https://gcc.gnu.org/g:6a77bf08e5a5fb1554ff99b231c4a9ae2d3f1149
commit r16-4371-g6a77bf08e5a5fb1554ff99b231c4a9ae2d3f1149 Author: David Faust <[email protected]> Date: Fri Oct 10 10:35:07 2025 -0700 bpf: fix cbranch miscompilation in CPUv1 [PR122141] As diagnosed by Andrew in the linked PR, when reversing the branch condition to work around lack of some cbranch instructions, we must use swap_condition rather than reverse_condition. PR target/122141 gcc/ * config/bpf/bpf.cc (bpf_expand_cbranch): Use swap_condition rather than reverse_condition when reversing jump condition to work around missing instructions in very old BPF ISAs. gcc/testsuite/ * gcc.target/bpf/pr122141-1.c: New. * gcc.target/bpf/pr122141-2.c: New. Suggested-by: Andrew Pinski <[email protected]> Diff: --- gcc/config/bpf/bpf.cc | 2 +- gcc/testsuite/gcc.target/bpf/pr122141-1.c | 11 +++++++++++ gcc/testsuite/gcc.target/bpf/pr122141-2.c | 11 +++++++++++ 3 files changed, 23 insertions(+), 1 deletion(-) diff --git a/gcc/config/bpf/bpf.cc b/gcc/config/bpf/bpf.cc index e9b3fe9d71fc..2e7474be1ff3 100644 --- a/gcc/config/bpf/bpf.cc +++ b/gcc/config/bpf/bpf.cc @@ -444,7 +444,7 @@ bpf_expand_cbranch (machine_mode mode, rtx *operands) if ((code == LT || code == LE || code == LTU || code == LEU)) { /* Reverse the condition. */ - PUT_CODE (operands[0], reverse_condition (code)); + PUT_CODE (operands[0], swap_condition (code)); /* Swap the operands, and ensure that the first is a register. */ if (!register_operand (operands[2], mode)) diff --git a/gcc/testsuite/gcc.target/bpf/pr122141-1.c b/gcc/testsuite/gcc.target/bpf/pr122141-1.c new file mode 100644 index 000000000000..8fd124583795 --- /dev/null +++ b/gcc/testsuite/gcc.target/bpf/pr122141-1.c @@ -0,0 +1,11 @@ +/* PR122141 miscompilation when j(s)l[te] unavailable. */ +/* { dg-do compile } */ +/* { dg-options "-O2 -mcpu=v1 -masm=normal" } */ + +int +f(long a, long b) +{ + return a > b ? 2 : 3; +} + +/* { dg-final { scan-assembler "jsge\t%r2,%r1" } } */ diff --git a/gcc/testsuite/gcc.target/bpf/pr122141-2.c b/gcc/testsuite/gcc.target/bpf/pr122141-2.c new file mode 100644 index 000000000000..3ae16e07d4fa --- /dev/null +++ b/gcc/testsuite/gcc.target/bpf/pr122141-2.c @@ -0,0 +1,11 @@ +/* PR122141 miscompilation when j(s)l[te] unavailable. */ +/* { dg-do compile } */ +/* { dg-options "-O2 -mcpu=v1 -masm=normal" } */ + +int +g(unsigned long a, unsigned long b) +{ + return a >= b ? 4 : 5; +} + +/* { dg-final { scan-assembler "jgt\t%r2,%r1" } } */
