Modifies MipsAsmPrinter::isBlockOnlyReachableByFallthrough so that it handles delay slots correctly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128724 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsAsmPrinter.cpp b/lib/Target/Mips/MipsAsmPrinter.cpp
index 24f2e89..8dd6a37 100644
--- a/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -247,7 +247,32 @@
if (isa<SwitchInst>(bb->getTerminator()))
return false;
- return AsmPrinter::isBlockOnlyReachableByFallthrough(MBB);
+ // If this is a landing pad, it isn't a fall through. If it has no preds,
+ // then nothing falls through to it.
+ if (MBB->isLandingPad() || MBB->pred_empty())
+ return false;
+
+ // If there isn't exactly one predecessor, it can't be a fall through.
+ MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
+ ++PI2;
+
+ if (PI2 != MBB->pred_end())
+ return false;
+
+ // The predecessor has to be immediately before this block.
+ if (!Pred->isLayoutSuccessor(MBB))
+ return false;
+
+ // If the block is completely empty, then it definitely does fall through.
+ if (Pred->empty())
+ return true;
+
+ // Otherwise, check the last instruction.
+ // Check if the last terminator is an unconditional branch.
+ MachineBasicBlock::const_iterator I = Pred->end();
+ while (I != Pred->begin() && !(--I)->getDesc().isTerminator());
+
+ return !I->getDesc().isBarrier();
}
// Print out an operand for an inline asm expression.