From: Vineet Gupta <vineetg@rivosinc.com>
To: gcc-patches@gcc.gnu.org
Cc: kito.cheng@gmail.com, Jeff Law <jeffreyalaw@gmail.com>,
Palmer Dabbelt <palmer@rivosinc.com>,
Philipp Tomsich <philipp.tomsich@vrull.eu>,
Christoph Mullner <christoph.muellner@vrull.eu>,
gnu-toolchain@rivosinc.co, Vineet Gupta <vineetg@rivosinc.com>
Subject: [PATCH] expansion: make layout of x_shift*cost[][][] more efficient
Date: Tue, 18 Apr 2023 11:17:45 -0700 [thread overview]
Message-ID: <20230418181745.987867-1-vineetg@rivosinc.com> (raw)
when debugging expmed.[ch] for PR/108987 saw that some of the cost arrays have
less than ideal layout as follows:
x_shift*cost[0..63][speed][modes]
We would want speed to be first index since a typical compile will have
that fixed, followed by mode and then the shift values.
It should be non-functional from compiler semantics pov, except
executing slightly faster due to better locality of shift values for
given speed and mode. And also a bit more intutive when debugging.
gcc/Changelog:
* expmed.h (x_shift*_cost): convert to int [speed][mode][shift].
(shift*_cost_ptr ()): Access x_shift*_cost array directly.
Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
---
gcc/expmed.h | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/gcc/expmed.h b/gcc/expmed.h
index c747a0da1637..d032beaef550 100644
--- a/gcc/expmed.h
+++ b/gcc/expmed.h
@@ -161,15 +161,14 @@ struct target_expmed {
struct expmed_op_cheap x_sdiv_pow2_cheap;
struct expmed_op_cheap x_smod_pow2_cheap;
- /* Cost of various pieces of RTL. Note that some of these are indexed by
- shift count and some by mode. */
+ /* Cost of various pieces of RTL. */
int x_zero_cost[2];
struct expmed_op_costs x_add_cost;
struct expmed_op_costs x_neg_cost;
- struct expmed_op_costs x_shift_cost[MAX_BITS_PER_WORD];
- struct expmed_op_costs x_shiftadd_cost[MAX_BITS_PER_WORD];
- struct expmed_op_costs x_shiftsub0_cost[MAX_BITS_PER_WORD];
- struct expmed_op_costs x_shiftsub1_cost[MAX_BITS_PER_WORD];
+ int x_shift_cost[2][NUM_MODE_IPV_INT][MAX_BITS_PER_WORD];
+ int x_shiftadd_cost[2][NUM_MODE_IPV_INT][MAX_BITS_PER_WORD];
+ int x_shiftsub0_cost[2][NUM_MODE_IPV_INT][MAX_BITS_PER_WORD];
+ int x_shiftsub1_cost[2][NUM_MODE_IPV_INT][MAX_BITS_PER_WORD];
struct expmed_op_costs x_mul_cost;
struct expmed_op_costs x_sdiv_cost;
struct expmed_op_costs x_udiv_cost;
@@ -395,8 +394,8 @@ neg_cost (bool speed, machine_mode mode)
inline int *
shift_cost_ptr (bool speed, machine_mode mode, int bits)
{
- return expmed_op_cost_ptr (&this_target_expmed->x_shift_cost[bits],
- speed, mode);
+ int midx = expmed_mode_index (mode);
+ return &this_target_expmed->x_shift_cost[speed][midex][bits];
}
/* Set the COST of doing a shift in MODE by BITS when optimizing for SPEED. */
@@ -421,8 +420,8 @@ shift_cost (bool speed, machine_mode mode, int bits)
inline int *
shiftadd_cost_ptr (bool speed, machine_mode mode, int bits)
{
- return expmed_op_cost_ptr (&this_target_expmed->x_shiftadd_cost[bits],
- speed, mode);
+ int midx = expmed_mode_index (mode);
+ return &this_target_expmed->x_shiftadd_cost[speed][midex][bits];
}
/* Set the COST of doing a shift in MODE by BITS followed by an add when
@@ -448,8 +447,8 @@ shiftadd_cost (bool speed, machine_mode mode, int bits)
inline int *
shiftsub0_cost_ptr (bool speed, machine_mode mode, int bits)
{
- return expmed_op_cost_ptr (&this_target_expmed->x_shiftsub0_cost[bits],
- speed, mode);
+ int midx = expmed_mode_index (mode);
+ return &this_target_expmed->x_shiftsub0_cost[speed][midex][bits];
}
/* Set the COST of doing a shift in MODE by BITS and then subtracting a
@@ -475,8 +474,8 @@ shiftsub0_cost (bool speed, machine_mode mode, int bits)
inline int *
shiftsub1_cost_ptr (bool speed, machine_mode mode, int bits)
{
- return expmed_op_cost_ptr (&this_target_expmed->x_shiftsub1_cost[bits],
- speed, mode);
+ int midx = expmed_mode_index (mode);
+ return &this_target_expmed->x_shiftsub1_cost[speed][midex][bits];
}
/* Set the COST of subtracting a shift in MODE by BITS from a value when
--
2.34.1
next reply other threads:[~2023-04-18 18:17 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-18 18:17 Vineet Gupta [this message]
2023-04-18 20:48 ` [PATCH v2] " Vineet Gupta
2023-04-19 7:05 ` Richard Biener
2023-04-21 16:15 ` [committed] " Vineet Gupta
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