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Allow 'continue' statements in 'foreach' loops.

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This commit is contained in:
Matt Pharr
2011-12-03 09:31:02 -08:00
parent c3b55de1ad
commit a1c0b4f95a
17 changed files with 359 additions and 40 deletions
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99
ctx.cpp
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@@ -401,22 +401,26 @@ FunctionEmitContext::EndIf() {
// or continue statements (and breakLanesPtr and continueLanesPtr
// have their initial 'all off' values), so we don't need to check
// for that here.
if (breakLanesPtr != NULL) {
assert(continueLanesPtr != NULL);
if (continueLanesPtr != NULL) {
// We want to compute:
// newMask = (oldMask & ~(breakLanes | continueLanes))
llvm::Value *oldMask = GetInternalMask();
llvm::Value *breakLanes = LoadInst(breakLanesPtr, "break_lanes");
llvm::Value *continueLanes = LoadInst(continueLanesPtr,
"continue_lanes");
llvm::Value *breakOrContinueLanes =
BinaryOperator(llvm::Instruction::Or, breakLanes, continueLanes,
"break|continue_lanes");
llvm::Value *notBreakOrContinue = NotOperator(breakOrContinueLanes,
"!(break|continue)_lanes");
llvm::Value *bcLanes = continueLanes;
if (breakLanesPtr != NULL) {
// breakLanesPtr will be NULL if we're inside a 'foreach' loop
llvm::Value *breakLanes = LoadInst(breakLanesPtr, "break_lanes");
bcLanes = BinaryOperator(llvm::Instruction::Or, breakLanes,
continueLanes, "break|continue_lanes");
}
llvm::Value *notBreakOrContinue =
NotOperator(bcLanes, "!(break|continue)_lanes");
llvm::Value *newMask =
BinaryOperator(llvm::Instruction::And, oldMask, notBreakOrContinue,
"new_mask");
BinaryOperator(llvm::Instruction::And, oldMask,
notBreakOrContinue, "new_mask");
SetInternalMask(newMask);
}
}
@@ -477,15 +481,20 @@ FunctionEmitContext::EndLoop() {
void
FunctionEmitContext::StartForeach() {
FunctionEmitContext::StartForeach(llvm::BasicBlock *ct) {
// Store the current values of various loop-related state so that we
// can restore it when we exit this loop.
llvm::Value *oldMask = GetInternalMask();
controlFlowInfo.push_back(CFInfo::GetForeach(breakTarget, continueTarget, breakLanesPtr,
continueLanesPtr, oldMask, loopMask));
continueLanesPtr = breakLanesPtr = NULL;
controlFlowInfo.push_back(CFInfo::GetForeach(breakTarget, continueTarget,
breakLanesPtr, continueLanesPtr,
oldMask, loopMask));
breakLanesPtr = NULL;
breakTarget = NULL;
continueTarget = NULL;
continueLanesPtr = AllocaInst(LLVMTypes::MaskType, "foreach_continue_lanes");
StoreInst(LLVMMaskAllOff, continueLanesPtr);
continueTarget = ct;
loopMask = NULL;
}
@@ -526,7 +535,8 @@ FunctionEmitContext::restoreMaskGivenReturns(llvm::Value *oldMask) {
void
FunctionEmitContext::Break(bool doCoherenceCheck) {
if (breakTarget == NULL) {
Error(currentPos, "\"break\" statement is illegal outside of for/while/do loops.");
Error(currentPos, "\"break\" statement is illegal outside of "
"for/while/do loops.");
return;
}
@@ -576,7 +586,8 @@ FunctionEmitContext::Break(bool doCoherenceCheck) {
void
FunctionEmitContext::Continue(bool doCoherenceCheck) {
if (!continueTarget) {
Error(currentPos, "\"continue\" statement illegal outside of for/while/do loops.");
Error(currentPos, "\"continue\" statement illegal outside of "
"for/while/do/foreach loops.");
return;
}
@@ -586,8 +597,8 @@ FunctionEmitContext::Continue(bool doCoherenceCheck) {
// loop or if we can tell that the mask is all on.
AddInstrumentationPoint("continue: uniform CF, jumped");
if (ifsInLoopAllUniform() && doCoherenceCheck)
Warning(currentPos, "Coherent continue statement not necessary in fully uniform "
"control flow.");
Warning(currentPos, "Coherent continue statement not necessary in "
"fully uniform control flow.");
BranchInst(continueTarget);
bblock = NULL;
}
@@ -638,26 +649,40 @@ FunctionEmitContext::ifsInLoopAllUniform() const {
void
FunctionEmitContext::jumpIfAllLoopLanesAreDone(llvm::BasicBlock *target) {
// Check to see if (returned lanes | continued lanes | break lanes) is
// equal to the value of mask at the start of the loop iteration. If
// so, everyone is done and we can jump to the given target
llvm::Value *returned = LoadInst(returnedLanesPtr,
"returned_lanes");
llvm::Value *continued = LoadInst(continueLanesPtr,
"continue_lanes");
llvm::Value *breaked = LoadInst(breakLanesPtr, "break_lanes");
llvm::Value *returnedOrContinued = BinaryOperator(llvm::Instruction::Or,
returned, continued,
"returned|continued");
llvm::Value *returnedOrContinuedOrBreaked =
BinaryOperator(llvm::Instruction::Or, returnedOrContinued,
breaked, "returned|continued");
llvm::Value *allDone = NULL;
assert(continueLanesPtr != NULL);
if (breakLanesPtr == NULL) {
// In a foreach loop, break and return are illegal, and
// breakLanesPtr is NULL. In this case, the mask is guaranteed to
// be all on at the start of each iteration, so we only need to
// check if all lanes have continued..
llvm::Value *continued = LoadInst(continueLanesPtr,
"continue_lanes");
allDone = All(continued);
}
else {
// Check to see if (returned lanes | continued lanes | break lanes) is
// equal to the value of mask at the start of the loop iteration. If
// so, everyone is done and we can jump to the given target
llvm::Value *returned = LoadInst(returnedLanesPtr,
"returned_lanes");
llvm::Value *continued = LoadInst(continueLanesPtr,
"continue_lanes");
llvm::Value *breaked = LoadInst(breakLanesPtr, "break_lanes");
llvm::Value *returnedOrContinued = BinaryOperator(llvm::Instruction::Or,
returned, continued,
"returned|continued");
llvm::Value *returnedOrContinuedOrBreaked =
BinaryOperator(llvm::Instruction::Or, returnedOrContinued,
breaked, "returned|continued");
// Do we match the mask at loop entry?
allDone = MasksAllEqual(returnedOrContinuedOrBreaked, loopMask);
}
// Do we match the mask at loop entry?
llvm::Value *allRCB = MasksAllEqual(returnedOrContinuedOrBreaked, loopMask);
llvm::BasicBlock *bAll = CreateBasicBlock("all_continued_or_breaked");
llvm::BasicBlock *bNotAll = CreateBasicBlock("not_all_continued_or_breaked");
BranchInst(bAll, bNotAll, allRCB);
BranchInst(bAll, bNotAll, allDone);
// If so, have an extra basic block along the way to add
// instrumentation, if the user asked for it.