<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Feb 1, 2019, at 2:25 PM, Eli Friedman via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">I was thinking of a model something like this: 32-bit pointers are addrspace 0, 64-bit pointers are addrspace 1. ISD::LOAD/STORE in addrspace 0 are not legal: they're custom-lowered to operations in addrspace 1. (An addrspacecast from 0 to 1 is just zero-extension.) At that point, since the cast from 32 bits to 64 bits is explicitly represented, we can optimize it in the DAG or IR. For example, we can transform a load of an inbounds gep in addrspace 0 into to a load of an inbounds gep in addrspace 1.</span></div></blockquote><br class=""></div><div>+1</div><div><br class=""></div><div>This is basically what we do for one address space on AMDGPU</div><div><br class=""></div><div>-Matt</div><br class=""></body></html>