arm_split_atomic_op handles subtracting a constant by converting it
into addition of the negated constant. But if the type of the operand
is int and the constant is -1 we currently end up generating invalid
RTL which can lead to an abort later on.
The problem is that in a HOST_WIDE_INT, INT_MIN is represented as
0xffffffff80000000 and the negation of this is 0x0000000080000000, but
that's not a valid constant for use in SImode operations.
The fix is straight-forward which is to use gen_int_mode rather than
simply GEN_INT. This knows how to correctly sign-extend the negated
constant when this is needed.
gcc/
PR target/97534
* config/arm/arm.c (arm_split_atomic_op): Use gen_int_mode when
negating a const_int.
gcc/testsuite/
* gcc.dg/pr97534.c: New test.
---
gcc/config/arm/arm.c | 2 +-
gcc/testsuite/gcc.dg/pr97534.c | 9 +++++++++
2 files changed, 10 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/pr97534.c
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 568e1530f24..56ed556b098 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -30824,7 +30824,7 @@ arm_split_atomic_op (enum rtx_code code, rtx old_out,
rtx new_out, rtx mem,
case MINUS:
if (CONST_INT_P (value))
{
- value = GEN_INT (-INTVAL (value));
+ value = gen_int_mode (-INTVAL (value), wmode);
code = PLUS;
}
/* FALLTHRU */
diff --git a/gcc/testsuite/gcc.dg/pr97534.c b/gcc/testsuite/gcc.dg/pr97534.c
new file mode 100644
index 00000000000..b363a322aa5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr97534.c
@@ -0,0 +1,9 @@
+/* PR target/97534 - ICE in decompose on arm*-*-*. */
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -O2 -g" } */
+
+int f (int a)
+{
+ int b;
+ __atomic_fetch_sub(&b, (int)(-__INT_MAX__ - 1), (int)0);
+}
--
2.17.1
