[partial addressing of PR/109279]
RISCV splitters have restrictions to not create pesudos due to a combine
limitatation. And despite this being a split-during-combine limitation,
all split passes take the hit due to way define*_split are used in gcc.
With the original combine issue being fixed 61bee6aed2 ("combine: Don't
record for UNDO_MODE pointers into regno_reg_rtx array [PR104985]")
the RV splitters can now be relaxed.
This improves the codegen in general. e.g.
long long f(void) { return 0x0101010101010101ull; }
Before
li a0,0x01010000
addi a0,0x0101
slli a0,a0,16
addi a0,a0,0x0101
slli a0,a0,16
addi a0,a0,0x0101
ret
With patch
li a5,0x01010000
addi a5,a5,0x0101
mv a0,a5
slli a5,a5,32
add a0,a5,a0
ret
This is testsuite clean, no regression w/ patch.
========= Summary of gcc testsuite =========
| # of unexpected case / # of unique
unexpected case
| gcc | g++ | gfortran |
rv64imafdc/ lp64d/ medlow | 2 / 2 | 1 / 1 | 6 / 1 |
rv64imac/ lp64/ medlow | 3 / 3 | 1 / 1 | 43 /
8 |
rv32imafdc/ ilp32d/ medlow | 1 / 1 | 3 / 2 | 6 / 1 |
rv32imac/ ilp32/ medlow | 1 / 1 | 3 / 2 | 43 /
8 |
This came up as part of IRC chat on PR/109279 and was suggested by
Andrew Pinski.
Signed-off-by: Vineet Gupta <vine...@rivosinc.com>
---
gcc/config/riscv/riscv-protos.h | 4 +--
gcc/config/riscv/riscv.cc | 46 +++++++++++++--------------------
gcc/config/riscv/riscv.md | 8 +++---
3 files changed, 24 insertions(+), 34 deletions(-)
