Optimize bulk memory.copy (#3038)

Replace it with a load and a store when the size is a small constant and remove it entirely when it would be a nop.

2 files changed, 140 insertions, 0 deletions

diff --git a/test/passes/optimize-instructions_all-features.txt b/test/passes/optimize-instructions_all-features.txt
index e08702b91..b97106f2d 100644
--- a/test/passes/optimize-instructions_all-features.txt
+++ b/test/passes/optimize-instructions_all-features.txt
@@ -10,6 +10,7 @@
  (type $i64_=>_i64 (func (param i64) (result i64)))
  (type $i32_i64_f32_=>_none (func (param i32 i64 f32)))
  (type $i32_i64_f32_f64_=>_none (func (param i32 i64 f32 f64)))
+ (type $i32_i32_i32_=>_none (func (param i32 i32 i32)))
  (type $i32_i32_f64_f64_=>_none (func (param i32 i32 f64 f64)))
  (type $i32_i64_f64_i32_=>_none (func (param i32 i64 f64 i32)))
  (type $none_=>_f64 (func (result f64)))
@@ -3727,6 +3728,72 @@
    )
   )
  )
+ (func $optimize-bulk-memory-copy (param $dst i32) (param $src i32) (param $sz i32)
+  (nop)
+  (block
+   (drop
+    (local.get $dst)
+   )
+   (drop
+    (local.get $src)
+   )
+  )
+  (i32.store8
+   (local.get $dst)
+   (i32.load8_u
+    (local.get $src)
+   )
+  )
+  (i32.store16 align=1
+   (local.get $dst)
+   (i32.load16_u align=1
+    (local.get $src)
+   )
+  )
+  (memory.copy
+   (local.get $dst)
+   (local.get $src)
+   (i32.const 3)
+  )
+  (i32.store align=1
+   (local.get $dst)
+   (i32.load align=1
+    (local.get $src)
+   )
+  )
+  (memory.copy
+   (local.get $dst)
+   (local.get $src)
+   (i32.const 5)
+  )
+  (memory.copy
+   (local.get $dst)
+   (local.get $src)
+   (i32.const 6)
+  )
+  (memory.copy
+   (local.get $dst)
+   (local.get $src)
+   (i32.const 7)
+  )
+  (i64.store align=1
+   (local.get $dst)
+   (i64.load align=1
+    (local.get $src)
+   )
+  )
+  (v128.store align=1
+   (local.get $dst)
+   (v128.load align=1
+    (local.get $src)
+   )
+  )
+  (memory.copy
+   (local.get $dst)
+   (local.get $src)
+   (local.get $sz)
+  )
+ )
 )
 (module
  (type $none_=>_none (func))
diff --git a/test/passes/optimize-instructions_all-features.wast b/test/passes/optimize-instructions_all-features.wast
index 2790cc9ea..b62ecdcfd 100644
--- a/test/passes/optimize-instructions_all-features.wast
+++ b/test/passes/optimize-instructions_all-features.wast
@@ -4233,6 +4233,79 @@
       )
     ))
   )
+  (func $optimize-bulk-memory-copy (param $dst i32) (param $src i32) (param $sz i32)
+    (memory.copy  ;; nop
+      (local.get $dst)
+      (local.get $dst)
+      (local.get $sz)
+    )
+
+    (memory.copy  ;; nop
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 0)
+    )
+
+    (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 1)
+    )
+
+    (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 2)
+    )
+
+    (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 3)
+    )
+
+    (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 4)
+    )
+
+    (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 5)
+    )
+
+    (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 6)
+    )
+
+    (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 7)
+    )
+
+    (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 8)
+    )
+
+     (memory.copy
+      (local.get $dst)
+      (local.get $src)
+      (i32.const 16)
+    )
+
+    (memory.copy  ;; skip
+      (local.get $dst)
+      (local.get $src)
+      (local.get $sz)
+    )
+  )
 )
 (module
   (import "env" "memory" (memory $0 (shared 256 256)))