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[RISCV] Fix PR 106586: riscv32 vs ZBS
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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gcc/config/riscv/predicates.md

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -226,11 +226,11 @@
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;; Predicates for the ZBS extension.
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(define_predicate "single_bit_mask_operand"
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(and (match_code "const_int")
229-
(match_test "pow2p_hwi (INTVAL (op))")))
229+
(match_test "SINGLE_BIT_MASK_OPERAND (UINTVAL (op))")))
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(define_predicate "not_single_bit_mask_operand"
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(and (match_code "const_int")
233-
(match_test "pow2p_hwi (~INTVAL (op))")))
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(match_test "SINGLE_BIT_MASK_OPERAND (~UINTVAL (op))")))
234234

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(define_predicate "const31_operand"
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(and (match_code "const_int")

gcc/config/riscv/riscv.cc

Lines changed: 9 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -432,7 +432,7 @@ riscv_build_integer_1 (struct riscv_integer_op codes[RISCV_MAX_INTEGER_OPS],
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sign-extended (negative) representation (-1 << 31) for the
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value, if we want to build (1 << 31) in SImode. This will
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then expand to an LUI instruction. */
435-
if (mode == SImode && value == (HOST_WIDE_INT_1U << 31))
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if (TARGET_64BIT && mode == SImode && value == (HOST_WIDE_INT_1U << 31))
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codes[0].value = (HOST_WIDE_INT_M1U << 31);
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438438
return 1;
@@ -445,7 +445,11 @@ riscv_build_integer_1 (struct riscv_integer_op codes[RISCV_MAX_INTEGER_OPS],
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&& (mode != HImode
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|| value - low_part <= ((1 << (GET_MODE_BITSIZE (HImode) - 1)) - 1)))
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{
448-
alt_cost = 1 + riscv_build_integer_1 (alt_codes, value - low_part, mode);
448+
HOST_WIDE_INT upper_part = value - low_part;
449+
if (mode != VOIDmode)
450+
upper_part = trunc_int_for_mode (value - low_part, mode);
451+
452+
alt_cost = 1 + riscv_build_integer_1 (alt_codes, upper_part, mode);
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if (alt_cost < cost)
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{
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alt_codes[alt_cost-1].code = PLUS;
@@ -1550,6 +1554,7 @@ riscv_move_integer (rtx temp, rtx dest, HOST_WIDE_INT value,
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x = riscv_split_integer (value, mode);
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else
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{
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codes[0].value = trunc_int_for_mode (codes[0].value, mode);
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/* Apply each binary operation to X. */
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x = GEN_INT (codes[0].value);
15551560

@@ -1559,7 +1564,7 @@ riscv_move_integer (rtx temp, rtx dest, HOST_WIDE_INT value,
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x = riscv_emit_set (temp, x);
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else
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x = force_reg (mode, x);
1562-
1567+
codes[i].value = trunc_int_for_mode (codes[i].value, mode);
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x = gen_rtx_fmt_ee (codes[i].code, mode, x, GEN_INT (codes[i].value));
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}
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}
@@ -2651,6 +2656,7 @@ riscv_emit_int_compare (enum rtx_code *code, rtx *op0, rtx *op1)
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continue;
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26532658
new_rhs = rhs + (increment ? 1 : -1);
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new_rhs = trunc_int_for_mode (new_rhs, GET_MODE (*op0));
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if (riscv_integer_cost (new_rhs) < riscv_integer_cost (rhs)
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&& (rhs < 0) == (new_rhs < 0))
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{

gcc/config/riscv/riscv.h

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -535,7 +535,9 @@ enum reg_class
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/* If this is a single bit mask, then we can load it with bseti. Special
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handling of SImode 0x80000000 on RV64 is done in riscv_build_integer_1. */
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#define SINGLE_BIT_MASK_OPERAND(VALUE) \
538-
(pow2p_hwi (VALUE))
538+
(pow2p_hwi (TARGET_64BIT \
539+
? (VALUE) \
540+
: ((VALUE) & ((HOST_WIDE_INT_1U << 32)-1))))
539541

540542
/* Stack layout; function entry, exit and calling. */
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