https://gcc.gnu.org/g:9ba5c71aeab72bf5a773eaeaaf96a03520c3da9f
commit 9ba5c71aeab72bf5a773eaeaaf96a03520c3da9f
Author: Jeff Law <j...@ventanamicro.com>
Date: Thu May 2 17:13:12 2024 -0600
[committed][RISC-V] Fix nearbyint failure on rv32 and formatting nits
The CI system tripped an execution failure for rv32 with the ceil/round
patch.
The fundamental problem is the FP->INT step in these sequences requires the
input size to match the output size. The output size was based on
rv32/rv64.
Meaning that we'd try to do DF->SI->DF.
That doesn't preserve the semantics we want in at least two ways.
The net is we can't use this trick for DF values on rv32. While inside the
code I realized we had a similar problem for HF modes. HF modes we can
support
only for Zfa. So I fixed that proactively.
The CI system also pointed out various formatting nits. I think this fixes
all
but one overly long line.
Note I could have factored the TARGET_ZFA test. But I think as-written it's
clearer what the desired cases to transform are.
gcc/
* config/riscv/riscv.md (<round_pattern><ANYF:mode>2): Adjust
condition to match what can be properly implemented. Fix various
formatting issues.
(l<round_pattern><ANYF:mode>si2_sext): Fix formatting
(cherry picked from commit 8367c996e55b2c54aeee25e446357a1015a1d11d)
Diff:
---
gcc/config/riscv/riscv.md | 65 +++++++++++++++++++++++++----------------------
1 file changed, 34 insertions(+), 31 deletions(-)
diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
index b9b0acf92c73..d4676507b452 100644
--- a/gcc/config/riscv/riscv.md
+++ b/gcc/config/riscv/riscv.md
@@ -2077,8 +2077,8 @@
(define_insn "l<round_pattern><ANYF:mode>si2_sext"
[(set (match_operand:DI 0 "register_operand" "=r")
(sign_extend:DI (unspec:SI
- [(match_operand:ANYF 1 "register_operand" " f")]
- ROUND)))]
+ [(match_operand:ANYF 1 "register_operand" " f")]
+ ROUND)))]
"TARGET_64BIT && (TARGET_HARD_FLOAT || TARGET_ZFINX)"
"fcvt.w.<ANYF:fmt> %0,%1,<round_rm>"
[(set_attr "type" "fcvt_f2i")
@@ -2094,13 +2094,25 @@
[(set_attr "type" "fcvt_f2i")
(set_attr "mode" "<ANYF:MODE>")])
+;; There are a couple non-obvious restrictions to be aware of.
+;;
+;; We'll do a FP-INT conversion in the sequence. But we don't
+;; have a .l (64bit) variant of those instructions for rv32.
+;; To preserve proper semantics we must reject DFmode inputs
+;; for rv32 unless Zfa is enabled.
+;;
+;; The ANYF iterator allows HFmode. We don't have all the
+;; necessary patterns defined for HFmode. So restrict HFmode
+;; to TARGET_ZFA.
(define_expand "<round_pattern><ANYF:mode>2"
[(set (match_operand:ANYF 0 "register_operand" "=f")
- (unspec:ANYF
- [(match_operand:ANYF 1 "register_operand" " f")]
- ROUND))]
- "TARGET_HARD_FLOAT && (TARGET_ZFA
- || flag_fp_int_builtin_inexact ||
!flag_trapping_math)"
+ (unspec:ANYF
+ [(match_operand:ANYF 1 "register_operand" " f")]
+ ROUND))]
+ "(TARGET_HARD_FLOAT
+ && (TARGET_ZFA || flag_fp_int_builtin_inexact || !flag_trapping_math)
+ && (TARGET_ZFA || TARGET_64BIT || <ANYF:MODE>mode != DFmode)
+ && (TARGET_ZFA || <ANYF:MODE>mode != HFmode))"
{
if (TARGET_ZFA)
emit_insn (gen_<round_pattern><ANYF:mode>_zfa2 (operands[0],
@@ -2116,7 +2128,7 @@
riscv_emit_move (tmp_reg, operands[1]);
riscv_emit_move (coeff_reg,
- riscv_vector::get_fp_rounding_coefficient
(<ANYF:MODE>mode));
+ riscv_vector::get_fp_rounding_coefficient
(<ANYF:MODE>mode));
emit_insn (gen_abs<ANYF:mode>2 (abs_reg, operands[1]));
riscv_expand_conditional_branch (label, LT, abs_reg, coeff_reg);
@@ -2126,29 +2138,20 @@
emit_label (label);
switch (<ANYF:MODE>mode)
- {
- case SFmode:
- reg = gen_reg_rtx (SImode);
- emit_insn (gen_l<round_pattern>sfsi2 (reg, operands[1]));
- emit_insn (gen_floatsisf2 (abs_reg, reg));
- break;
- case DFmode:
- if (TARGET_64BIT)
- {
- reg = gen_reg_rtx (DImode);
- emit_insn (gen_l<round_pattern>dfdi2 (reg, operands[1]));
- emit_insn (gen_floatdidf2 (abs_reg, reg));
- }
- else
- {
- reg = gen_reg_rtx (SImode);
- emit_insn (gen_l<round_pattern>dfsi2 (reg, operands[1]));
- emit_insn (gen_floatsidf2 (abs_reg, reg));
- }
- break;
- default:
- gcc_unreachable ();
- }
+ {
+ case SFmode:
+ reg = gen_reg_rtx (SImode);
+ emit_insn (gen_l<round_pattern>sfsi2 (reg, operands[1]));
+ emit_insn (gen_floatsisf2 (abs_reg, reg));
+ break;
+ case DFmode:
+ reg = gen_reg_rtx (DImode);
+ emit_insn (gen_l<round_pattern>dfdi2 (reg, operands[1]));
+ emit_insn (gen_floatdidf2 (abs_reg, reg));
+ break;
+ default:
+ gcc_unreachable ();
+ }
emit_insn (gen_copysign<ANYF:mode>3 (tmp_reg, abs_reg, operands[1]));
