https://gcc.gnu.org/g:fb6ec6df54317ed3f6e6f878b6ea29dbef6bfe2d
commit r13-8598-gfb6ec6df54317ed3f6e6f878b6ea29dbef6bfe2d
Author: Kito Cheng <kito.ch...@sifive.com>
Date: Wed Feb 28 16:01:52 2024 +0800
RISC-V: Fix __atomic_compare_exchange with 32 bit value on RV64
atomic_compare_and_swapsi will use lr.w to do obtain the original value,
which sign extends to DI. RV64 only has DI comparisons, so we also need
to sign extend the expected value to DI as otherwise the comparison will
fail when the expected value has the 32nd bit set.
gcc/ChangeLog:
PR target/114130
* config/riscv/sync.md (atomic_compare_and_swap<mode>): Sign
extend the expected value if needed.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/pr114130.c: New.
Reviewed-by: Palmer Dabbelt <pal...@rivosinc.com>
(cherry picked from commit fd07a29e39f5347d6cef3e7042a32306f97a1719)
Diff:
---
gcc/config/riscv/sync.md | 9 +++++++++
gcc/testsuite/gcc.target/riscv/pr114130.c | 12 ++++++++++++
2 files changed, 21 insertions(+)
diff --git a/gcc/config/riscv/sync.md b/gcc/config/riscv/sync.md
index 9fc626267de..9fbd89d7cc8 100644
--- a/gcc/config/riscv/sync.md
+++ b/gcc/config/riscv/sync.md
@@ -383,6 +383,15 @@
(match_operand:SI 7 "const_int_operand" "")] ;; mod_f
"TARGET_ATOMIC"
{
+ if (word_mode != <MODE>mode && operands[3] != const0_rtx)
+ {
+ /* We don't have SI mode compare on RV64, so we need to make sure
expected
+ value is sign-extended. */
+ rtx tmp0 = gen_reg_rtx (word_mode);
+ emit_insn (gen_extend_insn (tmp0, operands[3], word_mode, <MODE>mode,
0));
+ operands[3] = simplify_gen_subreg (<MODE>mode, tmp0, word_mode, 0);
+ }
+
emit_insn (gen_atomic_cas_value_strong<mode> (operands[1], operands[2],
operands[3], operands[4],
operands[6], operands[7]));
diff --git a/gcc/testsuite/gcc.target/riscv/pr114130.c
b/gcc/testsuite/gcc.target/riscv/pr114130.c
new file mode 100644
index 00000000000..cd0a4e8236c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/pr114130.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gc -mabi=lp64 -O" } */
+#include <stdint-gcc.h>
+
+void foo(uint32_t *p) {
+ uintptr_t x = *(uintptr_t *)p;
+ uint32_t e = !p ? 0 : (uintptr_t)p >> 1;
+ uint32_t d = (uintptr_t)x;
+ __atomic_compare_exchange(p, &e, &d, 0, __ATOMIC_RELAXED,
__ATOMIC_RELAXED);
+}
+
+/* { dg-final { scan-assembler-times "sext.w\t" 1 } } */
