From f30a9a8d9e06ae2bf38e0d25e3ca6095212c78e9 Mon Sep 17 00:00:00 2001 From: Richard Earnshaw Date: Tue, 24 Nov 2020 16:21:17 +0000 Subject: [PATCH] arm: correctly handle negating INT_MIN in arm_split_atomic_op [PR97534] 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); +} -- 2.30.2