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authorChandler Carruth <chandlerc@gmail.com>2012-03-24 23:03:27 +0000
committerChandler Carruth <chandlerc@gmail.com>2012-03-24 23:03:27 +0000
commit858cd1c33c6ba47cf3401b1e00862aa22302af10 (patch)
tree75e30f7b0a05c283f67a2ccccfdad5830334d97a
parent42c487d2e529489648176ebb8e9ef022c07ef785 (diff)
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Don't form a WeakVH around the sentinel node in the instructions BB
list. This is a bad idea. ;] I'm hopeful this is the bug that's showing up with the MSVC bots, but we'll see. It is definitely unnecessary. InstSimplify won't do anything to a terminator instruction, we don't need to even include it in the iteration range. We can also skip the now dead terminator check, although I've made it an assert to help document that this is an important invariant. I'm still a bit queasy about this because there is an implicit assumption that the terminator instruction cannot be RAUW'ed by the simplification code. While that appears to be true at the moment, I see no guarantee that would ensure it remains true in the future. I'm looking at the cleanest way to solve that... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153399 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--lib/Transforms/Utils/Local.cpp6
1 files changed, 2 insertions, 4 deletions
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index e65e567..96c6933 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -355,7 +355,8 @@ bool llvm::RecursivelyDeleteDeadPHINode(PHINode *PN) {
/// instructions in other blocks as well in this block.
bool llvm::SimplifyInstructionsInBlock(BasicBlock *BB, const TargetData *TD) {
bool MadeChange = false;
- for (BasicBlock::iterator BI = BB->begin(), E = BB->end(); BI != E; ) {
+ for (BasicBlock::iterator BI = BB->begin(), E = --BB->end(); BI != E; ) {
+ assert(!BI->isTerminator());
Instruction *Inst = BI++;
WeakVH BIHandle(BI);
@@ -366,9 +367,6 @@ bool llvm::SimplifyInstructionsInBlock(BasicBlock *BB, const TargetData *TD) {
continue;
}
- if (Inst->isTerminator())
- break;
-
MadeChange |= RecursivelyDeleteTriviallyDeadInstructions(Inst);
if (BIHandle != BI)
BI = BB->begin();