Hi, all, The nds32 target has two kinds of instructions for returning to the caller. One is normal 'ret' instruction which takes $lp as return address; and the other is 'pop25' instruction which perform registers pop and use $lp as return address in a single step.
However, the current design of 'pop25' on trunk is incomplete. We lost "return" rtx semantic in the pattern so that gcc will get wrong data flow across pop25 if we configure it with --enable-checking=yes. To fix this issue, we have dummy pattern 'pop25return' to tell gcc that there is a return behavior after pop25 instruction. This patch was committed last week before stage 4: https://gcc.gnu.org/r219710 gcc/ChangeLog 2015-01-16 Chung-Ju Wu <jasonw...@gmail.com> * config/nds32/constants.md (UNSPEC_VOLATILE_POP25_RETURN): New. * config/nds32/nds32.md (pop25return): New. * config/nds32/nds32.c (nds32_expand_epilogue_v3pop): Emit pop25return pattern. Best regards, jasonwucj
0007-Add-dummy-pattern-pop25return-to-tell-gcc-there-is-a.patch
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