[llvm-dev] deleting a range of instructions

Jajoo, Malhar via llvm-dev llvm-dev at lists.llvm.org
Mon Jun 12 08:59:57 PDT 2017


I am trying to delete a range of instructions ( specified as between [startIns , endIns) ) .
the endIns may not be in the same basic block as the start.

I keep getting the following error when trying to delete the last instruction in -

reference llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, true, false, void>, false, false>::operator*() const [OptionsT = llvm::ilist_detail::node_options<llvm::Instruction, true, false, void>, IsReverse = false, IsConst = false]: Assertion `!NodePtr->isKnownSentinel()' failed.

Following is my C++ code -

// delete all instructions between [start,end)
void deleteAllInstructionsInRange(Instruction* startInst,Instruction* endInst)
BasicBlock::iterator it(startInst);
BasicBlock::iterator it_end(endInst);
Instruction* currentInst ;
Instruction* lastInst ;

while(it != it_end)
currentInst = &*it;

if (!currentInst->use_empty())


Following is my IR -

define i32 @test2() {
  %calltmp = call i32 @UInt()
  %datasize = alloca i32
  switch i32 %calltmp, label %sw.bb.0 [
    i32 1, label %sw.bb.1
    i32 2, label %sw.bb.2
    i32 3, label %sw.bb.3
; %res = alloca i8 ------> deleted this
 ; store i8 0, i8* %res  ------> deleted this
  ;%datasize1 = load i32, i32* %datasize  ------> deleted this
  ;ret i32 %datasize1  ------> deleted this
  ret i32 undef ------> Unable to delete this

sw.bb.0:                                          ; preds = %entry
  %resclone0 = alloca i10
  store i10 0, i10* %resclone0
  %datasize1clone0 = load i32, i32* %datasize
  ret i32 %datasize1clone0

Any help will be appreciated.


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