[RISC-V][PR target/121213] Avoid unnecessary sign extension in amoswap sequenceHEADtrunkmaster

This is Austin's work to remove the redundant sign extension seen in pr121213.

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The .w form of amoswap will sign extend its result from 32 to 64 bits, thus any
explicit sign extension insn doing the same is redundant.

This uses Jivan's approach of allocating a DI temporary for an extended result
and using a promoted subreg extraction to get that result into the final
destination.

Tested with no regressions on riscv32-elf and riscv64-elf and bootstrapped on
the BPI and pioneer systems.

	PR target/121213
gcc/
	* config/riscv/sync.md (amo_atomic_exchange_extended<mode>):
	Separate insn with sign extension for 64 bit targets.

gcc/testsuite
	* gcc.target/riscv/amo/pr121213.c: Remove xfail.

0 files changed, 0 insertions, 0 deletions