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[RISCV] Fix PR 106586: riscv32 vs ZBS
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The problem here is two fold. With RISCV32, 32bit
const_int are always signed extended to 64bit in HWI.
So that means for SINGLE_BIT_MASK_OPERAND, it should
mask off the upper bits to see it is a single bit
for !TARGET_64BIT.
Plus there are a few locations which forget to call
trunc_int_for_mode when generating a SImode constant
so they are not sign extended correctly for HWI.
The predicates single_bit_mask_operand and
not_single_bit_mask_operand need get the same handling
as SINGLE_BIT_MASK_OPERAND so just use SINGLE_BIT_MASK_OPERAND.

OK? Built and tested on riscv32-linux-gnu and riscv64-linux-gnu with
--with-arch=rvNimafdc_zba_zbb_zbc_zbs where N is replaced with 32 or 64.

Thanks,
Andrew Pinski

gcc/ChangeLog:

	PR target/106586
	* config/riscv/predicates.md (single_bit_mask_operand):
	Use SINGLE_BIT_MASK_OPERAND instead of directly calling pow2p_hwi.
	(not_single_bit_mask_operand): Likewise.
	* config/riscv/riscv.cc (riscv_build_integer_1): Don't special case
	1<<31 for 32bits as it is already handled.
	Call trunc_int_for_mode on the upper part after the subtraction.
	(riscv_move_integer): Call trunc_int_for_mode before generating
	the integer just make sure the constant has been sign extended
	corectly.
	(riscv_emit_int_compare): Call trunc_int_for_mode after doing the
	addition for the new rhs.
	* config/riscv/riscv.h (SINGLE_BIT_MASK_OPERAND): If !TARGET64BIT,
	then mask off the upper 32bits of the HWI as it will be sign extended.
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apinski-cavium committed Aug 24, 2022
1 parent 95989ab commit 2c721ea
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Showing 3 changed files with 14 additions and 6 deletions.
4 changes: 2 additions & 2 deletions gcc/config/riscv/predicates.md
Original file line number Diff line number Diff line change
Expand Up @@ -226,11 +226,11 @@
;; Predicates for the ZBS extension.
(define_predicate "single_bit_mask_operand"
(and (match_code "const_int")
(match_test "pow2p_hwi (INTVAL (op))")))
(match_test "SINGLE_BIT_MASK_OPERAND (UINTVAL (op))")))

(define_predicate "not_single_bit_mask_operand"
(and (match_code "const_int")
(match_test "pow2p_hwi (~INTVAL (op))")))
(match_test "SINGLE_BIT_MASK_OPERAND (~UINTVAL (op))")))

(define_predicate "const31_operand"
(and (match_code "const_int")
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12 changes: 9 additions & 3 deletions gcc/config/riscv/riscv.cc
Original file line number Diff line number Diff line change
Expand Up @@ -432,7 +432,7 @@ riscv_build_integer_1 (struct riscv_integer_op codes[RISCV_MAX_INTEGER_OPS],
sign-extended (negative) representation (-1 << 31) for the
value, if we want to build (1 << 31) in SImode. This will
then expand to an LUI instruction. */
if (mode == SImode && value == (HOST_WIDE_INT_1U << 31))
if (TARGET_64BIT && mode == SImode && value == (HOST_WIDE_INT_1U << 31))
codes[0].value = (HOST_WIDE_INT_M1U << 31);

return 1;
Expand All @@ -445,7 +445,11 @@ riscv_build_integer_1 (struct riscv_integer_op codes[RISCV_MAX_INTEGER_OPS],
&& (mode != HImode
|| value - low_part <= ((1 << (GET_MODE_BITSIZE (HImode) - 1)) - 1)))
{
alt_cost = 1 + riscv_build_integer_1 (alt_codes, value - low_part, mode);
HOST_WIDE_INT upper_part = value - low_part;
if (mode != VOIDmode)
upper_part = trunc_int_for_mode (value - low_part, mode);

alt_cost = 1 + riscv_build_integer_1 (alt_codes, upper_part, mode);
if (alt_cost < cost)
{
alt_codes[alt_cost-1].code = PLUS;
Expand Down Expand Up @@ -1550,6 +1554,7 @@ riscv_move_integer (rtx temp, rtx dest, HOST_WIDE_INT value,
x = riscv_split_integer (value, mode);
else
{
codes[0].value = trunc_int_for_mode (codes[0].value, mode);
/* Apply each binary operation to X. */
x = GEN_INT (codes[0].value);

Expand All @@ -1559,7 +1564,7 @@ riscv_move_integer (rtx temp, rtx dest, HOST_WIDE_INT value,
x = riscv_emit_set (temp, x);
else
x = force_reg (mode, x);

codes[i].value = trunc_int_for_mode (codes[i].value, mode);
x = gen_rtx_fmt_ee (codes[i].code, mode, x, GEN_INT (codes[i].value));
}
}
Expand Down Expand Up @@ -2651,6 +2656,7 @@ riscv_emit_int_compare (enum rtx_code *code, rtx *op0, rtx *op1)
continue;

new_rhs = rhs + (increment ? 1 : -1);
new_rhs = trunc_int_for_mode (new_rhs, GET_MODE (*op0));
if (riscv_integer_cost (new_rhs) < riscv_integer_cost (rhs)
&& (rhs < 0) == (new_rhs < 0))
{
Expand Down
4 changes: 3 additions & 1 deletion gcc/config/riscv/riscv.h
Original file line number Diff line number Diff line change
Expand Up @@ -535,7 +535,9 @@ enum reg_class
/* If this is a single bit mask, then we can load it with bseti. Special
handling of SImode 0x80000000 on RV64 is done in riscv_build_integer_1. */
#define SINGLE_BIT_MASK_OPERAND(VALUE) \
(pow2p_hwi (VALUE))
(pow2p_hwi (TARGET_64BIT \
? (VALUE) \
: ((VALUE) & ((HOST_WIDE_INT_1U << 32)-1))))

/* Stack layout; function entry, exit and calling. */

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