We would like to split the SP adjustment to reduce the instructions in
prologue and epilogue as the following case. In this way, the offset of
the callee saved register could fit in a single store.
add sp,sp,-2032
sw ra,2028(sp)
sw s0,2024(sp)
sw s1,2020(sp)
sw s3,2012(sp)
sw s4,2008(sp)
add sp,sp,-64
Differential Revision: https://reviews.llvm.org/D68011
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@373688 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Currently the RISC-V backend does not realign the stack. This can be an issue even for the RV32I/RV64I ABIs (where the stack is 16-byte aligned), though is rare. It will be much more comment with RV32E (though the alignment requirements for common data types remain under-documented...).
This patch adds minimal support for stack realignment. It should cope with large realignments. It will error out if the stack needs realignment and variable sized objects are present.
It feels like a lot of the code like getFrameIndexReference and determineFrameLayout could be refactored somehow, as right now it feels fiddly and brittle. We also seem to allocate a lot more memory than GCC does for equivalent C code.
Reviewers: asb
Reviewed By: asb
Subscribers: wwei, jrtc27, s.egerton, MaskRay, Jim, lenary, hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62007
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@368300 91177308-0d34-0410-b5e6-96231b3b80d8
