On 10/18/2017 06:48 AM, Segher Boessenkool wrote:
A volatile asm statement can not be moved (relative to other volatile
asm, etc.), but IRA could do it nevertheless. This patch fixes it.
Testing on powerpc64-linux {-m32,-m64}; okay if it succeeds? Also
for backports?
Although I am not an author of this code, the patch looks ok for me.
ASM_OPERANDS with volatile memory creates a barrier. I guess still a
few such cases are missed for rtx_moveable_p. The reference for such
cases should be function sched_deps.c::sched_analyze.
You can commit it to the trunk and backport. It should be safe.
Segher, thank you for working on the PR.
2017-10-18 Segher Boessenkool <seg...@kernel.crashing.org>
PR rtl-optimization/82602
* ira.c (rtx_moveable_p): Return false for volatile asm.
---
gcc/ira.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/gcc/ira.c b/gcc/ira.c
index 046ce3b..8c93d3d 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -4400,6 +4400,12 @@ rtx_moveable_p (rtx *loc, enum op_type type)
for a reason. */
return false;
+ case ASM_OPERANDS:
+ /* The same is true for volatile asm: it has unknown side effects, it
+ cannot be moved at will. */
+ if (MEM_VOLATILE_P (x))
+ return false;
+
default:
break;
}
