search for: pre_dec

...use_end(); I != E; ++I) { SDNode *Use = *I; 1. Make the loop skip cases where Use->getOpcode() == ISD::ADD and then Use->getOpcode() == ISD::SUB and try to figure out whether the problem is related to folding with ADDs or SUBs. 2. In the problematic case, skip the loop when AM == ISD::PRE_DEC, and see if the problem is related to pre-increment or pre-decrement. Looking briefly at the code in comment 5 of PR15581, is that the pre-decrement case? I can't test that case on PPC, so I can certainly believe that there is a problem somewhere. The relevant code is a little farther down:...

Hello Hal, I have a strong suspicion that your constant folding optimization introduced at r174746 is broken on ARM. There is a bug about it: http://llvm.org/bugs/show_bug.cgi?id=15581 There is no such issue with 3.2, and reverting r174746 on top of r178740 also fixes the problem. I'm trying to fix it myself, but still have no good ideas; so it would be great to have an advice from you.

...that the pre-decrement case? > I can't test that case on PPC, so I can certainly believe that there is a problem somewhere. > The relevant code is a little farther down: > > APInt OV = > cast<ConstantSDNode>(Offset)->getAPIntValue(); > if (AM == ISD::PRE_DEC) > OV = -OV; > > ConstantSDNode *CN = > cast<ConstantSDNode>(OtherUses[i]->getOperand(OffsetIdx)); > APInt CNV = CN->getAPIntValue(); > if (OtherUses[i]->getOpcode() == ISD::SUB && OffsetIdx == 1) > CNV += OV; >...

On 04/10/2013 10:22 PM, Hal Finkel wrote: >> Okay, great! Can you please generate a test case? In case you don't >> know, an easy way is this: place an assert that will crash the code >> generation in the pre-dec case you've highlighted, then use bugpoint >> to produce a reduced test case for the crash. > > [list not cc'd] > > Were you able to make