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| author | Hongyu Wang <hongyu.wang@intel.com> | 2021-11-18 14:45:23 +0800 |
|---|---|---|
| committer | Hongyu Wang <hongyu.wang@intel.com> | 2021-11-18 16:29:19 +0800 |
| commit | 15f5e70cbb33b40c97325ef9d55557747a148d39 (patch) | |
| tree | 1df1020b51e959c0aa2de8fea18561d3a6161780 /gcc | |
| parent | 17da2c7425ea1f5bf417b954f444dbe1f1618a1c (diff) | |
| download | gcc-15f5e70cbb33b40c97325ef9d55557747a148d39.zip gcc-15f5e70cbb33b40c97325ef9d55557747a148d39.tar.gz gcc-15f5e70cbb33b40c97325ef9d55557747a148d39.tar.bz2 | |
i386: Fix wrong codegen for -mrelax-cmpxchg-loop
For -mrelax-cmpxchg-loop introduced by PR 103069/r12-5265, it would
produce infinite loop. The correct code should be
.L84:
movl (%rdi), %ecx
movl %eax, %edx
orl %esi, %edx
cmpl %eax, %ecx
jne .L82
lock cmpxchgl %edx, (%rdi)
jne .L84
movl %r8d, %eax <<< retval is missing in previous impl
ret
.L82:
rep nop
jmp .L84
Adjust corresponding expander to fix such issue, and fix runtime test
so the problem would be exposed.
gcc/ChangeLog:
* config/i386/i386-expand.c (ix86_expand_atomic_fetch_op_loop):
Adjust generated cfg to avoid infinite loop.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr103069-2.c: Adjust.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/i386/i386-expand.c | 7 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/pr103069-2.c | 11 |
2 files changed, 12 insertions, 6 deletions
diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c index 3e4de64..0d5d1a0 100644 --- a/gcc/config/i386/i386-expand.c +++ b/gcc/config/i386/i386-expand.c @@ -23143,13 +23143,14 @@ void ix86_expand_atomic_fetch_op_loop (rtx target, rtx mem, rtx val, bool doubleword) { rtx old_reg, new_reg, old_mem, success, oldval, new_mem; - rtx_code_label *loop_label, *pause_label; + rtx_code_label *loop_label, *pause_label, *done_label; machine_mode mode = GET_MODE (target); old_reg = gen_reg_rtx (mode); new_reg = old_reg; loop_label = gen_label_rtx (); pause_label = gen_label_rtx (); + done_label = gen_label_rtx (); old_mem = copy_to_reg (mem); emit_label (loop_label); emit_move_insn (old_reg, old_mem); @@ -23207,11 +23208,15 @@ void ix86_expand_atomic_fetch_op_loop (rtx target, rtx mem, rtx val, GET_MODE (success), 1, loop_label, profile_probability::guessed_never ()); + emit_jump_insn (gen_jump (done_label)); + emit_barrier (); + /* If mem is not expected, pause and loop back. */ emit_label (pause_label); emit_insn (gen_pause ()); emit_jump_insn (gen_jump (loop_label)); emit_barrier (); + emit_label (done_label); } #include "gt-i386-expand.h" diff --git a/gcc/testsuite/gcc.target/i386/pr103069-2.c b/gcc/testsuite/gcc.target/i386/pr103069-2.c index 8ac824c..b3f2235 100644 --- a/gcc/testsuite/gcc.target/i386/pr103069-2.c +++ b/gcc/testsuite/gcc.target/i386/pr103069-2.c @@ -1,5 +1,5 @@ -/* PR target/103068 */ -/* { dg-do compile } */ +/* PR target/103069 */ +/* { dg-do run } */ /* { dg-additional-options "-O2 -march=x86-64 -mtune=generic" } */ #include <stdlib.h> @@ -37,13 +37,14 @@ FUNC_ATOMIC_RELAX (char, xor) #define TEST_ATOMIC_FETCH_LOGIC(TYPE, OP) \ { \ TYPE a = 11, b = 101, res, exp; \ + TYPE c = 11, d = 101; \ res = relax_##TYPE##_##OP##_fetch (&a, b); \ - exp = f_##TYPE##_##OP##_fetch (&a, b); \ + exp = f_##TYPE##_##OP##_fetch (&c, d); \ if (res != exp) \ abort (); \ - a = 21, b = 92; \ + a = c = 21, b = d = 92; \ res = relax_##TYPE##_fetch_##OP (&a, b); \ - exp = f_##TYPE##_fetch_##OP (&a, b); \ + exp = f_##TYPE##_fetch_##OP (&c, d); \ if (res != exp) \ abort (); \ } |