Hi,
this patch fixes PR66444, a problem with -fipa-ra in reload_combine.
The problem is that for the test-case, reload_combine combines these two
insns:
...
(insn 13 12 14 2 (parallel [
(set (reg/v/f:DI 37 r8 [orig:92 xD.1858 ] [92])
(plus:DI (reg:DI 37 r8 [96])
(reg:DI 0 ax [orig:95 D.1884 ] [95])))
(clobber (reg:CC 17 flags))
])
(expr_list:REG_EQUAL (plus:DI (reg:DI 0 ax [orig:95 D.1884 ] [95])
(const_int 962072674304 [0xe000000000]))
(nil)))
(insn 14 13 15 2 (set (reg:DI 5 di)
(reg/v/f:DI 37 r8 [orig:92 xD.1858 ] [92]))
(nil))
...
into this insn:
...
(insn 14 12 15 2 (set (reg:DI 5 di)
(plus:DI (reg:DI 37 r8 [96])
(reg:DI 0 ax [orig:95 D.1884 ] [95])))
(nil))
...
That removes the set of r8 by insn 13. And that set of r8 is used by
insn 16:
....
(call_insn 15 ...)
(insn 16 15 17 2 (set (reg:DI 5 di)
(reg/v/f:DI 37 r8 [orig:92 x ] [92])) test.c:33 85 {*movdi_internal}
(nil))
...
But reload_combine doesn't acknowledge that use, because it considers
that r8 is killed by call_insn 15.
The patch fixes the problem by using get_call_reg_set_usage to find out
that r8 is actually not killed by the call_insn.
Bootstrapped and reg-tested on x86_64 on top of trunk.
OK for trunk and gcc-5-branch?
Thanks,
- Tom
Handle -fipa-ra in reload_combine
2015-06-08 Tom de Vries <t...@codesourcery.com>
PR rtl-optimization/66444
* postreload.c (reload_combine): Use get_call_reg_set_usage instead of
call_used_regs.
* gcc.dg/pr66444.c: New test.
---
gcc/postreload.c | 5 +++-
gcc/testsuite/gcc.dg/pr66444.c | 58 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 62 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/pr66444.c
diff --git a/gcc/postreload.c b/gcc/postreload.c
index 7ecca15..1cc7b14 100644
--- a/gcc/postreload.c
+++ b/gcc/postreload.c
@@ -1352,9 +1352,12 @@ reload_combine (void)
if (CALL_P (insn))
{
rtx link;
+ HARD_REG_SET used_regs;
+
+ get_call_reg_set_usage (insn, &used_regs, call_used_reg_set);
for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
- if (call_used_regs[r])
+ if (TEST_HARD_REG_BIT (used_regs, r))
{
reg_state[r].use_index = RELOAD_COMBINE_MAX_USES;
reg_state[r].store_ruid = reload_combine_ruid;
diff --git a/gcc/testsuite/gcc.dg/pr66444.c b/gcc/testsuite/gcc.dg/pr66444.c
new file mode 100644
index 0000000..93a7644
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr66444.c
@@ -0,0 +1,58 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fipa-ra" } */
+
+extern void abort (void);
+
+int __attribute__((noinline, noclone))
+bar (void)
+{
+ return 1;
+}
+
+struct S
+{
+ unsigned long p, q, r;
+ void *v;
+};
+
+struct S *s1;
+struct S *s2;
+
+void __attribute__((noinline, noclone))
+fn2 (struct S *x)
+{
+ s2 = x;
+}
+
+__attribute__((noinline, noclone)) void *
+fn1 (struct S *x)
+{
+ /* Just a statement to make it a non-const function. */
+ s1 = x;
+
+ return (void *)0;
+}
+
+int __attribute__((noinline, noclone))
+baz (void)
+{
+ struct S *x = (struct S *) 0xe0000000U;
+
+ x += bar ();
+
+ fn1 (x);
+ fn2 (x);
+
+ return 0;
+}
+
+int
+main (void)
+{
+ baz ();
+
+ if (s2 != (((struct S *) 0xe0000000U) + 1))
+ abort ();
+
+ return 0;
+}
--
1.9.1
