RPCSX/llvm
1
0
Fork 0
mirror of https://github.com/RPCSX/llvm.git synced 2024-11-29 22:50:47 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Guard MemoryBuiltins against self-looping GEPs, which can occur in unreachable code due to constant propagation.

Browse Source 
Fixes PR13621.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162098 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer 2012-08-17 14:16:37 +00:00
parent 4e81d40545
commit 823573a381
2 changed files with 21 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
lib/Analysis/MemoryBuiltins.cpp
View File

@ -473,6 +473,10 @@ ObjectSizeOffsetVisitor::visitExtractValueInst(ExtractValueInst&) {
}
SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
// Ignore self-referencing GEPs, they can occur in unreachable code.
if (&GEP == GEP.getPointerOperand())
return unknown();
SizeOffsetType PtrData = compute(GEP.getPointerOperand());
if (!bothKnown(PtrData) || !GEP.hasAllConstantIndices())
return unknown();

17
test/Transforms/InstCombine/objsize.ll
View File

@ -238,3 +238,20 @@ xpto:
return:
ret i32 42
}
; CHECK: @PR13621
define i32 @PR13621(i1 %bool) nounwind {
entry:
%cond = or i1 %bool, true
br i1 %cond, label %return, label %xpto
; technically reachable, but this malformed IR may appear as a result of constant propagation
xpto:
%gep = getelementptr i8* %gep, i32 1
%o = call i32 @llvm.objectsize.i32(i8* %gep, i1 true)
; CHECK: ret i32 undef
ret i32 %o
return:
ret i32 7
}