLevel;
+ IS.TM.setOptLevel(NewOptLevel);
+ DEBUG(dbgs() << "\nChanging optimization level for Function "
+ << IS.MF->getFunction()->getName() << "\n");
+ DEBUG(dbgs() << "\tBefore: -O" << SavedOptLevel
+ << " ; After: -O" << NewOptLevel << "\n");
+ }
+
+ ~OptLevelChanger() {
+ if (IS.OptLevel == SavedOptLevel)
+ return;
+ DEBUG(dbgs() << "\nRestoring optimization level for Function "
+ << IS.MF->getFunction()->getName() << "\n");
+ DEBUG(dbgs() << "\tBefore: -O" << IS.OptLevel
+ << " ; After: -O" << SavedOptLevel << "\n");
+ IS.OptLevel = SavedOptLevel;
+ IS.TM.setOptLevel(SavedOptLevel);
+ }
+ };
+
+ //===--------------------------------------------------------------------===//
/// createDefaultScheduler - This creates an instruction scheduler appropriate
/// for the target.
ScheduleDAGSDNodes* createDefaultScheduler(SelectionDAGISel *IS,
@@ -369,6 +402,12 @@
ST.resetSubtargetFeatures(MF);
TM.resetTargetOptions(MF);
+ // Reset OptLevel to None for optnone functions.
+ CodeGenOpt::Level NewOptLevel = OptLevel;
+ if (Fn.hasFnAttribute(Attribute::OptimizeNone))
+ NewOptLevel = CodeGenOpt::None;
+ OptLevelChanger OLC(*this, NewOptLevel);
+
DEBUG(dbgs() << "\n\n\n=== " << Fn.getName() << "\n");
SplitCriticalSideEffectEdges(const_cast<Function&>(Fn), this);
@@ -946,7 +985,7 @@
void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
// Initialize the Fast-ISel state, if needed.
FastISel *FastIS = 0;
- if (TM.Options.EnableFastISel)
+ if (TM.Options.EnableFastISel || Fn.hasFnAttribute(Attribute::OptimizeNone))
FastIS = getTargetLowering()->createFastISel(*FuncInfo, LibInfo);
// Iterate over all basic blocks in the function.