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Revert "Make the memory GEP an inbounds GEP since the bounds check has happened somewhere else" #55674

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Revert "Make the memory GEP an inbounds GEP since the bounds check has happened somewhere else" #55674

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3 changes: 2 additions & 1 deletion src/cgutils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4280,8 +4280,9 @@ static jl_cgval_t emit_memoryref(jl_codectx_t &ctx, const jl_cgval_t &ref, jl_cg
ovflw = ctx.builder.CreateICmpUGE(ctx.builder.CreateAdd(offset, mlen), ctx.builder.CreateNUWAdd(mlen, mlen));
}
#endif
//Is this change fine
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It looks like we must be able to do this arithmetic later, and while we know this computation of bidx0 cannot overflow (because of checking ovflw), we don't appear to know that the intermediate step won't overflow:

            Value *bidx0 = ctx.builder.CreateSub(
                ctx.builder.CreatePtrToInt(newdata, ctx.types().T_size),
                ctx.builder.CreatePtrToInt(mptr, ctx.types().T_size));

boffset = ctx.builder.CreateMul(offset, elsz);
newdata = ctx.builder.CreateInBoundsGEP(getInt8Ty(ctx.builder.getContext()), data, boffset);
newdata = ctx.builder.CreateGEP(getInt8Ty(ctx.builder.getContext()), data, boffset);
(void)boffset; // LLVM is very bad at handling GEP with types different from the load
if (bc) {
BasicBlock *failBB, *endBB;
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