[PATCH] aarch64: Prevent moving throwing accesses in ldp/stp pass [PR113093]

[Alex Coplan]

As the PR shows, there was nothing to prevent the ldp/stp pass from
trying to move throwing insns, which lead to an RTL verification
failure.

This patch fixes that.

Bootstrapped/regtested on aarch64-linux-gnu, OK for trunk?

Thanks,
Alex

gcc/ChangeLog:

        PR target/113093
        * config/aarch64/aarch64-ldp-fusion.cc (latest_hazard_before):
        If the insn is throwing, record the previous insn as a hazard to
        prevent moving it from the end of the BB.

gcc/testsuite/ChangeLog:

        PR target/113093
        * gcc.dg/pr113093.c: New test.

diff --git a/gcc/config/aarch64/aarch64-ldp-fusion.cc 
b/gcc/config/aarch64/aarch64-ldp-fusion.cc
index 0e2c299a0bf..59db70e9cd0 100644
--- a/gcc/config/aarch64/aarch64-ldp-fusion.cc
+++ b/gcc/config/aarch64/aarch64-ldp-fusion.cc
@@ -618,6 +618,13 @@ latest_hazard_before (insn_info *insn, rtx *ignore,
 {
   insn_info *result = nullptr;
 
+  // If the insn can throw then it is at the end of a BB and we can't
+  // move it, model this by recording a hazard in the previous insn
+  // which will prevent moving the insn up.
+  if (cfun->can_throw_non_call_exceptions
+      && find_reg_note (insn->rtl (), REG_EH_REGION, NULL_RTX))
+    return insn->prev_nondebug_insn ();
+
   // Return true if we registered the hazard.
   auto hazard = [&](insn_info *h) -> bool
     {
diff --git a/gcc/testsuite/gcc.dg/pr113093.c b/gcc/testsuite/gcc.dg/pr113093.c
new file mode 100644
index 00000000000..af2a334b45d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr113093.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-options "-Os -fharden-control-flow-redundancy -fnon-call-exceptions" } 
*/
+_Complex long *c;
+void init() { *c = 1.0; }