https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116028
--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Surya Kumari Jangala <jskum...@gcc.gnu.org>: https://gcc.gnu.org/g:3c67a0fa1dd39a3378deb854a7fef0ff7fe38004 commit r15-2810-g3c67a0fa1dd39a3378deb854a7fef0ff7fe38004 Author: Surya Kumari Jangala <jskum...@linux.ibm.com> Date: Thu Dec 7 22:42:43 2023 -0600 lra: emit caller-save register spills before call insn [PR116028] LRA emits insns to save caller-save registers in the inheritance/splitting pass. In this pass, LRA builds EBBs (Extended Basic Block) and traverses the insns in the EBBs in reverse order from the last insn to the first insn. When LRA sees a write to a pseudo (that has been assigned a caller-save register), and there is a read following the write, with an intervening call insn between the write and read, then LRA generates a spill immediately after the write and a restore immediately before the read. The spill is needed because the call insn will clobber the caller-save register. If there is a write insn and a call insn in two separate BBs but belonging to the same EBB, the spill insn gets generated in the BB containing the write insn. If the write insn is in the entry BB, then the spill insn that is generated in the entry BB prevents shrink wrap from happening. This is because the spill insn references the stack pointer and hence the prolog gets generated in the entry BB itself. This patch ensures the the spill insn is generated before the call insn instead of after the write. This also ensures that the spill occurs only in the path containing the call. 2024-08-01 Surya Kumari Jangala <jskum...@linux.ibm.com> gcc: PR rtl-optimization/116028 * lra-constraints.cc (split_reg): Spill register before call insn. (latest_call_insn): New variable. (inherit_in_ebb): Track the latest call insn. gcc/testsuite: PR rtl-optimization/116028 * gcc.dg/ira-shrinkwrap-prep-1.c: Remove xfail for powerpc. * gcc.dg/pr10474.c: Remove xfail for powerpc.
