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fix PR8102, a case where we'd copyValue from a value that we already 

deleted.  Fix this by doing the copyValue's before we delete stuff!

The testcase only repros the problem on my system with valgrind.

llvm-svn: 113820
This commit is contained in:
Chris Lattner 2010-09-14 00:19:00 +00:00
parent 93c9b2ea93
commit f1144f0929
2 changed files with 31 additions and 11 deletions
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22
llvm/lib/Transforms/Scalar/LICM.cpp
View File

@ -837,6 +837,17 @@ void LICM::PromoteAliasSet(AliasSet &AS) {
ReplacedLoads[ALoad] = NewVal;
}
// If the preheader load is itself a pointer, we need to tell alias analysis
// about the new pointer we created in the preheader block and about any PHI
// nodes that just got inserted.
if (PreheaderLoad->getType()->isPointerTy()) {
// Copy any value stored to or loaded from a must-alias of the pointer.
CurAST->copyValue(SomeValue, PreheaderLoad);
for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i)
CurAST->copyValue(SomeValue, NewPHIs[i]);
}
// Now that everything is rewritten, delete the old instructions from the body
// of the loop. They should all be dead now.
for (unsigned i = 0, e = LoopUses.size(); i != e; ++i) {
@ -867,17 +878,6 @@ void LICM::PromoteAliasSet(AliasSet &AS) {
User->eraseFromParent();
}
// If the preheader load is itself a pointer, we need to tell alias analysis
// about the new pointer we created in the preheader block and about any PHI
// nodes that just got inserted.
if (PreheaderLoad->getType()->isPointerTy()) {
// Copy any value stored to or loaded from a must-alias of the pointer.
CurAST->copyValue(SomeValue, PreheaderLoad);
for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i)
CurAST->copyValue(SomeValue, NewPHIs[i]);
}
// fwew, we're done!
}

20
llvm/test/Transforms/LICM/crash.ll
View File

@ -39,3 +39,23 @@ for.body: ; preds = %for.body, %entry
store i32 undef, i32* @g_8, align 4
br label %for.body
}
; PR8102
define void @test3() {
entry:
%__first = alloca { i32* }
br i1 undef, label %for.cond, label %for.end
for.cond: ; preds = %for.cond, %entry
%tmp1 = getelementptr { i32*}* %__first, i32 0, i32 0
%tmp2 = load i32** %tmp1, align 4
%call = tail call i32* @test3helper(i32* %tmp2)
%tmp3 = getelementptr { i32*}* %__first, i32 0, i32 0
store i32* %call, i32** %tmp3, align 4
br i1 false, label %for.cond, label %for.end
for.end: ; preds = %for.cond, %entry
ret void
}
declare i32* @test3helper(i32*)