diff mbox series

tree-optimization/118405 - ICE with vector(1) T vs T load

Message ID 20250113123904.1E0C8385841F@sourceware.org
State Committed
Commit 31c3c1a83fd885b4687c9f6f7acd68af76d758d3
Headers
Series tree-optimization/118405 - ICE with vector(1) T vs T load |

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Commit Message

Richard Biener Jan. 13, 2025, 12:38 p.m. UTC 
  When vectorizing a load we are now checking alignment before emitting
a vector(1) T load instead of blindly assuming it's OK when we had
a scalar T load.  For reasons we're not handling alignment computation
optimally here but we shouldn't ICE when we fall back to loads of T.

The following ensures the IL remains correct by emitting VIEW_CONVERT
from T to vector(1) T when needed.  It also removes an earlier fix
done in r9-382-gbb4e47476537f6 for the same issue with VMAT_ELEMENTWISE.

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

	PR tree-optimization/118405
	* tree-vect-stmts.cc (vectorizable_load): When we fall back
	to scalar loads make sure we properly convert to vector(1) T
	when there was only a single vector element.
---
 gcc/tree-vect-stmts.cc | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index f5b3608f6b1..0c0f999d3e3 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -10731,9 +10731,6 @@  vectorizable_load (vec_info *vinfo,
 	  /* Else fall back to the default element-wise access.  */
 	  ltype = build_aligned_type (ltype, TYPE_ALIGN (TREE_TYPE (vectype)));
 	}
-      /* Load vector(1) scalar_type if it's 1 element-wise vectype.  */
-      else if (nloads == 1)
-	ltype = vectype;
 
       if (slp)
 	{
@@ -10782,11 +10779,11 @@  vectorizable_load (vec_info *vinfo,
 					     group_el * elsz + cst_offset);
 	      tree data_ref = build2 (MEM_REF, ltype, running_off, this_off);
 	      vect_copy_ref_info (data_ref, DR_REF (first_dr_info->dr));
-	      new_stmt = gimple_build_assign (make_ssa_name (ltype), data_ref);
+	      new_temp = make_ssa_name (ltype);
+	      new_stmt = gimple_build_assign (new_temp, data_ref);
 	      vect_finish_stmt_generation (vinfo, stmt_info, new_stmt, gsi);
 	      if (nloads > 1)
-		CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
-					gimple_assign_lhs (new_stmt));
+		CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, new_temp);
 
 	      group_el += lnel;
 	      if (! slp
@@ -10833,6 +10830,15 @@  vectorizable_load (vec_info *vinfo,
 		    }
 		}
 	    }
+	  else if (!costing_p && ltype != vectype)
+	    {
+	      new_stmt = gimple_build_assign (make_ssa_name (vectype),
+					      VIEW_CONVERT_EXPR,
+					      build1 (VIEW_CONVERT_EXPR,
+						      vectype, new_temp));
+	      vect_finish_stmt_generation (vinfo, stmt_info, new_stmt,
+					   gsi);
+	    }
 
 	  if (!costing_p)
 	    {