[Joern Rennecke]

At the moment, for a match_dup in a define_cond_exec, you'd have to
give the number in the
resulting pattern(s) rather than in the substitute pattern.  That's
not only wrong, but can also
be impossible when the pattern should apply to multiple patterns with
different operand numbers.

The attached patch fixes this.

Bootstrapped on x86_64-pc-linux-gnu.

2020-12-12  Joern Rennecke  <joern.renne...@embecosm.com>

        Fix match_dup bug of define_cond_exec.
        * gensupport.c (alter_predicate_for_insn): Handle MATCH_DUP.

diff --git a/gcc/gensupport.c b/gcc/gensupport.c
index e1ca06dbc1e..92275358078 100644
--- a/gcc/gensupport.c
+++ b/gcc/gensupport.c
@@ -1230,6 +1230,7 @@ alter_predicate_for_insn (rtx pattern, int alt, int 
max_op,
     case MATCH_OPERATOR:
     case MATCH_SCRATCH:
     case MATCH_PARALLEL:
+    case MATCH_DUP:
       XINT (pattern, 0) += max_op;
       break;