[llvm] r246810 - [RewriteStatepointsForGC] Extract common code, comment, and fix a build warning [NFC]
Philip Reames via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 3 14:57:41 PDT 2015
Author: reames
Date: Thu Sep 3 16:57:40 2015
New Revision: 246810
URL: http://llvm.org/viewvc/llvm-project?rev=246810&view=rev
Log:
[RewriteStatepointsForGC] Extract common code, comment, and fix a build warning [NFC]
Modified:
llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp?rev=246810&r1=246809&r2=246810&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp Thu Sep 3 16:57:40 2015
@@ -435,7 +435,7 @@ static BaseDefiningValueResult findBaseD
// Due to inheritance, this must be _after_ the global variable and undef
// checks
- if (Constant *Con = dyn_cast<Constant>(I)) {
+ if (isa<Constant>(I)) {
assert(!isa<GlobalVariable>(I) && !isa<UndefValue>(I) &&
"order of checks wrong!");
// Note: Finding a constant base for something marked for relocation
@@ -446,7 +446,7 @@ static BaseDefiningValueResult findBaseD
// off a potentially null value and have proven it null. We also use
// null pointers in dead paths of relocation phis (which we might later
// want to find a base pointer for).
- assert(isa<ConstantPointerNull>(Con) &&
+ assert(isa<ConstantPointerNull>(I) &&
"null is the only case which makes sense");
return BaseDefiningValueResult(I, true);
}
@@ -946,6 +946,34 @@ static Value *findBasePointer(Value *I,
states[I] = BDVState(BDVState::Conflict, BaseInst);
}
+ // Returns a instruction which produces the base pointer for a given
+ // instruction. The instruction is assumed to be an input to one of the BDVs
+ // seen in the inference algorithm above. As such, we must either already
+ // know it's base defining value is a base, or have inserted a new
+ // instruction to propagate the base of it's BDV and have entered that newly
+ // introduced instruction into the state table. In either case, we are
+ // assured to be able to determine an instruction which produces it's base
+ // pointer.
+ auto getBaseForInput = [&](Value *Input, Instruction *InsertPt) {
+ Value *BDV = findBaseOrBDV(Input, cache);
+ Value *Base = nullptr;
+ if (isKnownBaseResult(BDV)) {
+ Base = BDV;
+ } else {
+ // Either conflict or base.
+ assert(states.count(BDV));
+ Base = states[BDV].getBase();
+ }
+ assert(Base && "can't be null");
+ // The cast is needed since base traversal may strip away bitcasts
+ if (Base->getType() != Input->getType() &&
+ InsertPt) {
+ Base = new BitCastInst(Base, Input->getType(), "cast",
+ InsertPt);
+ }
+ return Base;
+ };
+
// Fixup all the inputs of the new PHIs
for (auto Pair : states) {
Instruction *v = cast<Instruction>(Pair.first);
@@ -976,15 +1004,9 @@ static Value *findBasePointer(Value *I,
if (blockIndex != -1) {
Value *oldBase = basephi->getIncomingValue(blockIndex);
basephi->addIncoming(oldBase, InBB);
+
#ifndef NDEBUG
- Value *base = findBaseOrBDV(InVal, cache);
- if (!isKnownBaseResult(base)) {
- // Either conflict or base.
- assert(states.count(base));
- base = states[base].getBase();
- assert(base != nullptr && "unknown BDVState!");
- }
-
+ Value *Base = getBaseForInput(InVal, nullptr);
// In essence this assert states: the only way two
// values incoming from the same basic block may be
// different is by being different bitcasts of the same
@@ -992,65 +1014,36 @@ static Value *findBasePointer(Value *I,
// findBaseOrBDV to return an llvm::Value of the correct
// type (and still remain pure). This will remove the
// need to add bitcasts.
- assert(base->stripPointerCasts() == oldBase->stripPointerCasts() &&
+ assert(Base->stripPointerCasts() == oldBase->stripPointerCasts() &&
"sanity -- findBaseOrBDV should be pure!");
#endif
continue;
}
- // Find either the defining value for the PHI or the normal base for
- // a non-phi node
- Value *base = findBaseOrBDV(InVal, cache);
- if (!isKnownBaseResult(base)) {
- // Either conflict or base.
- assert(states.count(base));
- base = states[base].getBase();
- assert(base != nullptr && "unknown BDVState!");
- }
- assert(base && "can't be null");
- // Must use original input BB since base may not be Instruction
- // The cast is needed since base traversal may strip away bitcasts
- if (base->getType() != basephi->getType()) {
- base = new BitCastInst(base, basephi->getType(), "cast",
- InBB->getTerminator());
- }
- basephi->addIncoming(base, InBB);
+ // Find the instruction which produces the base for each input. We may
+ // need to insert a bitcast in the incoming block.
+ // TODO: Need to split critical edges if insertion is needed
+ Value *Base = getBaseForInput(InVal, InBB->getTerminator());
+ basephi->addIncoming(Base, InBB);
}
assert(basephi->getNumIncomingValues() == NumPHIValues);
- } else if (SelectInst *basesel = dyn_cast<SelectInst>(state.getBase())) {
- SelectInst *sel = cast<SelectInst>(v);
+ } else if (SelectInst *BaseSel = dyn_cast<SelectInst>(state.getBase())) {
+ SelectInst *Sel = cast<SelectInst>(v);
// Operand 1 & 2 are true, false path respectively. TODO: refactor to
// something more safe and less hacky.
for (int i = 1; i <= 2; i++) {
- Value *InVal = sel->getOperand(i);
- // Find either the defining value for the PHI or the normal base for
- // a non-phi node
- Value *base = findBaseOrBDV(InVal, cache);
- if (!isKnownBaseResult(base)) {
- // Either conflict or base.
- assert(states.count(base));
- base = states[base].getBase();
- assert(base != nullptr && "unknown BDVState!");
- }
- assert(base && "can't be null");
- // Must use original input BB since base may not be Instruction
- // The cast is needed since base traversal may strip away bitcasts
- if (base->getType() != basesel->getType()) {
- base = new BitCastInst(base, basesel->getType(), "cast", basesel);
- }
- basesel->setOperand(i, base);
+ Value *InVal = Sel->getOperand(i);
+ // Find the instruction which produces the base for each input. We may
+ // need to insert a bitcast.
+ Value *Base = getBaseForInput(InVal, BaseSel);
+ BaseSel->setOperand(i, Base);
}
} else {
auto *BaseEE = cast<ExtractElementInst>(state.getBase());
Value *InVal = cast<ExtractElementInst>(v)->getVectorOperand();
- Value *Base = findBaseOrBDV(InVal, cache);
- if (!isKnownBaseResult(Base)) {
- // Either conflict or base.
- assert(states.count(Base));
- Base = states[Base].getBase();
- assert(Base != nullptr && "unknown BDVState!");
- }
- assert(Base && "can't be null");
+ // Find the instruction which produces the base for each input. We may
+ // need to insert a bitcast.
+ Value *Base = getBaseForInput(InVal, BaseEE);
BaseEE->setOperand(0, Base);
}
}
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