On 9/5/24 1:50 PM, Raphael Moreira Zinsly wrote:
Changes since v1:
- Fix bit31.
- Remove negative shift checks.
- Fix synthesis-7.c expected output.
-- >8 --
Improve handling of large constants in riscv_build_integer, generate
better code for constants where the high half can be constructed
by shifting/shiftNadding the low half or if the halves differ by less
than 2k.
gcc/ChangeLog:
* config/riscv/riscv.cc (riscv_build_integer): Detect new case
of constants that can be improved.
(riscv_move_integer): Add synthesys for concatening constants
without Zbkb.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/synthesis-7.c: Adjust expected output.
* gcc.target/riscv/synthesis-12.c: New test.
* gcc.target/riscv/synthesis-13.c: New test.
* gcc.target/riscv/synthesis-14.c: New test.
---
gcc/config/riscv/riscv.cc | 138 +++++++++++++++++-
gcc/testsuite/gcc.target/riscv/synthesis-12.c | 26 ++++
gcc/testsuite/gcc.target/riscv/synthesis-13.c | 26 ++++
gcc/testsuite/gcc.target/riscv/synthesis-14.c | 28 ++++
gcc/testsuite/gcc.target/riscv/synthesis-7.c | 2 +-
5 files changed, 213 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/riscv/synthesis-12.c
create mode 100644 gcc/testsuite/gcc.target/riscv/synthesis-13.c
create mode 100644 gcc/testsuite/gcc.target/riscv/synthesis-14.c
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index a38cb72f09f..df8a5a1c1e2 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -1231,6 +1231,122 @@ riscv_build_integer (struct riscv_integer_op *codes,
HOST_WIDE_INT value,
}
}
+ else if (cost > 4 && TARGET_64BIT && can_create_pseudo_p ()
+ && allow_new_pseudos)
+ {
+ struct riscv_integer_op alt_codes[RISCV_MAX_INTEGER_OPS];
+ int alt_cost;
+
+ unsigned HOST_WIDE_INT loval = value & 0xffffffff;
+ unsigned HOST_WIDE_INT hival = (value & ~loval) >> 32;
+ bool bit31 = (loval & 0x80000000) != 0;
+ int trailing_shift = ctz_hwi (loval) - ctz_hwi (hival);
+ int leading_shift = clz_hwi (loval) - clz_hwi (hival);
+ int shiftval = 0;
+
+ /* Adjust the shift into the high half accordingly. */
+ if ((trailing_shift > 0 && hival == (loval >> trailing_shift)))
+ shiftval = 32 - trailing_shift;
+ else if ((leading_shift > 0 && hival == (loval << leading_shift)))
+ shiftval = 32 + leading_shift;
+
+ if (shiftval && !bit31)
+ alt_cost = 2 + riscv_build_integer_1 (alt_codes, sext_hwi (loval, 32),
+ mode);
+
+ /* For constants where the upper half is a shift of the lower half we
+ can do a shift followed by an or. */
+ if (shiftval && alt_cost < cost && !bit31)
So if shiftval is not zero and bit31 is also not zero, then doesn't this
test alt_cost < cost without having initialized alt_cost? I think this
can be fixed by testing !bit31 before the alt_cost < cost check.
+ {
+ /* We need to save the first constant we build. */
+ alt_codes[alt_cost - 3].save_temporary = true;
+
+ /* Now we want to shift the previously generated constant into the
+ high half. */
+ alt_codes[alt_cost - 2].code = ASHIFT;
+ alt_codes[alt_cost - 2].value = shiftval;
+ alt_codes[alt_cost - 2].use_uw = false;
+ alt_codes[alt_cost - 2].save_temporary = false;
+
+ /* And the final step, IOR the two halves together. Since this uses
+ the saved temporary, use CONCAT similar to what we do for Zbkb. */
+ alt_codes[alt_cost - 1].code = CONCAT;
+ alt_codes[alt_cost - 1].value = 0;
+ alt_codes[alt_cost - 1].use_uw = false;
+ alt_codes[alt_cost - 1].save_temporary = false;
+
+ memcpy (codes, alt_codes, sizeof (alt_codes));
+ cost = alt_cost;
+ }
+
+ if (cost > 4 && !bit31 && TARGET_ZBA)
+ {
+ int value = 0;
+
+ /* Check for a shNadd. */
+ if (hival == loval * 3)
+ value = 3;
+ else if (hival == loval * 5)
+ value = 5;
+ else if (hival == loval * 9)
+ value = 9;
+
+ if (value)
+ alt_cost = 2 + riscv_build_integer_1 (alt_codes,
+ sext_hwi (loval, 32), mode);
+
+ /* For constants where the upper half is a shNadd of the lower half
+ we can do a similar transformation. */
+ if (value && alt_cost < cost)
+ {
+ alt_codes[alt_cost - 3].save_temporary = true;
+ alt_codes[alt_cost - 2].code = FMA;
+ alt_codes[alt_cost - 2].value = value;
+ alt_codes[alt_cost - 2].use_uw = false;
+ alt_codes[alt_cost - 2].save_temporary = false;
+ alt_codes[alt_cost - 1].code = CONCAT;
+ alt_codes[alt_cost - 1].value = 0;
+ alt_codes[alt_cost - 1].use_uw = false;
+ alt_codes[alt_cost - 1].save_temporary = false;
+
+ memcpy (codes, alt_codes, sizeof (alt_codes));
+ cost = alt_cost;
+ }
+ }
+
+ if (cost > 4 && !bit31)
+ {
+ int value = hival - loval;
+
+ /* For constants were the halves differ by less than 2048 we can
+ generate the upper half by using an addi on the lower half then
+ using a shift 32 followed by an or. */
+ if (abs (value) <= 2047)
Using IN_RANGE (value, -2048, 2047) would probably be better and capture
one more case, -2048 :-)
I know your out of the office, so I'll make those two minor adjustments
do a quick test and push this to the trunk.
jeff
