https://gcc.gnu.org/g:f43f346f19889a15a171a10c6ae1b1fe0a5bc038
commit r14-10181-gf43f346f19889a15a171a10c6ae1b1fe0a5bc038
Author: Jakub Jelinek <ja...@redhat.com>
Date: Tue May 7 21:30:21 2024 +0200
expansion: Use __trunchfbf2 calls rather than __extendhfbf2 [PR114907]
The HF and BF modes have the same size/precision and neither is
a subset nor superset of the other.
So, using either __extendhfbf2 or __trunchfbf2 is weird.
The expansion apparently emits __extendhfbf2, but on the libgcc side
we apparently have __trunchfbf2 implemented.
I think it is easier to switch to using what is available rather than
adding new entrypoints to libgcc, even alias, because this is backportable.
2024-05-07 Jakub Jelinek <ja...@redhat.com>
PR middle-end/114907
* expr.cc (convert_mode_scalar): Use trunc_optab rather than
sext_optab for HF->BF conversions.
* optabs-libfuncs.cc (gen_trunc_conv_libfunc): Likewise.
* gcc.dg/pr114907.c: New test.
(cherry picked from commit 28ee13db2e9d995bd3728c4ff3a3545e24b39cd2)
Diff:
---
gcc/expr.cc | 12 ++++++++++--
gcc/optabs-libfuncs.cc | 4 +++-
gcc/testsuite/gcc.dg/pr114907.c | 27 +++++++++++++++++++++++++++
3 files changed, 40 insertions(+), 3 deletions(-)
diff --git a/gcc/expr.cc b/gcc/expr.cc
index d4414e242cb9..9f66d4794459 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -355,8 +355,16 @@ convert_mode_scalar (rtx to, rtx from, int unsignedp)
&& REAL_MODE_FORMAT (from_mode) == &ieee_half_format));
if (GET_MODE_PRECISION (from_mode) == GET_MODE_PRECISION (to_mode))
- /* Conversion between decimal float and binary float, same size. */
- tab = DECIMAL_FLOAT_MODE_P (from_mode) ? trunc_optab : sext_optab;
+ {
+ if (REAL_MODE_FORMAT (to_mode) == &arm_bfloat_half_format
+ && REAL_MODE_FORMAT (from_mode) == &ieee_half_format)
+ /* libgcc implements just __trunchfbf2, not __extendhfbf2. */
+ tab = trunc_optab;
+ else
+ /* Conversion between decimal float and binary float, same
+ size. */
+ tab = DECIMAL_FLOAT_MODE_P (from_mode) ? trunc_optab : sext_optab;
+ }
else if (GET_MODE_PRECISION (from_mode) < GET_MODE_PRECISION (to_mode))
tab = sext_optab;
else
diff --git a/gcc/optabs-libfuncs.cc b/gcc/optabs-libfuncs.cc
index 02e9bf6ea5aa..26729910d92b 100644
--- a/gcc/optabs-libfuncs.cc
+++ b/gcc/optabs-libfuncs.cc
@@ -589,7 +589,9 @@ gen_trunc_conv_libfunc (convert_optab tab,
if (GET_MODE_CLASS (float_tmode) != GET_MODE_CLASS (float_fmode))
gen_interclass_conv_libfunc (tab, opname, float_tmode, float_fmode);
- if (GET_MODE_PRECISION (float_fmode) <= GET_MODE_PRECISION (float_tmode))
+ if (GET_MODE_PRECISION (float_fmode) <= GET_MODE_PRECISION (float_tmode)
+ && (REAL_MODE_FORMAT (float_tmode) != &arm_bfloat_half_format
+ || REAL_MODE_FORMAT (float_fmode) != &ieee_half_format))
return;
if (GET_MODE_CLASS (float_tmode) == GET_MODE_CLASS (float_fmode))
diff --git a/gcc/testsuite/gcc.dg/pr114907.c b/gcc/testsuite/gcc.dg/pr114907.c
new file mode 100644
index 000000000000..628746e1f8c1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr114907.c
@@ -0,0 +1,27 @@
+/* PR middle-end/114907 */
+/* { dg-do run } */
+/* { dg-options "" } */
+/* { dg-add-options float16 } */
+/* { dg-require-effective-target float16_runtime } */
+/* { dg-add-options bfloat16 } */
+/* { dg-require-effective-target bfloat16_runtime } */
+
+__attribute__((noipa)) _Float16
+foo (__bf16 x)
+{
+ return (_Float16) x;
+}
+
+__attribute__((noipa)) __bf16
+bar (_Float16 x)
+{
+ return (__bf16) x;
+}
+
+int
+main ()
+{
+ if (foo (11.125bf16) != 11.125f16
+ || bar (11.125f16) != 11.125bf16)
+ __builtin_abort ();
+}
