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authorEdwin Török <edwintorok@gmail.com>2009-05-29 09:46:03 +0000
committerEdwin Török <edwintorok@gmail.com>2009-05-29 09:46:03 +0000
commit47cf884b75bc2b005017799f8834d1029353488b (patch)
tree906c0fbe03659bf1f13b64f87e834fff00ac67f9
parent1c057ee3b353a8c80d7bd9e2d4ea6526d88c7b05 (diff)
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Add a DEBUG() output to GVN that prints the instruction clobbering a load.
This is useful when trying to figure out why GVN didn't eliminate redundant loads. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72565 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--lib/Transforms/Scalar/GVN.cpp12
1 files changed, 11 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 222320f..946c33e 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -1158,8 +1158,18 @@ bool GVN::processLoad(LoadInst *L, SmallVectorImpl<Instruction*> &toErase) {
MemDepResult dep = MD->getDependency(L);
// If the value isn't available, don't do anything!
- if (dep.isClobber())
+ if (dep.isClobber()) {
+ DEBUG(
+ // fast print dep, using operator<< on instruction would be too slow
+ DOUT << "GVN: load ";
+ WriteAsOperand(*DOUT.stream(), L);
+ Instruction *I = dep.getInst();
+ DOUT << " is clobbered by " << I->getOpcodeName() << " instruction ";
+ WriteAsOperand(*DOUT.stream(), I, false);
+ DOUT << "\n";
+ );
return false;
+ }
// If it is defined in another block, try harder.
if (dep.isNonLocal())