With the addition of CSSC (Common Short Sequence Compression)
instructions, a number of idioms match to single instructions (e.g.,
abs) that previously expanded to multi-instruction sequences.
This recognizes (some of) those idioms that are now misclassified and
returns a cost of a single instruction.
gcc/ChangeLog:
* config/aarch64/aarch64.cc (aarch64_rtx_costs): Support
idioms matching to CSSC instructions, if target CSSC is
present
Signed-off-by: Philipp Tomsich <philipp.toms...@vrull.eu>
---
gcc/config/aarch64/aarch64.cc | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 800a8b0e110..d89c94519e9 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -14431,10 +14431,17 @@ aarch64_rtx_costs (rtx x, machine_mode mode, int
outer ATTRIBUTE_UNUSED,
return false;
case CTZ:
- *cost = COSTS_N_INSNS (2);
+ if (!TARGET_CSSC)
+ {
+ /* Will be split to a bit-reversal + clz */
+ *cost = COSTS_N_INSNS (2);
+
+ if (speed)
+ *cost += extra_cost->alu.clz + extra_cost->alu.rev;
+ }
+ else
+ *cost = COSTS_N_INSNS (1);
- if (speed)
- *cost += extra_cost->alu.clz + extra_cost->alu.rev;
return false;
case COMPARE:
@@ -15373,12 +15380,17 @@ cost_plus:
}
else
{
- /* Integer ABS will either be split to
- two arithmetic instructions, or will be an ABS
- (scalar), which we don't model. */
- *cost = COSTS_N_INSNS (2);
- if (speed)
- *cost += 2 * extra_cost->alu.arith;
+ if (!TARGET_CSSC)
+ {
+ /* Integer ABS will either be split to
+ two arithmetic instructions, or will be an ABS
+ (scalar), which we don't model. */
+ *cost = COSTS_N_INSNS (2);
+ if (speed)
+ *cost += 2 * extra_cost->alu.arith;
+ }
+ else
+ *cost = COSTS_N_INSNS (1);
}
return false;
@@ -15388,13 +15400,15 @@ cost_plus:
{
if (VECTOR_MODE_P (mode))
*cost += extra_cost->vect.alu;
- else
+ else if (GET_MODE_CLASS (mode) == MODE_FLOAT)
{
/* FMAXNM/FMINNM/FMAX/FMIN.
TODO: This may not be accurate for all implementations, but
we do not model this in the cost tables. */
*cost += extra_cost->fp[mode == DFmode].addsub;
}
+ else if (TARGET_CSSC)
+ *cost = COSTS_N_INSNS (1);
}
return false;
--
2.34.1
