diff mbox series

[COMMITTED] RISC-V: fix thinko in riscv_register_move_cost ()

Message ID 20250113180645.2027158-1-vineetg@rivosinc.com
State Committed
Commit 7102620067eebfbfb895dccd5ddd26870178c83f
Headers
Series [COMMITTED] RISC-V: fix thinko in riscv_register_move_cost () |

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Commit Message

Vineet Gupta Jan. 13, 2025, 6:06 p.m. UTC 
  This seeming benign mistake caused a massive SPEC2017 Cactu regression
(2.1 trillion insn to 2.5 trillion) wiping out all the gains from my
recent sched1 improvement. Thankfully the issue was trivial to fix even
if hard to isolate.

On BPI3:

Before bug
----------
|  Performance counter stats for './cactusBSSN_r_base-1':
|
|       4,557,471.02 msec task-clock:u                     #    1.000 CPUs utilized
|              1,245      context-switches:u               #    0.273 /sec
|                  1      cpu-migrations:u                 #    0.000 /sec
|            205,376      page-faults:u                    #   45.064 /sec
|  7,291,944,801,307      cycles:u                         #    1.600 GHz
|  2,134,835,735,951      instructions:u                   #    0.29  insn per cycle
|     10,799,296,738      branches:u                       #    2.370 M/sec
|         15,308,966      branch-misses:u                  #    0.14% of all branches
|
|     4557.710508078 seconds time elapsed

Bug
---
|  Performance counter stats for './cactusBSSN_r_base-2':
|
|       4,801,813.79 msec task-clock:u                     #    1.000 CPUs utilized
|              8,066      context-switches:u               #    1.680 /sec
|                  1      cpu-migrations:u                 #    0.000 /sec
|            203,836      page-faults:u                    #   42.450 /sec
|  7,682,826,638,790      cycles:u                         #    1.600 GHz
|  2,503,133,291,344      instructions:u                   #    0.33  insn per cycle
   ^^^^^^^^^^^^^^^^^
|     10,799,287,796      branches:u                       #    2.249 M/sec
|         16,641,200      branch-misses:u                  #    0.15% of all branches
|
|     4802.616638386 seconds time elapsed
|

Fix
---
|  Performance counter stats for './cactusBSSN_r_base-3':
|
|       4,556,170.75 msec task-clock:u                     #    1.000 CPUs utilized
|              1,739      context-switches:u               #    0.382 /sec
|                  0      cpu-migrations:u                 #    0.000 /sec
|            203,458      page-faults:u                    #   44.655 /sec
|  7,289,854,613,923      cycles:u                         #    1.600 GHz
|  2,134,854,070,916      instructions:u                   #    0.29  insn per cycle
|     10,799,296,807      branches:u                       #    2.370 M/sec
|         15,403,357      branch-misses:u                  #    0.14% of all branches
|
|     4556.445490123 seconds time elapsed

Fixes: 46888571d242 ("RISC-V: Add cr and cf constraint")
Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>

gcc/ChangeLog:
	* config/riscv/riscv.cc (riscv_register_move_cost): Remove buggy
	check.

Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
---
 gcc/config/riscv/riscv.cc | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 3b5712429e46..a03b35bb9cfd 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -9591,8 +9591,7 @@  riscv_register_move_cost (machine_mode mode,
   bool from_is_gpr = from == GR_REGS || from == RVC_GR_REGS;
   bool to_is_fpr = to == FP_REGS || to == RVC_FP_REGS;
   bool to_is_gpr = to == GR_REGS || to == RVC_GR_REGS;
-  if ((from_is_fpr && to == to_is_gpr) ||
-      (from_is_gpr && to_is_fpr))
+  if ((from_is_fpr && to_is_gpr) || (from_is_gpr && to_is_fpr))
     return tune_param->fmv_cost;
 
   if (from == V_REGS)