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Add support for running SelectionDAG if FastISel fails. This is under 

a command-line option, so that the default behavior is an abort, which
is useful for exposing code that isn't supported yet.

llvm-svn: 55028
This commit is contained in:
Dan Gohman 2008-08-20 00:47:54 +00:00
parent a7e8c231ea
commit 847ebb90b8
1 changed files with 16 additions and 11 deletions
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21
llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
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@ -59,7 +59,10 @@ EnableLegalizeTypes("enable-legalize-types", cl::Hidden);
static cl::opt<bool>
EnableFastISel("fast-isel", cl::Hidden,
cl::desc("Enable the experimental \"fast\" instruction selector"));
static cl::opt<bool>
DisableFastISelAbort("fast-isel-no-abort", cl::Hidden,
cl::desc("Use the SelectionDAGISel when \"fast\" instruction "
"selection fails"));
#ifndef NDEBUG
static cl::opt<bool>
@ -5103,6 +5106,7 @@ void SelectionDAGISel::BuildSelectionDAG(SelectionDAG &DAG, BasicBlock *LLVMBB,
// landing pads, which also require special handling.
// For now, also exclude blocks with terminators that aren't
// unconditional branches.
BasicBlock::iterator Begin = LLVMBB->begin();
if (EnableFastISel &&
LLVMBB != &LLVMBB->getParent()->getEntryBlock() &&
!BB->isLandingPad() &&
@ -5110,19 +5114,20 @@ void SelectionDAGISel::BuildSelectionDAG(SelectionDAG &DAG, BasicBlock *LLVMBB,
cast<BranchInst>(LLVMBB->getTerminator())->isUnconditional()) {
if (FastISel *F = TLI.createFastISel(BB, &FuncInfo.MF,
TLI.getTargetMachine().getInstrInfo())) {
BasicBlock::iterator I =
F->SelectInstructions(LLVMBB->begin(), LLVMBB->end(), FuncInfo.ValueMap);
if (I == LLVMBB->end())
Begin = F->SelectInstructions(Begin, LLVMBB->end(), FuncInfo.ValueMap);
if (Begin == LLVMBB->end())
// The "fast" selector selected the entire block, so we're done.
return;
if (!DisableFastISelAbort) {
// The "fast" selector couldn't handle something and bailed.
// For the temporary purpose of debugging, just abort.
I->dump();
// For the purpose of debugging, just abort.
DEBUG(Begin->dump());
assert(0 && "FastISel didn't select the entire block");
abort();
}
}
}
// Lower any arguments needed in this block if this is the entry block.
if (LLVMBB == &LLVMBB->getParent()->getEntryBlock())
@ -5172,13 +5177,13 @@ void SelectionDAGISel::BuildSelectionDAG(SelectionDAG &DAG, BasicBlock *LLVMBB,
}
// Lower all of the non-terminator instructions.
for (BasicBlock::iterator I = LLVMBB->begin(), E = --LLVMBB->end();
for (BasicBlock::iterator I = Begin, E = --LLVMBB->end();
I != E; ++I)
SDL.visit(*I);
// Ensure that all instructions which are used outside of their defining
// blocks are available as virtual registers. Invoke is handled elsewhere.
for (BasicBlock::iterator I = LLVMBB->begin(), E = LLVMBB->end(); I != E;++I)
for (BasicBlock::iterator I = Begin, E = LLVMBB->end(); I != E;++I)
if (!I->use_empty() && !isa<PHINode>(I) && !isa<InvokeInst>(I)) {
DenseMap<const Value*, unsigned>::iterator VMI =FuncInfo.ValueMap.find(I);
if (VMI != FuncInfo.ValueMap.end())