diff mbox

patch to fix PR65647

Message ID CAD57uCfD3i8jRFU4cwyFcfCxX8eKB30qojKwxBJQCYcZeSFpyw@mail.gmail.com
State New
Headers show

Commit Message

Yvan Roux April 5, 2015, 8:45 a.m. UTC 
Hi,

The issue is also present in 4.9 branch as explained in:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65647

As 4.9 doesn't contains lra rematerialization passe, we only need to
stop updating lra_constraint_new_regno_start when inheritance is
switched off.

Bootstrapped and tested on x64_64 and cross built and tested on
AArch64, arm, armeb and i686. Ok for 4.9 ?

Cheers,
Yvan

2015-04-05  Yvan Roux  <yvan.roux@linaro.org>

        Backport from trunk r221867
        2015-04-04  Vladimir Makarov  <vmakarov@redhat.com>

        PR target/65647
        * lra.c (lra): Stop updating lra_constraint_new_regno_start after
          switching off inheritance.

2015-04-05  Yvan Roux  <yvan.roux@linaro.org>

        Backport from trunk r221867
        2015-04-04  Vladimir Makarov  <vmakarov@redhat.com>

        PR target/65647
        * gcc.target/arm/pr65647.c: New.
        * gcc.target/arm/pr65647-2.c: New.

On 4 April 2015 at 16:39, Vladimir Makarov <vmakarov@redhat.com> wrote:
>   The following patch fixes
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65647
>
>   This very complicated problem occurred in rare cases when chain of reloads
> involving at least two pseudos and insns were generated and one pseudo was
> spilled on later sub-passes after spilling sub-pass and this pattern
> happened to be repeated.
>
>   The patch was bootstrapped and tested on x86/x86-64, ppc64, and aarch64.
>
>   Committed as rev.221867.
>
> 2015-04-04  Vladimir Makarov  <vmakarov@redhat.com>
>
>         PR target/65647
>         * lra-int.h (LRA_MAX_REMATERIALIZATION_PASSES): New.  Add its
>         value checking.
>         (lra_rematerialization_iter): New.
>         * lra.c (lra): Initialize lra_rematerialization_iter.
>         Stop updating lra_constraint_new_regno_start after switching of
>         inheritance and rematerialization.
>         * lra-remat.c (lra_rematerialization_iter): New.
>         (lra_remat): Add printing pass iteration.  Do rematerialization
>         only first LRA_MAX_REMATERIALIZATION_PASSES iterations.
>
> 2015-04-04  Vladimir Makarov  <vmakarov@redhat.com>
>
>         PR target/65647
>         * gcc.target/arm/pr65647.c: New.
>
>
diff mbox

Patch

diff --git a/gcc/lra.c b/gcc/lra.c
index 69b08dc..98f0444 100644
--- a/gcc/lra.c
+++ b/gcc/lra.c
@@ -2417,7 +2417,11 @@  lra (FILE *f)
       /* Assignment of stack slots changes elimination offsets for
 	 some eliminations.  So update the offsets here.  */
       lra_eliminate (false, false);
-      lra_constraint_new_regno_start = max_reg_num ();
+      /* After switching off inheritance passe, don't forget reload pseudos
+         after spilling sub-pass to avoid LRA cycling in some complicated
+	 cases.  */
+      if (lra_inheritance_iter <= LRA_MAX_INHERITANCE_PASSES)
+        lra_constraint_new_regno_start = max_reg_num ();
       lra_constraint_new_insn_uid_start = get_max_uid ();
       lra_assignment_iter_after_spill = 0;
     }
diff --git a/gcc/testsuite/gcc.target/arm/pr65647-2.c b/gcc/testsuite/gcc.target/arm/pr65647-2.c
new file mode 100644
index 0000000..f2985f8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr65647-2.c
@@ -0,0 +1,32 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O3 -marm -march=armv6 -std=c99" } */
+
+typedef struct {
+  int i;
+} x264_union32_t;
+typedef struct {
+  int level_idx;
+} trellis_node_t;
+int a, c, d, f, h, i = (int)&c;
+trellis_node_t b[1][1];
+short *e = 0;
+short g;
+void fn1() {
+  int k[64 * 8 * 2];
+  trellis_node_t *l = b[0];
+  for (; i >= d; i--) {
+    if (e[i]) {
+      for (int j = 1; j < 8; j++) {
+        ((x264_union32_t *)&k[a])->i = l[j].level_idx;
+        l[j].level_idx = a;
+        a++;
+      }
+      continue;
+    }
+    for (int j;; j++)
+      ;
+  }
+  int m[6] __attribute__((aligned(16)));
+  for (; h; h++, f++)
+    g = m[h];
+}
diff --git a/gcc/testsuite/gcc.target/arm/pr65647.c b/gcc/testsuite/gcc.target/arm/pr65647.c
new file mode 100644
index 0000000..686eb58
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr65647.c
@@ -0,0 +1,58 @@ 
+/* { dg-do compile } */
+/* { dg-options "-march=armv6-m -mthumb -O3 -w" } */
+
+a, b, c, e, g = &e, h, i = 7, l = 1, m, n, o, q = &m, r, s = &r, u, w = 9, x,
+  y = 6, z, t6 = 7, t8, t9 = 1, t11 = 5, t12 = &t8, t13 = 3, t15,
+  t16 = &t15;
+struct {
+  long long f3;
+    char f4
+} p = {3}
+
+    ,
+  t = {4};
+
+struct S1 {
+  long long f0;
+  short f1;
+    long long f2
+} d;
+long long f = 4073709551613, t7 = 8, t14 = 4073709551610;
+j[];
+k = j;
+v = &d;
+*t10 = j;
+struct S1 fn1();
+struct S1 fn2() {
+  signed char t1;
+  struct S1 t2;
+  long t3 = x;
+  short t4 = h;
+  short *t5 = &l;
+  fn1(t2, w, 1, o);
+  if (u) {
+    l = q;
+    t1 = a < b ?: b;
+    z = c >= 2 || t1 << c;
+  }
+  *t5 = t4 &= t3;
+  fn3(y);
+}
+
+fn4() {
+  t6 = t.f3;
+  fn5(k, t7);
+}
+
+struct S1 fn1() {
+  f = 0;
+  for (; i;)
+    ;
+  t11 = 0;
+  t13 = *t10 = t14 || n;
+  t9 = t12;
+  for (; p.f4;)
+    s = t16 <= fn6();
+  if (g)
+    v = 0;
+}