https://gcc.gnu.org/g:2ec5082dd24cef5149ba645ee88a9acd8b4c290a
commit r16-727-g2ec5082dd24cef5149ba645ee88a9acd8b4c290a
Author: Jennifer Schmitz <jschm...@nvidia.com>
Date: Thu May 15 07:16:15 2025 -0700
regcprop: Return from copy_value for unordered modes
The ICE in PR120276 resulted from a comparison of VNx4QI and V8QI using
partial_subreg_p in the function copy_value during the RTL pass
regcprop, failing the assertion in
inline bool
partial_subreg_p (machine_mode outermode, machine_mode innermode)
{
/* Modes involved in a subreg must be ordered. In particular, we must
always know at compile time whether the subreg is paradoxical. */
poly_int64 outer_prec = GET_MODE_PRECISION (outermode);
poly_int64 inner_prec = GET_MODE_PRECISION (innermode);
gcc_checking_assert (ordered_p (outer_prec, inner_prec));
return maybe_lt (outer_prec, inner_prec);
}
Returning from the function if the modes are not ordered before reaching
the call to partial_subreg_p resolves the ICE and passes bootstrap and
testing without regression.
OK for mainline?
Signed-off-by: Jennifer Schmitz <jschm...@nvidia.com>
gcc/
PR middle-end/120276
* regcprop.cc (copy_value): Return in case of unordered modes.
gcc/testsuite/
PR middle-end/120276
* gcc.dg/torture/pr120276.c: New test.
Diff:
---
gcc/regcprop.cc | 4 ++++
gcc/testsuite/gcc.dg/torture/pr120276.c | 20 ++++++++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/gcc/regcprop.cc b/gcc/regcprop.cc
index 4fa1305526cc..98ab3f77e835 100644
--- a/gcc/regcprop.cc
+++ b/gcc/regcprop.cc
@@ -332,6 +332,10 @@ copy_value (rtx dest, rtx src, struct value_data *vd)
if (vd->e[sr].mode == VOIDmode)
set_value_regno (sr, vd->e[dr].mode, vd);
+ else if (!ordered_p (GET_MODE_PRECISION (vd->e[sr].mode),
+ GET_MODE_PRECISION (GET_MODE (src))))
+ return;
+
/* If we are narrowing the input to a smaller number of hard regs,
and it is in big endian, we are really extracting a high part.
Since we generally associate a low part of a value with the value itself,
diff --git a/gcc/testsuite/gcc.dg/torture/pr120276.c
b/gcc/testsuite/gcc.dg/torture/pr120276.c
new file mode 100644
index 000000000000..9717a7103e5e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr120276.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-march=armv8.2-a+sve" { target aarch64*-*-* } } */
+
+int a;
+char b[1];
+int c[18];
+void d(char *);
+void e() {
+ int f;
+ char *g;
+ a = 0;
+ for (; a < 18; a++) {
+ int h = f = 0;
+ for (; f < 4; f++) {
+ g[a * 4 + f] = c[a] >> h;
+ h += 8;
+ }
+ }
+ d(b);
+}
\ No newline at end of file
