use local info about maxBits and sign-extendedness in OptimizeInstructions

fix the maxBits of a signed load, which this uncovered - all the bits may be used in such a case

4 files changed, 548 insertions, 10 deletions

diff --git a/test/emcc_hello_world.fromasm b/test/emcc_hello_world.fromasm
index 88db1c1ce..f01ba2f5d 100644
--- a/test/emcc_hello_world.fromasm
+++ b/test/emcc_hello_world.fromasm
@@ -5507,10 +5507,7 @@
                                                               (tee_local $5
                                                                 (i32.add
                                                                   (i32.xor
-                                                                    (i32.and
-                                                                      (get_local $32)
-                                                                      (i32.const 1)
-                                                                    )
+                                                                    (get_local $32)
                                                                     (i32.const 1)
                                                                   )
                                                                   (get_local $17)
diff --git a/test/emcc_hello_world.fromasm.imprecise b/test/emcc_hello_world.fromasm.imprecise
index 5ed229e6f..22878e91f 100644
--- a/test/emcc_hello_world.fromasm.imprecise
+++ b/test/emcc_hello_world.fromasm.imprecise
@@ -5444,10 +5444,7 @@
                                                               (tee_local $5
                                                                 (i32.add
                                                                   (i32.xor
-                                                                    (i32.and
-                                                                      (get_local $32)
-                                                                      (i32.const 1)
-                                                                    )
+                                                                    (get_local $32)
                                                                     (i32.const 1)
                                                                   )
                                                                   (get_local $17)
diff --git a/test/passes/optimize-instructions.txt b/test/passes/optimize-instructions.txt
index 31dceaf60..80d264e94 100644
--- a/test/passes/optimize-instructions.txt
+++ b/test/passes/optimize-instructions.txt
@@ -1240,8 +1240,22 @@
       )
     )
     (drop
+      (i32.shr_s
+        (i32.shl
+          (i32.shr_u
+            (i32.load8_s
+              (i32.const 256)
+            )
+            (i32.const 1)
+          )
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
       (i32.shr_u
-        (i32.load8_s
+        (i32.load8_u
           (i32.const 256)
         )
         (i32.const 1)
@@ -1344,4 +1358,247 @@
       )
     )
   )
+  (func $local-info-zero-ext (type $4) (param $0 i32) (param $1 i32)
+    (local $x i32)
+    (local $y i32)
+    (local $z i32)
+    (local $w i32)
+    (set_local $x
+      (i32.const 212)
+    )
+    (drop
+      (get_local $x)
+    )
+    (set_local $y
+      (i32.const 500)
+    )
+    (drop
+      (i32.and
+        (get_local $y)
+        (i32.const 255)
+      )
+    )
+    (set_local $0
+      (i32.const 212)
+    )
+    (drop
+      (i32.and
+        (get_local $0)
+        (i32.const 255)
+      )
+    )
+    (set_local $z
+      (i32.const 212)
+    )
+    (set_local $z
+      (i32.const 220)
+    )
+    (drop
+      (get_local $z)
+    )
+    (set_local $w
+      (i32.const 212)
+    )
+    (set_local $w
+      (i32.const 1000)
+    )
+    (drop
+      (i32.and
+        (get_local $w)
+        (i32.const 255)
+      )
+    )
+  )
+  (func $local-info-sign-ext-bitsize (type $4) (param $0 i32) (param $1 i32)
+    (local $x i32)
+    (local $y i32)
+    (local $z i32)
+    (local $w i32)
+    (set_local $x
+      (i32.const 127)
+    )
+    (drop
+      (get_local $x)
+    )
+    (set_local $y
+      (i32.const 128)
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $y)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $0
+      (i32.const 127)
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $z
+      (i32.const 127)
+    )
+    (set_local $z
+      (i32.const 100)
+    )
+    (drop
+      (get_local $z)
+    )
+    (set_local $w
+      (i32.const 127)
+    )
+    (set_local $w
+      (i32.const 150)
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $w)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+  )
+  (func $local-info-sign-ext-already-exted (type $4) (param $0 i32) (param $1 i32)
+    (local $x i32)
+    (local $y i32)
+    (local $z i32)
+    (local $w i32)
+    (set_local $x
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (get_local $x)
+    )
+    (set_local $y
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 16)
+        )
+        (i32.const 16)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $y)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $0
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $z
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $z
+      (i32.shr_s
+        (i32.shl
+          (get_local $1)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (get_local $z)
+    )
+    (set_local $w
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $w
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 23)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $w)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 23)
+      )
+    )
+  )
+  (func $signed-loads-fill-the-bits (type $3) (param $$e i32) (result i32)
+    (local $$0 i32)
+    (local $$conv i32)
+    (set_local $$0
+      (i32.load8_s
+        (i32.const 1024)
+      )
+    )
+    (set_local $$conv
+      (i32.and
+        (get_local $$0)
+        (i32.const 255)
+      )
+    )
+    (return
+      (i32.eq
+        (get_local $$conv)
+        (get_local $$e)
+      )
+    )
+  )
 )
diff --git a/test/passes/optimize-instructions.wast b/test/passes/optimize-instructions.wast
index c305ccbbb..0169bb054 100644
--- a/test/passes/optimize-instructions.wast
+++ b/test/passes/optimize-instructions.wast
@@ -1556,7 +1556,21 @@
       (i32.shr_s
         (i32.shl
           (i32.shr_u
-            (i32.load8_s ;; one byte, but reduced to 7
+            (i32.load8_s ;; one byte, but sexted to 32
+              (i32.const 256)
+            )
+            (i32.const 1)
+          )
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (i32.shr_u
+            (i32.load8_u ;; one byte, but reduced to 7
               (i32.const 256)
             )
             (i32.const 1)
@@ -1691,4 +1705,277 @@
       )
     )
   )
+  (func $local-info-zero-ext (param $0 i32) (param $1 i32)
+    (local $x i32)
+    (local $y i32)
+    (local $z i32)
+    (local $w i32)
+    (set_local $x
+      (i32.const 212) ;; mask is unneeded, we are small
+    )
+    (drop
+      (i32.and
+        (get_local $x)
+        (i32.const 255)
+      )
+    )
+    (set_local $y
+      (i32.const 500) ;; mask is needed, we are too big
+    )
+    (drop
+      (i32.and
+        (get_local $y)
+        (i32.const 255)
+      )
+    )
+    (set_local $0
+      (i32.const 212) ;; mask is unneeded, but we are a param, not a var, so no
+    )
+    (drop
+      (i32.and
+        (get_local $0)
+        (i32.const 255)
+      )
+    )
+    (set_local $z
+      (i32.const 212) ;; mask is unneeded, we are small
+    )
+    (set_local $z
+      (i32.const 220) ;; mask is still unneeded even with 2 uses
+    )
+    (drop
+      (i32.and
+        (get_local $z)
+        (i32.const 255)
+      )
+    )
+    (set_local $w
+      (i32.const 212) ;; mask is unneeded, we are small
+    )
+    (set_local $w
+      (i32.const 1000) ;; mask is needed, one use is too big
+    )
+    (drop
+      (i32.and
+        (get_local $w)
+        (i32.const 255)
+      )
+    )
+  )
+  (func $local-info-sign-ext-bitsize (param $0 i32) (param $1 i32)
+    (local $x i32)
+    (local $y i32)
+    (local $z i32)
+    (local $w i32)
+    (set_local $x
+      (i32.const 127) ;; mask is unneeded, we are small
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $x)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $y
+      (i32.const 128) ;; mask is needed, we are too big
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $y)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $0
+      (i32.const 127) ;; mask is unneeded, but we are a param, not a var, so no
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $z
+      (i32.const 127) ;; mask is unneeded, we are small
+    )
+    (set_local $z
+      (i32.const 100) ;; mask is still unneeded even with 2 uses
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $z)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $w
+      (i32.const 127) ;; mask is unneeded, we are small
+    )
+    (set_local $w
+      (i32.const 150) ;; mask is needed, one use is too big
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $w)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+  )
+  (func $local-info-sign-ext-already-exted (param $0 i32) (param $1 i32)
+    (local $x i32)
+    (local $y i32)
+    (local $z i32)
+    (local $w i32)
+    (set_local $x
+      (i32.shr_s
+        (i32.shl
+          (get_local $0) ;; already sign-exted here, so no need later
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $x)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $y
+      (i32.shr_s
+        (i32.shl
+          (get_local $0) ;; already sign-exted here, but wrong bit size
+          (i32.const 16)
+        )
+        (i32.const 16)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $y)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $0
+      (i32.shr_s
+        (i32.shl
+          (get_local $0) ;; already sign-exted here, so no need later, but we are a param
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $0)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $z
+      (i32.shr_s
+        (i32.shl
+          (get_local $0) ;; already sign-exted here, so no need later
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $z
+      (i32.shr_s
+        (i32.shl
+          (get_local $1) ;; already sign-exted here, so no need later
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $z)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $w
+      (i32.shr_s
+        (i32.shl
+          (get_local $0) ;; already sign-exted here, so no need later
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (set_local $w
+      (i32.shr_s
+        (i32.shl
+          (get_local $0) ;; not quite a sign-ext
+          (i32.const 23)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop
+      (i32.shr_s
+        (i32.shl
+          (get_local $w)
+          (i32.const 24)
+        )
+        (i32.const 24)
+      )
+    )
+    (drop ;; odd corner case
+      (i32.shr_s
+        (i32.shl
+          (get_local $0) ;; param, so we should know nothing
+          (i32.const 24)
+        )
+        (i32.const 23) ;; different shift, smaller
+      )
+    )
+  )
+  (func $signed-loads-fill-the-bits (param $$e i32) (result i32)
+    (local $$0 i32)
+    (local $$conv i32)
+    (set_local $$0
+      (i32.load8_s ;; one byte, but 32 bits due to sign-extend
+        (i32.const 1024)
+      )
+    )
+    (set_local $$conv
+      (i32.and
+        (get_local $$0)
+        (i32.const 255) ;; so we need this zexting!
+      )
+    )
+    (return
+      (i32.eq
+        (get_local $$conv)
+        (get_local $$e)
+      )
+    )
+  )
 )