FRM mode switching state machine has DYN as default state which it also
fallsback to after transitioning to other states such as DYN_CALL.
Currently TARGET_MODE_EMIT generates a FRM restore on any transition to
DYN leading to spurious/extraneous FRM restores.
Only do this if an interim static Rounding Mode was observed in the state
machine.
This reduces the number of FRM writes in SPEC2017 -Ofast -mrv64gcv build
significantly.
Before After
------------- -------------
frrm fsrmi fsrm frrm fsrmi frrm
perlbench_r 42 0 4 17 0 1
cpugcc_r 167 0 17 11 0 0
bwaves_r 16 0 1 16 0 1
mcf_r 11 0 0 11 0 0
cactusBSSN_r 76 0 27 19 0 1
namd_r 119 0 63 14 0 1
parest_r 168 0 114 24 0 1
povray_r 123 1 17 26 1 6
lbm_r 6 0 0 6 0 0
omnetpp_r 17 0 1 17 0 1
wrf_r 2287 13 1956 1268 13 1603
cpuxalan_r 17 0 1 17 0 1
ldecod_r 11 0 0 11 0 0
x264_r 14 0 1 11 0 0
blender_r 724 12 182 61 12 42
cam4_r 324 13 169 45 13 20
deepsjeng_r 11 0 0 11 0 0
imagick_r 265 16 34 132 16 25
leela_r 12 0 0 12 0 0
nab_r 13 0 1 13 0 1
exchange2_r 16 0 1 16 0 1
fotonik3d_r 20 0 11 19 0 1
roms_r 33 0 23 21 0 1
xz_r 6 0 0 6 0 0
--------------- --------------
4498 55 2623 1804 55 1707
gcc/ChangeLog:
* config/riscv/riscv.cc (riscv_emit_frm_mode_set): check
STATIC_FRM_P for trnsition to DYN.
Signed-off-by: Vineet Gupta <vine...@rivosinc.com>
---
gcc/config/riscv/riscv.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index f1b4b20499fc..37f3ace49a8b 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -12121,7 +12121,7 @@ riscv_emit_frm_mode_set (int mode, int prev_mode)
&& prev_mode != riscv_vector::FRM_DYN
&& prev_mode != riscv_vector::FRM_DYN_CALL)
/* Restore frm value when switch to DYN mode. */
- || (mode == riscv_vector::FRM_DYN
+ || (STATIC_FRM_P (cfun) && mode == riscv_vector::FRM_DYN
&& prev_mode != riscv_vector::FRM_DYN_CALL);
if (restore_p)
--
2.43.0
