target/104762 - vectorization costs of CONSTRUCTORs

[gcc.git] / gcc / config / i386 / i386.cc

diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 4121f98622117ece739068e39d2738e36c3f5379..23bedea92bd33eaf0438407ff3abb8566cb3f835 100644 (file)
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -22597,16 +22597,21 @@ ix86_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 
       case vec_construct:
        {
-         /* N element inserts into SSE vectors.  */
-         int cost = TYPE_VECTOR_SUBPARTS (vectype) * ix86_cost->sse_op;
+         int n = TYPE_VECTOR_SUBPARTS (vectype);
+         /* N - 1 element inserts into an SSE vector, the possible
+            GPR -> XMM move is accounted for in add_stmt_cost.  */
+         if (GET_MODE_BITSIZE (mode) <= 128)
+           return (n - 1) * ix86_cost->sse_op;
          /* One vinserti128 for combining two SSE vectors for AVX256.  */
-         if (GET_MODE_BITSIZE (mode) == 256)
-           cost += ix86_vec_cost (mode, ix86_cost->addss);
+         else if (GET_MODE_BITSIZE (mode) == 256)
+           return ((n - 2) * ix86_cost->sse_op
+                   + ix86_vec_cost (mode, ix86_cost->addss));
          /* One vinserti64x4 and two vinserti128 for combining SSE
             and AVX256 vectors to AVX512.  */
          else if (GET_MODE_BITSIZE (mode) == 512)
-           cost += 3 * ix86_vec_cost (mode, ix86_cost->addss);
-         return cost;
+           return ((n - 4) * ix86_cost->sse_op
+                   + 3 * ix86_vec_cost (mode, ix86_cost->addss));
+         gcc_unreachable ();
        }
 
       default: