[PATCH] sel-sched: Verify change before replacing dest in EXPR_INSN_RTX [PR112995]

[Kewen.Lin]

Hi,

PR112995 exposed one issue in current try_replace_dest_reg
that the result rtx insn after replace_dest_with_reg_in_expr
is probably unable to match any constraints.  Although there
are some checks on the changes onto dest or src of orig_insn,
none is performed on the EXPR_INSN_RTX.

This patch is to add the check before actually replacing dest
in expr with reg.

Bootstrapped and regtested on x86_64-redhat-linux and
powerpc64{,le}-linux-gnu.

Is it ok for trunk?

BR,
Kewen
-----
        PR rtl-optimization/112995

gcc/ChangeLog:

        * sel-sched.cc (try_replace_dest_reg): Check the validity of the
        replaced insn before actually replacing dest in expr.

gcc/testsuite/ChangeLog:

        * gcc.target/powerpc/pr112995.c: New test.
---
 gcc/sel-sched.cc                            | 10 +++++++++-
 gcc/testsuite/gcc.target/powerpc/pr112995.c | 14 ++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr112995.c

diff --git a/gcc/sel-sched.cc b/gcc/sel-sched.cc
index 1925f4a9461..a35b5e16c91 100644
--- a/gcc/sel-sched.cc
+++ b/gcc/sel-sched.cc
@@ -1614,7 +1614,15 @@ try_replace_dest_reg (ilist_t orig_insns, rtx best_reg, 
expr_t expr)
   /* Make sure that EXPR has the right destination
      register.  */
   if (expr_dest_regno (expr) != REGNO (best_reg))
-    replace_dest_with_reg_in_expr (expr, best_reg);
+    {
+      rtx_insn *vinsn = EXPR_INSN_RTX (expr);
+      validate_change (vinsn, &SET_DEST (PATTERN (vinsn)), best_reg, 1);
+      bool res = verify_changes (0);
+      cancel_changes (0);
+      if (!res)
+       return false;
+      replace_dest_with_reg_in_expr (expr, best_reg);
+    }
   else
     EXPR_TARGET_AVAILABLE (expr) = 1;

diff --git a/gcc/testsuite/gcc.target/powerpc/pr112995.c 
b/gcc/testsuite/gcc.target/powerpc/pr112995.c
new file mode 100644
index 00000000000..4adcb5f3851
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr112995.c
@@ -0,0 +1,14 @@
+/* { dg-require-effective-target float128 } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9 -fselective-scheduling2" } */
+
+/* Verify there is no ICE.  */
+
+int a[10];
+int b(_Float128 e) {
+  int c;
+  _Float128 d;
+  c = e;
+  d = c;
+  d = a[c] + d;
+  return d;
+}
--
2.39.3