Remove redundant sign/zero extension for SIMD broadcasts

dotnet · Oct 13, 2024 · 01735f3 · 01735f3
1 parent 4900696
commit 01735f3
Showing 1 changed file with 16 additions and 0 deletions.
diff --git a/src/coreclr/jit/lowerxarch.cpp b/src/coreclr/jit/lowerxarch.cpp
@@ -10356,6 +10356,22 @@ void Lowering::ContainCheckHWIntrinsic(GenTreeHWIntrinsic* node)
 
                                 op1 = node->Op(1);
                                 op1->ClearContained();
+
+                                // Drop GT_CAST if it doesn't change the op1's bits we're about to broadcast
+                                if (op1->OperIs(GT_CAST) && !op1->gtOverflow())
+                                {
+                                    GenTreeCast* cast = op1->AsCast();
+                                    if (!varTypeIsFloating(cast->CastToType()) &&
+                                        !varTypeIsFloating(cast->CastFromType()) &&
+                                        (genTypeSize(cast->CastToType()) >= genTypeSize(simdBaseType)) &&
+                                        (genTypeSize(cast->CastFromType()) >= genTypeSize(simdBaseType)))
+                                    {
+                                        BlockRange().Remove(op1);
+                                        op1 = cast->CastOp();
+                                        op1->ClearContained();
+                                        node->Op(1) = op1;
+                                    }
+                                }
                             }
                         }
                         break;