Patch is originally from Siarhei Volkau <lis8...@gmail.com>.
RISC-V has a zero register (x0) which we can use to store zero into memory
without loading the constant into a distinct register. Adjust the
constraints
of the 32-bit movdi_32bit pattern to recognize that we can store 0.0 into
memory using x0 as the source register.
This patch only affects RISC-V. It has been regression tested on
riscv64-elf.
Jeff has also tested this in his tester (riscv64-elf and riscv32-elf) with
no
regressions.
PR target/70557
gcc/
* config/riscv/riscv.md (movdi_32bit): Add "J" constraint to allow
storing 0
directly to memory.
