[llvm-commits] [llvm] r132201 - /llvm/trunk/lib/Transforms/Scalar/LICM.cpp

[Eli Friedman]

Author: efriedma
Date: Fri May 27 13:37:52 2011
New Revision: 132201

URL: http://llvm.org/viewvc/llvm-project?rev=132201&view=rev
Log:
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 .


Modified:
    llvm/trunk/lib/Transforms/Scalar/LICM.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LICM.cpp?rev=132201&r1=132200&r2=132201&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Fri May 27 13:37:52 2011
@@ -372,7 +372,11 @@
     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 @@
   // 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.