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Don't sink or hoist debug info instrinsics; it isn't useful. This also prevents LICM sinking from erasing debug intrinsics which don't dominate any exit block of the loop. 

rdar://9143943 .

llvm-svn: 132201
This commit is contained in:
Eli Friedman 2011-05-27 18:37:52 +00:00
parent bd04b74bb2
commit 942e1c10f6
1 changed files with 6 additions and 3 deletions
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9
llvm/lib/Transforms/Scalar/LICM.cpp
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@ -372,7 +372,11 @@ bool LICM::canSinkOrHoistInst(Instruction &I) {
return !pointerInvalidatedByLoop(LI->getOperand(0), Size,
LI->getMetadata(LLVMContext::MD_tbaa));
} else if (CallInst *CI = dyn_cast<CallInst>(&I)) {
// Handle obvious cases efficiently.
// Don't sink or hoist dbg info; it's legal, but not useful.
if (isa<DbgInfoIntrinsic>(I))
return false;
// Handle simple cases by querying alias analysis.
AliasAnalysis::ModRefBehavior Behavior = AA->getModRefBehavior(CI);
if (Behavior == AliasAnalysis::DoesNotAccessMemory)
return true;
@ -445,8 +449,7 @@ void LICM::sink(Instruction &I) {
// enough that we handle it as a special (more efficient) case. It is more
// efficient to handle because there are no PHI nodes that need to be placed.
if (ExitBlocks.size() == 1) {
if (!isa<DbgInfoIntrinsic>(I) &&
!DT->dominates(I.getParent(), ExitBlocks[0])) {
if (!DT->dominates(I.getParent(), ExitBlocks[0])) {
// Instruction is not used, just delete it.
CurAST->deleteValue(&I);
// If I has users in unreachable blocks, eliminate.