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expansion: make layout of x_shift*cost[][][] more efficient

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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>
This commit is contained in:
Vineet Gupta 2023-02-28 19:27:26 -08:00
parent e6f689d090
commit 1fe9bef9f5
1 changed files with 13 additions and 14 deletions
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27
gcc/expmed.h
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@ -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][midx][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][midx][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][midx][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][midx][bits];
}
/* Set the COST of subtracting a shift in MODE by BITS from a value when