Bulk erasing instructions without RAUWing them is unsafe. Instead, break them

into a new BB that has no predecessors.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77433 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2009-07-29 05:17:50 +00:00
parent e53a600f06
commit 0efa921736
2 changed files with 188 additions and 7 deletions

View File

@ -519,17 +519,19 @@ struct VISIBILITY_HIDDEN ExitOpt : public LibCallOptimization {
TerminatorInst *OldTI = CI->getParent()->getTerminator();
// Create the return after the call.
ReturnInst *RI = B.CreateRet(CI->getOperand(1));
// Drop all successor phi node entries.
for (unsigned i = 0, e = OldTI->getNumSuccessors(); i != e; ++i)
OldTI->getSuccessor(i)->removePredecessor(CI->getParent());
// Erase all instructions from after our return instruction until the end of
// the block.
BasicBlock::iterator FirstDead = RI; ++FirstDead;
CI->getParent()->getInstList().erase(FirstDead, CI->getParent()->end());
// Split the basic block after the call to exit.
BasicBlock::iterator FirstDead = CI; ++FirstDead;
CI->getParent()->splitBasicBlock(FirstDead);
B.SetInsertPoint(B.GetInsertBlock());
// Remove the branch that splitBB created and insert a return instead.
CI->getParent()->getTerminator()->eraseFromParent();
B.CreateRet(CI->getOperand(1));
return CI;
}
};

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@ -0,0 +1,179 @@
; RUN: llvm-as < %s | opt -simplify-libcalls
; PR4641
%struct.__sFILE = type { i8*, i32, i32, i16, i16, %struct.__sbuf, i32, i8*, i32 (i8*)*, i32 (i8*, i8*, i32)*, i64 (i8*, i64, i32)*, i32 (i8*, i8*, i32)*, %struct.__sbuf, i8*, i32, [3 x i8], [1 x i8], %struct.__sbuf, i32, i64, %struct.pthread_mutex*, %struct.pthread*, i32, i32, %union.anon }
%struct.__sbuf = type { i8*, i32, [4 x i8] }
%struct.pthread = type opaque
%struct.pthread_mutex = type opaque
%union.anon = type { i64, [120 x i8] }
@.str13 = external constant [2 x i8] ; <[2 x i8]*> [#uses=1]
@.str14 = external constant [2 x i8] ; <[2 x i8]*> [#uses=1]
define i32 @main(i32 %argc, i8** %argv) nounwind {
entry:
br i1 undef, label %if.then.i, label %xmalloc.exit
if.then.i: ; preds = %entry
unreachable
xmalloc.exit: ; preds = %entry
br i1 undef, label %if.then.i11, label %xmalloc.exit13
if.then.i11: ; preds = %xmalloc.exit
unreachable
xmalloc.exit13: ; preds = %xmalloc.exit
br label %while.cond
while.cond: ; preds = %sw.bb124, %if.end59, %if.end, %while.cond, %xmalloc.exit13
switch i32 undef, label %sw.default [
i32 -1, label %for.cond
i32 0, label %while.cond
i32 4097, label %sw.bb36
i32 102, label %sw.bb55
i32 111, label %sw.bb55
i32 108, label %sw.bb62
i32 99, label %sw.bb84
i32 86, label %sw.bb114
i32 66, label %sw.bb124
]
sw.bb36: ; preds = %while.cond
br i1 undef, label %if.end, label %if.then
if.then: ; preds = %sw.bb36
unreachable
if.end: ; preds = %sw.bb36
br label %while.cond
sw.bb55: ; preds = %while.cond, %while.cond
br i1 undef, label %if.end59, label %if.then58
if.then58: ; preds = %sw.bb55
br label %if.end59
if.end59: ; preds = %if.then58, %sw.bb55
br label %while.cond
sw.bb62: ; preds = %while.cond
unreachable
sw.bb84: ; preds = %while.cond
unreachable
sw.bb114: ; preds = %while.cond
unreachable
sw.bb124: ; preds = %while.cond
br label %while.cond
sw.default: ; preds = %while.cond
unreachable
for.cond: ; preds = %while.cond
br i1 undef, label %if.end167, label %if.then8.i
if.then8.i: ; preds = %for.cond
unreachable
if.end167: ; preds = %for.cond
br i1 undef, label %if.then174, label %if.end175
if.then174: ; preds = %if.end167
unreachable
if.end175: ; preds = %if.end167
br i1 undef, label %if.then179, label %if.end181
if.then179: ; preds = %if.end175
unreachable
if.end181: ; preds = %if.end175
br i1 undef, label %if.then.i.i189, label %while.cond.i194
if.then.i.i189: ; preds = %if.end181
unreachable
while.cond.i194: ; preds = %if.end181
br i1 undef, label %while.body.i198, label %for.cond.i.i202
while.body.i198: ; preds = %while.cond.i194
unreachable
for.cond.i.i202: ; preds = %while.cond.i194
br i1 undef, label %if.end197, label %if.then191
if.then191: ; preds = %for.cond.i.i202
unreachable
if.end197: ; preds = %for.cond.i.i202
br label %for.cond.i144
for.cond.i144: ; preds = %for.body.i145, %if.end197
br i1 undef, label %for.body.i145, label %for.cond24.i
for.body.i145: ; preds = %for.cond.i144
br label %for.cond.i144
for.cond24.i: ; preds = %for.cond.i144
br label %for.cond78.i
for.cond78.i: ; preds = %for.body84.i, %for.cond24.i
br i1 undef, label %for.end94.i, label %for.body84.i
for.body84.i: ; preds = %for.cond78.i
br label %for.cond78.i
for.end94.i: ; preds = %for.cond78.i
br i1 undef, label %if.then.i.i139, label %linebuffer_init.exit142
if.then.i.i139: ; preds = %for.end94.i
br label %linebuffer_init.exit142
linebuffer_init.exit142: ; preds = %if.then.i.i139, %for.end94.i
br i1 undef, label %if.then.i.i124, label %linebuffer_init.exit129
if.then.i.i124: ; preds = %linebuffer_init.exit142
unreachable
linebuffer_init.exit129: ; preds = %linebuffer_init.exit142
br i1 undef, label %if.then.i.i110, label %linebuffer_init.exit113
if.then.i.i110: ; preds = %linebuffer_init.exit129
unreachable
linebuffer_init.exit113: ; preds = %linebuffer_init.exit129
br i1 undef, label %if.then.i.i98, label %linebuffer_init.exit
if.then.i.i98: ; preds = %linebuffer_init.exit113
br label %linebuffer_init.exit
linebuffer_init.exit: ; preds = %if.then.i.i98, %linebuffer_init.exit113
br i1 undef, label %if.then227, label %while.cond.i50
if.then227: ; preds = %linebuffer_init.exit
unreachable
while.cond.i50: ; preds = %linebuffer_init.exit
br i1 undef, label %while.end339, label %while.body334
while.body334: ; preds = %while.cond.i50
unreachable
while.end339: ; preds = %while.cond.i50
br i1 undef, label %if.then344, label %if.end346
if.then344: ; preds = %while.end339
unreachable
if.end346: ; preds = %while.end339
call void @exit(i32 0) nounwind
%cond392 = select i1 undef, i8* getelementptr ([2 x i8]* @.str13, i32 0, i32 0), i8* getelementptr ([2 x i8]* @.str14, i32 0, i32 0) ; <i8*> [#uses=1]
%call393 = call %struct.__sFILE* @fopen(i8* undef, i8* %cond392) nounwind ; <%struct.__sFILE*> [#uses=0]
unreachable
}
declare %struct.__sFILE* @fopen(i8*, i8*)
declare void @exit(i32)