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Add foreach_active iteration statement.

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Issue #298.
This commit is contained in:
Matt Pharr
2012-06-22 10:35:43 -07:00
parent ed13dd066b
commit b4a078e2f6
15 changed files with 644 additions and 279 deletions
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29
ctx.cpp
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@@ -89,12 +89,14 @@ struct CFInfo {
bool IsIf() { return type == If; }
bool IsLoop() { return type == Loop; }
bool IsForeach() { return (type == ForeachRegular ||
type == ForeachActive ||
type == ForeachUnique); }
bool IsSwitch() { return type == Switch; }
bool IsVarying() { return !isUniform; }
bool IsUniform() { return isUniform; }
enum CFType { If, Loop, ForeachRegular, ForeachUnique, Switch };
enum CFType { If, Loop, ForeachRegular, ForeachActive, ForeachUnique,
Switch };
CFType type;
bool isUniform;
llvm::BasicBlock *savedBreakTarget, *savedContinueTarget;
@@ -143,7 +145,7 @@ private:
CFInfo(CFType t, llvm::BasicBlock *bt, llvm::BasicBlock *ct,
llvm::Value *sb, llvm::Value *sc, llvm::Value *sm,
llvm::Value *lm) {
Assert(t == ForeachRegular || t == ForeachUnique);
Assert(t == ForeachRegular || t == ForeachActive || t == ForeachUnique);
type = t;
isUniform = false;
savedBreakTarget = bt;
@@ -190,6 +192,9 @@ CFInfo::GetForeach(FunctionEmitContext::ForeachType ft,
case FunctionEmitContext::FOREACH_REGULAR:
cfType = ForeachRegular;
break;
case FunctionEmitContext::FOREACH_ACTIVE:
cfType = ForeachActive;
break;
case FunctionEmitContext::FOREACH_UNIQUE:
cfType = ForeachUnique;
break;
@@ -744,6 +749,16 @@ FunctionEmitContext::Break(bool doCoherenceCheck) {
}
static bool
lEnclosingLoopIsForeachActive(const std::vector<CFInfo *> &controlFlowInfo) {
for (int i = (int)controlFlowInfo.size() - 1; i >= 0; --i) {
if (controlFlowInfo[i]->type == CFInfo::ForeachActive)
return true;
}
return false;
}
void
FunctionEmitContext::Continue(bool doCoherenceCheck) {
if (!continueTarget) {
@@ -753,12 +768,16 @@ FunctionEmitContext::Continue(bool doCoherenceCheck) {
}
AssertPos(currentPos, controlFlowInfo.size() > 0);
if (ifsInCFAllUniform(CFInfo::Loop)) {
if (ifsInCFAllUniform(CFInfo::Loop) ||
lEnclosingLoopIsForeachActive(controlFlowInfo)) {
// Similarly to 'break' statements, we can immediately jump to the
// continue target if we're only in 'uniform' control flow within
// loop or if we can tell that the mask is all on.
// loop or if we can tell that the mask is all on. Here, we can
// also jump if the enclosing loop is a 'foreach_active' loop, in
// which case we know that only a single program instance is
// executing.
AddInstrumentationPoint("continue: uniform CF, jumped");
if (ifsInCFAllUniform(CFInfo::Loop) && doCoherenceCheck)
if (doCoherenceCheck)
Warning(currentPos, "Coherent continue statement not necessary in "
"fully uniform control flow.");
BranchInst(continueTarget);