On Wed, 16 Sep 2026, liuhongt wrote:
> cond_expr_convert_p used TYPE_SIZE to compare the selected operands.
> For _BitInt this could build a COND_EXPR with arms of different
> precision and ICE in range analysis.
>
> Require equal precision for _BitInt arms. Reject padded comparison
> operands and padded inputs to conditional conversions.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> Ok for trunk?
I think this can happen for non-BitInt INTEGER_TYPE as well, so
the checks should be done for all INTEGRAL_TYPE_P
Richard.
> gcc/ChangeLog:
>
> PR tree-optimization/127382
> * match.pd (cond_expr_convert_p): Check _BitInt precision and reject
> unsupported padded operands.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/bitint-143.c: New test.
> * gcc.dg/bitint-144.c: Ditto.
> * gcc.target/i386/pr127382.c: Ditto.
> ---
> gcc/match.pd | 18 +++++++++++++++++
> gcc/testsuite/gcc.dg/bitint-143.c | 20 +++++++++++++++++++
> gcc/testsuite/gcc.dg/bitint-144.c | 19 ++++++++++++++++++
> gcc/testsuite/gcc.target/i386/pr127382.c | 25 ++++++++++++++++++++++++
> 4 files changed, 82 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/bitint-143.c
> create mode 100644 gcc/testsuite/gcc.dg/bitint-144.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr127382.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 4059ed787f0..2e0077706c8 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -13140,6 +13140,15 @@ and,
> TYPE_SIZE (TREE_TYPE (@2)))
> && operand_equal_p (TYPE_SIZE (TREE_TYPE (@0)),
> TYPE_SIZE (TREE_TYPE (@3)))
> + /* Vector comparisons cannot ignore padding bits. */
> + && (!BITINT_TYPE_P (TREE_TYPE (@0))
> + || type_has_mode_precision_p (TREE_TYPE (@0)))
> + /* @2 and @3 become the COND_EXPR arms. If either is a _BitInt,
> + require equal precision and require @2 to have mode precision. */
> + && (!(BITINT_TYPE_P (TREE_TYPE (@2)) || BITINT_TYPE_P (TREE_TYPE
> (@3)))
> + || (TYPE_PRECISION (TREE_TYPE (@2))
> + == TYPE_PRECISION (TREE_TYPE (@3))
> + && type_has_mode_precision_p (TREE_TYPE (@2))))
> /* For vect_recog_cond_expr_convert_pattern, @2 and @3 can differ in
> signess when convert is truncation, but not ok for extension since
> it's sign_extend vs zero_extend. */
> @@ -13160,6 +13169,9 @@ and,
> && !operand_equal_p (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (@0)))
> && operand_equal_p (TYPE_SIZE (TREE_TYPE (@0)),
> TYPE_SIZE (TREE_TYPE (@2)))
> + && (!BITINT_TYPE_P (TREE_TYPE (@0))
> + || type_has_mode_precision_p (TREE_TYPE (@0)))
> + && type_has_mode_precision_p (TREE_TYPE (@2))
> && single_use (@4)
> && single_use (@5))))
>
> @@ -13174,6 +13186,8 @@ and,
> TYPE_SIZE (TREE_TYPE (@0)))
> && operand_equal_p (TYPE_SIZE (TREE_TYPE (@0)),
> TYPE_SIZE (TREE_TYPE (@2)))
> + && (!BITINT_TYPE_P (TREE_TYPE (@0))
> + || type_has_mode_precision_p (TREE_TYPE (@0)))
> && single_use (@4)
> && single_use (@5))))
>
> @@ -13188,6 +13202,8 @@ and,
> TYPE_SIZE (TREE_TYPE (@0)))
> && operand_equal_p (TYPE_SIZE (TREE_TYPE (@0)),
> TYPE_SIZE (TREE_TYPE (@3)))
> + && (!BITINT_TYPE_P (TREE_TYPE (@0))
> + || type_has_mode_precision_p (TREE_TYPE (@0)))
> && single_use (@5)
> && (flag_unsafe_math_optimizations
> || exact_real_truncate (TYPE_MODE (TREE_TYPE (@3)),
> @@ -13203,6 +13219,8 @@ and,
> && !operand_equal_p (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (@0)))
> && operand_equal_p (TYPE_SIZE (TREE_TYPE (@0)),
> TYPE_SIZE (TREE_TYPE (@2)))
> + && (!BITINT_TYPE_P (TREE_TYPE (@0))
> + || type_has_mode_precision_p (TREE_TYPE (@0)))
> && single_use (@4)
> && (flag_unsafe_math_optimizations
> || exact_real_truncate (TYPE_MODE (TREE_TYPE (@2)),
> diff --git a/gcc/testsuite/gcc.dg/bitint-143.c
> b/gcc/testsuite/gcc.dg/bitint-143.c
> new file mode 100644
> index 00000000000..c461974d323
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/bitint-143.c
> @@ -0,0 +1,20 @@
> +/* PR tree-optimization/127382 */
> +/* { dg-do compile { target bitint } } */
> +/* { dg-options "-O2" } */
> +
> +#if __BITINT_MAXWIDTH__ >= 65
> +_BitInt(7) m0[8];
> +unsigned _BitInt(17) g1;
> +_BitInt(7) p0;
> +
> +void
> +foo (int s0)
> +{
> + p0 = g1;
> + for (unsigned i = 0; i < 7; i++)
> + {
> + _BitInt(65) tt = -(_BitInt(65)) (s0 ? i : g1);
> + m0[i & 7] = tt / 10;
> + }
> +}
> +#endif
> diff --git a/gcc/testsuite/gcc.dg/bitint-144.c
> b/gcc/testsuite/gcc.dg/bitint-144.c
> new file mode 100644
> index 00000000000..555ac75dc21
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/bitint-144.c
> @@ -0,0 +1,19 @@
> +/* PR tree-optimization/127382 */
> +/* { dg-do compile { target bitint } } */
> +/* { dg-options "-O3" } */
> +
> +/* This used to ICE during vectorization. */
> +
> +#if __BITINT_MAXWIDTH__ >= 17
> +_BitInt(17) g[256];
> +unsigned int a[256];
> +int b[256];
> +short d[256];
> +
> +void
> +foo (void)
> +{
> + for (int i = 0; i < 256; i++)
> + d[i] = g[i] < 5wb ? (short) a[i] : (short) b[i];
> +}
> +#endif
> diff --git a/gcc/testsuite/gcc.target/i386/pr127382.c
> b/gcc/testsuite/gcc.target/i386/pr127382.c
> new file mode 100644
> index 00000000000..edf2ebf688f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr127382.c
> @@ -0,0 +1,25 @@
> +/* PR tree-optimization/127382 */
> +/* { dg-do compile { target bitint } } */
> +/* { dg-options "-march=x86-64-v4 -O3 -fdump-tree-vect-details" } */
> +
> +/* A bit-precise type whose precision fills its container is as good as the
> + plain integer type of the same width, so cond_expr_convert_p has to keep
> + matching it, no mask packing. */
> +
> +/* { dg-final { scan-tree-dump "vect_recog_cond_expr_convert_pattern" "vect"
> { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler-not "kshift" { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler-not "kunpck" { target { ! ia32 } } } } */
> +
> +#if __BITINT_MAXWIDTH__ >= 32
> +_BitInt(32) a[256];
> +int b[256];
> +short d[256];
> +float c[256];
> +
> +void
> +foo (void)
> +{
> + for (int i = 0; i < 256; i++)
> + d[i] = c[i] < 1.0f ? (short) a[i] : (short) b[i];
> +}
> +#endif
>
--
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Stefan Gaiser, Jochen Jaser, Abhinav Puri; (HRB 36809, AG Nuernberg)
