From: Kalvis Duckmanton <[email protected]>
When cross-compiling itself for VAX, GCC terminates abruptly with an ICE
when compiling gimple_match.cc; the root cause seems to be an
incompletely removed computed jump instruction, which causes the
assertion in cfgrtl.cc around line 4083, to no longer hold.
I have verified that the problem is present in GCC 15.2.0 and believe
that it's also present in trunk (based on the fact that the patterns for
the "casesi1" and "*casesi1" instructions in 15.2.0 and trunk are the
same).
To fix this issue wrap the limit operand in a USE, to allow `single_set'
to identify it as an RTL expression setting PC. This allows the
optimizer to optimize away case statements branching only to a basic
block, removing the ICE.
Include a test case reduced from gimple_match.cc, which demonstrates the
problem in GCC 15.2.0 on NetBSD/amd64 cross-compiling for VAX.
gcc/
PR target/112400
* config/vax/vax.md (casesi1): Wrap naked operand 1 with a USE
where used with the insn split to.
(*casesi1): Likewise naked incoming operand 1.
gcc/testsuite/
PR target/112400
* g++.dg/torture/pr112400.C: New file.
---
gcc/config/vax/vax.md | 4 +-
gcc/testsuite/g++.dg/torture/pr112400.C | 114 ++++++++++++++++++++++++
2 files changed, 116 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/torture/pr112400.C
diff --git a/gcc/config/vax/vax.md b/gcc/config/vax/vax.md
index 9eb831c49f8..71345e4c3ea 100644
--- a/gcc/config/vax/vax.md
+++ b/gcc/config/vax/vax.md
@@ -2909,7 +2909,7 @@ (define_insn_and_split "casesi1"
"#"
"reload_completed"
[(parallel
- [(match_dup 1)
+ [(use (match_dup 1))
(set (pc)
(plus:SI (sign_extend:SI
(mem:HI (plus:SI
@@ -2922,7 +2922,7 @@ (define_insn_and_split "casesi1"
"")
(define_insn "*casesi1"
- [(match_operand:SI 1 "const_int_operand" "n")
+ [(use (match_operand:SI 1 "const_int_operand" "n"))
(set (pc)
(plus:SI (sign_extend:SI
(mem:HI (plus:SI
diff --git a/gcc/testsuite/g++.dg/torture/pr112400.C
b/gcc/testsuite/g++.dg/torture/pr112400.C
new file mode 100644
index 00000000000..b703c80ce73
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr112400.C
@@ -0,0 +1,114 @@
+/* { dg-do compile } */
+/* { dg-options "-Wno-return-type" } */
+
+typedef struct a *b;
+template <typename c, typename d> c e(d);
+enum f { g, h, i };
+enum j { k, l, m, aa };
+struct a {
+ f ab;
+};
+struct af {
+} n;
+struct ah;
+class al;
+b q;
+void r(a *);
+struct o : af {};
+struct p : o {};
+struct ag : p {};
+j s(af *);
+b t();
+f fn4();
+unsigned fn5(ag *);
+b u(ag *, unsigned);
+af *v(b(b), b);
+static bool w(al *, af *, b(b), b aw, b *ax, j) {
+ r(ax[2]);
+ if (aw)
+ return false;
+}
+ag *ay;
+void x(al *at, b as(b), b bb, b bc) {
+ switch (bb->ab)
+ case i:
+ if (af *bd = v(as, bb))
+ if (e<ah *>(bd))
+ switch (fn4())
+ case h: {
+ b be;
+ switch (be->ab)
+ case i:
+ if (af *bf = v(as, be))
+ if (e<ah *>(bf))
+ if (ag *bg = e<ag *>(bf))
+ switch (s(bg)) {
+ case k:
+ if (fn5(bg) == 1) {
+ b bh = u(bg, 0);
+ bh = t();
+ switch (bc->ab)
+ case g: {
+ b ax[]{be, bh, bc};
+ w(at, &n, as, q, ax, k);
+ }
+ }
+ break;
+ case l:
+ if (fn5(bg) == 1) {
+ b bh = u(bg, 0);
+ bh = t();
+ switch (bc->ab)
+ case g: {
+ b ax[]{be, bh, bc};
+ w(at, &n, as, q, ax, l);
+ }
+ }
+ }
+ }
+ else switch (s(ay)) {
+ case k:
+ if (fn5(ay) == 1) {
+ b be = u(ay, 0);
+ be = t();
+ switch (bc->ab)
+ case g: {
+ b ax[]{bb, be, bc};
+ w(at, &n, as, q, ax, k);
+ }
+ }
+ break;
+ case l:
+ if (fn5(ay) == 1) {
+ b be = u(ay, 0);
+ be = t();
+ switch (bc->ab)
+ case g: {
+ b ax[]{bb, be, bc};
+ w(at, &n, as, q, ax, l);
+ }
+ }
+ break;
+ case m:
+ if (fn5(ay) == 1) {
+ b be = u(ay, 0);
+ be = t();
+ switch (bc->ab)
+ case g: {
+ b ax[]{bb, be, bc};
+ w(at, &n, as, q, ax, m);
+ }
+ }
+ break;
+ case aa:
+ if (fn5(ay) == 1) {
+ b be = u(ay, 0);
+ be = t();
+ switch (bc->ab)
+ case g: {
+ b ax[]{bb, be, bc};
+ w(at, &n, as, q, ax, aa);
+ }
+ }
+ }
+}
--
2.20.1
