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tree-optimization/113018 - ICE with BB reduction vectorization

Message ID 20231214155543.0B013138F2@imap2.dmz-prg2.suse.org
State Unresolved
Headers
Series tree-optimization/113018 - ICE with BB reduction vectorization |

Checks

Context Check Description
snail/gcc-patch-check warning Git am fail log

Commit Message

Richard Biener Dec. 14, 2023, 3:55 p.m. UTC 
  When BB reduction vectorization picks up a chain with an ASM def
in it and that's inside the vectorized region we fail to get its
LHS.  Instead of trying to get the correct def the following
avoids vectorizing such def and instead keeps it as def to add
in the epilog.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR tree-optimization/113018
	* tree-vect-slp.cc (vect_slp_check_for_roots): Only start
	SLP discovery from stmts with a LHS.
---
 gcc/tree-vect-slp.cc | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)
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Patch

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index f8a168caa60..a82fca45161 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -7419,7 +7419,12 @@  vect_slp_check_for_roots (bb_vec_info bb_vinfo)
 		      invalid = true;
 		      break;
 		    }
-		  if (chain[i].dt != vect_internal_def)
+		  if (chain[i].dt != vect_internal_def
+		      /* Avoid stmts where the def is not the LHS, like
+			 ASMs.  */
+		      || (gimple_get_lhs (bb_vinfo->lookup_def
+						      (chain[i].op)->stmt)
+			  != chain[i].op))
 		    remain_cnt++;
 		}
 	      if (!invalid && chain.length () - remain_cnt > 1)
@@ -7431,8 +7436,11 @@  vect_slp_check_for_roots (bb_vec_info bb_vinfo)
 		    remain.create (remain_cnt);
 		  for (unsigned i = 0; i < chain.length (); ++i)
 		    {
-		      if (chain[i].dt == vect_internal_def)
-			stmts.quick_push (bb_vinfo->lookup_def (chain[i].op));
+		      stmt_vec_info stmt_info;
+		      if (chain[i].dt == vect_internal_def
+			  && ((stmt_info = bb_vinfo->lookup_def (chain[i].op)),
+			      gimple_get_lhs (stmt_info->stmt) == chain[i].op))
+			stmts.quick_push (stmt_info);
 		      else
 			remain.quick_push (chain[i].op);
 		    }