[llvm-commits] [llvm] r141203 - in /llvm/trunk: lib/Transforms/InstCombine/InstructionCombining.cpp test/Transforms/InstCombine/2010-11-01-lshr-mask.ll

[Jim Grosbach]

Author: grosbach
Date: Wed Oct  5 15:05:00 2011
New Revision: 141203

URL: http://llvm.org/viewvc/llvm-project?rev=141203&view=rev
Log:
Update InstCombine worklist after instruction transform is complete.

When updating the worklist for InstCombine, the Add/AddUsersToWorklist
functions may access the instruction(s) being added, for debug output for
example. If the instructions aren't yet added to the basic block, this
can result in a crash. Finish the instruction transformation before
adjusting the worklist instead.

rdar://10238555

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
    llvm/trunk/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp?rev=141203&r1=141202&r2=141203&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp Wed Oct  5 15:05:00 2011
@@ -2009,21 +2009,18 @@
       ++NumCombined;
       // Should we replace the old instruction with a new one?
       if (Result != I) {
-        DEBUG(errs() << "IC: Old = " << *I << '\n'
-                     << "    New = " << *Result << '\n');
-
         if (!I->getDebugLoc().isUnknown())
           Result->setDebugLoc(I->getDebugLoc());
         // Everything uses the new instruction now.
         I->replaceAllUsesWith(Result);
 
-        // Push the new instruction and any users onto the worklist.
-        Worklist.Add(Result);
-        Worklist.AddUsersToWorkList(*Result);
-
-        // Move the name to the new instruction first.
+        // Move the name to the new instruction.
         Result->takeName(I);
 
+        DEBUG(errs() << "IC: Old = " << *I << '\n'
+                     << "    New = " << *Result << '\n');
+
+
         // Insert the new instruction into the basic block...
         BasicBlock *InstParent = I->getParent();
         BasicBlock::iterator InsertPos = I;
@@ -2035,6 +2032,10 @@
         InstParent->getInstList().insert(InsertPos, Result);
 
         EraseInstFromFunction(*I);
+
+        // Push the new instruction and any users onto the worklist.
+        Worklist.Add(Result);
+        Worklist.AddUsersToWorkList(*Result);
       } else {
 #ifndef NDEBUG
         DEBUG(errs() << "IC: Mod = " << OrigI << '\n'

Modified: llvm/trunk/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll?rev=141203&r1=141202&r2=141203&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll Wed Oct  5 15:05:00 2011
@@ -5,8 +5,8 @@
 define i32 @main(i32 %argc) nounwind ssp {
 entry:
   %tmp3151 = trunc i32 %argc to i8
-; CHECK: %tmp3162 = shl i8 %tmp3151, 5
-; CHECK: and i8 %tmp3162, 64
+; CHECK: %0 = shl i8 %tmp3151, 5
+; CHECK: and i8 %0, 64
 ; CHECK-NOT: shl
 ; CHECK-NOT: shr
   %tmp3161 = or i8 %tmp3151, -17