[llvm] r181160 - Teach if-converter to avoid removing BBs whose addresses are takne. rdar://13782395
Evan Cheng
evan.cheng at apple.com
Sun May 5 11:03:49 PDT 2013
Author: evancheng
Date: Sun May 5 13:03:49 2013
New Revision: 181160
URL: http://llvm.org/viewvc/llvm-project?rev=181160&view=rev
Log:
Teach if-converter to avoid removing BBs whose addresses are takne. rdar://13782395
Modified:
llvm/trunk/lib/CodeGen/IfConversion.cpp
Modified: llvm/trunk/lib/CodeGen/IfConversion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/IfConversion.cpp?rev=181160&r1=181159&r2=181160&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/IfConversion.cpp (original)
+++ llvm/trunk/lib/CodeGen/IfConversion.cpp Sun May 5 13:03:49 2013
@@ -1039,6 +1039,10 @@ bool IfConverter::IfConvertSimple(BBInfo
return false;
}
+ if (CvtBBI->BB->hasAddressTaken())
+ // Conservatively abort if-conversion if BB's address is taken.
+ return false;
+
if (Kind == ICSimpleFalse)
if (TII->ReverseBranchCondition(Cond))
llvm_unreachable("Unable to reverse branch condition!");
@@ -1116,6 +1120,10 @@ bool IfConverter::IfConvertTriangle(BBIn
return false;
}
+ if (CvtBBI->BB->hasAddressTaken())
+ // Conservatively abort if-conversion if BB's address is taken.
+ return false;
+
if (Kind == ICTriangleFalse || Kind == ICTriangleFRev)
if (TII->ReverseBranchCondition(Cond))
llvm_unreachable("Unable to reverse branch condition!");
@@ -1184,7 +1192,8 @@ bool IfConverter::IfConvertTriangle(BBIn
// block. By not merging them, we make it possible to iteratively
// ifcvt the blocks.
if (!HasEarlyExit &&
- NextBBI->BB->pred_size() == 1 && !NextBBI->HasFallThrough) {
+ NextBBI->BB->pred_size() == 1 && !NextBBI->HasFallThrough &&
+ !NextBBI->BB->hasAddressTaken()) {
MergeBlocks(BBI, *NextBBI);
FalseBBDead = true;
} else {
@@ -1234,6 +1243,10 @@ bool IfConverter::IfConvertDiamond(BBInf
return false;
}
+ if (TrueBBI.BB->hasAddressTaken() || FalseBBI.BB->hasAddressTaken())
+ // Conservatively abort if-conversion if either BB has its address taken.
+ return false;
+
// Put the predicated instructions from the 'true' block before the
// instructions from the 'false' block, unless the true block would clobber
// the predicate, in which case, do the opposite.
@@ -1382,7 +1395,8 @@ bool IfConverter::IfConvertDiamond(BBInf
// tail, add a unconditional branch to it.
if (TailBB) {
BBInfo &TailBBI = BBAnalysis[TailBB->getNumber()];
- bool CanMergeTail = !TailBBI.HasFallThrough;
+ bool CanMergeTail = !TailBBI.HasFallThrough &&
+ !TailBBI.BB->hasAddressTaken();
// There may still be a fall-through edge from BBI1 or BBI2 to TailBB;
// check if there are any other predecessors besides those.
unsigned NumPreds = TailBB->pred_size();
@@ -1551,6 +1565,9 @@ void IfConverter::CopyAndPredicateBlock(
/// i.e., when FromBBI's branch is being moved, add those successor edges to
/// ToBBI.
void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges) {
+ assert(!FromBBI.BB->hasAddressTaken() &&
+ "Removing a BB whose address is taken!");
+
ToBBI.BB->splice(ToBBI.BB->end(),
FromBBI.BB, FromBBI.BB->begin(), FromBBI.BB->end());
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