[gcc r14-5445] Loop distribution fix for SCC detection

[gcc r14-5445] Loop distribution fix for SCC detection

[Richard Biener]

https://gcc.gnu.org/g:bc390ae72ff974d6985639b5b392f6e9192c2ee7

commit r14-5445-gbc390ae72ff974d6985639b5b392f6e9192c2ee7
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Nov 14 12:53:18 2023 +0100

    Loop distribution fix for SCC detection
    
    The following adjusts data_dep_in_cycle_p to properly consider the
    whole loop nest when looking for data dep cycles and exempting
    zero-distance DDRs instead of just the outermost loop.
    
            * tree-loop-distribution.cc (loop_distribution::data_dep_in_cycle_p):
            Consider all loops in the nest when looking for
            lambda_vector_zerop.

Diff:
---
 gcc/tree-loop-distribution.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/tree-loop-distribution.cc b/gcc/tree-loop-distribution.cc
index 8e92af61c57..5ededd97c3d 100644
--- a/gcc/tree-loop-distribution.cc
+++ b/gcc/tree-loop-distribution.cc
@@ -1440,7 +1440,7 @@ loop_distribution::data_dep_in_cycle_p (struct graph *rdg,
   else if (DDR_NUM_DIST_VECTS (ddr) > 1)
     return true;
   else if (DDR_REVERSED_P (ddr)
-	   || lambda_vector_zerop (DDR_DIST_VECT (ddr, 0), 1))
+	   || lambda_vector_zerop (DDR_DIST_VECT (ddr, 0), DDR_NB_LOOPS (ddr)))
     return false;
 
   return true;