Improve precompute-propagate (#1514)

Propagate constants through a tee_local. Found by Souper. Details in patch comments - basically we didn't differentiate precomputing a value and an expression.

2 files changed, 51 insertions, 0 deletions

diff --git a/test/passes/precompute-propagate.txt b/test/passes/precompute-propagate.txt
index 262b4880c..15abe1f2e 100644
--- a/test/passes/precompute-propagate.txt
+++ b/test/passes/precompute-propagate.txt
@@ -1,6 +1,7 @@
 (module
  (type $0 (func (param i32)))
  (type $1 (func (param i32) (result i32)))
+ (type $2 (func (param i32 i32) (result i32)))
  (func $basic (; 0 ;) (type $0) (param $p i32)
   (local $x i32)
   (set_local $x
@@ -210,4 +211,26 @@
    (br $loop)
   )
  )
+ (func $through-tee (; 13 ;) (type $2) (param $x i32) (param $y i32) (result i32)
+  (set_local $x
+   (tee_local $y
+    (i32.const 7)
+   )
+  )
+  (return
+   (i32.const 14)
+  )
+ )
+ (func $through-tee-more (; 14 ;) (type $2) (param $x i32) (param $y i32) (result i32)
+  (set_local $x
+   (i32.eqz
+    (tee_local $y
+     (i32.const 7)
+    )
+   )
+  )
+  (return
+   (i32.const 7)
+  )
+ )
 )
diff --git a/test/passes/precompute-propagate.wast b/test/passes/precompute-propagate.wast
index af1a21ba2..4cf440829 100644
--- a/test/passes/precompute-propagate.wast
+++ b/test/passes/precompute-propagate.wast
@@ -109,5 +109,33 @@
       (br $loop)
     )
   )
+  (func $through-tee (param $x i32) (param $y i32) (result i32)
+    (set_local $x
+      (tee_local $y
+        (i32.const 7)
+      )
+    )
+    (return
+      (i32.add
+        (get_local $x)
+        (get_local $y)
+      )
+    )
+  )
+  (func $through-tee-more (param $x i32) (param $y i32) (result i32)
+    (set_local $x
+      (i32.eqz
+        (tee_local $y
+          (i32.const 7)
+        )
+      )
+    )
+    (return
+      (i32.add
+        (get_local $x)
+        (get_local $y)
+      )
+    )
+  )
 )