[PATCH] tree-optimization/103948 - detect vector vec_cmp in expand_vector_condition

[Uros Bizjak via Gcc-patches]

Currently, expand_vector_condition detects only vcondMN and vconduMN
named RTX patterns.  Teach it to also consider vec_cmpMN and vec_cmpuMN
RTX patterns when all ones vector is returned for true and all zeros vector
is returned for false.

Patch by Richard, I tested it on the patched x86 target and wrote a
ChangeLog entry.

(No testcase, it will be added in a follow-up target-dependent patch).

2022-01-10  Richard Biener  <rguent...@suse.de>

gcc/ChangeLog:

    PR tree-optimization/103948
    * tree-vect-generic.c (expand_vector_condition): Return true if
    all ones vector is returned for true, all zeros vector for false
    and the target defines corresponding vec_cmp{,u}MN named RTX pattern.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Pre-approved in the PR and pushed to master.

Uros.

diff --git a/gcc/tree-vect-generic.c b/gcc/tree-vect-generic.c
index 6afb6999cd7..5814a71a5bb 100644
--- a/gcc/tree-vect-generic.c
+++ b/gcc/tree-vect-generic.c
@@ -1052,7 +1052,9 @@ expand_vector_condition (gimple_stmt_iterator *gsi, 
bitmap dce_ssa_names)
        }
     }
 
-  if (expand_vec_cond_expr_p (type, TREE_TYPE (a1), code))
+  if (expand_vec_cond_expr_p (type, TREE_TYPE (a1), code)
+      || (integer_all_onesp (b) && integer_zerop (c)
+         && expand_vec_cmp_expr_p (type, TREE_TYPE (a1), code)))
     {
       gcc_assert (TREE_CODE (a) == SSA_NAME || TREE_CODE (a) == VECTOR_CST);
       return true;