Some refactorings in addition to #3338 (#3336)

See discussion in #3303

3 files changed, 114 insertions, 16 deletions

diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index 83bee9a0f..019d6bda1 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -1936,31 +1936,27 @@ private:
           }
         }
       }
-      // signed(x - y) <=> 0  =>  x <=> y
-      //
+      // x - y == 0  =>  x == y
+      // x - y != 0  =>  x != y
       // unsigned(x - y) > 0    =>   x != y
       // unsigned(x - y) <= 0   =>   x == y
       {
+        using namespace Abstract;
         using namespace Match;
 
-        BinaryOp op;
         Binary* inner;
         // unsigned(x - y) > 0    =>   x != y
         if (matches(curr,
-                    binary(Abstract::GtU,
-                           binary(&inner, Abstract::Sub, any(), any()),
-                           ival(0)))) {
-          curr->op = Abstract::getBinary(type, Abstract::Ne);
+                    binary(GtU, binary(&inner, Sub, any(), any()), ival(0)))) {
+          curr->op = Abstract::getBinary(type, Ne);
           curr->right = inner->right;
           curr->left = inner->left;
           return curr;
         }
         // unsigned(x - y) <= 0   =>   x == y
         if (matches(curr,
-                    binary(Abstract::LeU,
-                           binary(&inner, Abstract::Sub, any(), any()),
-                           ival(0)))) {
-          curr->op = Abstract::getBinary(type, Abstract::Eq);
+                    binary(LeU, binary(&inner, Sub, any(), any()), ival(0)))) {
+          curr->op = Abstract::getBinary(type, Eq);
           curr->right = inner->right;
           curr->left = inner->left;
           return curr;
@@ -1970,11 +1966,9 @@ private:
         // This is not true for signed comparisons like x -y < 0 due to overflow
         // effects (e.g. 8 - 0x80000000 < 0 is not the same as 8 < 0x80000000).
         if (matches(curr,
-                    binary(&op,
-                           binary(&inner, Abstract::Sub, any(), any()),
-                           ival(0))) &&
-            (op == Abstract::getBinary(type, Abstract::Eq) ||
-             op == Abstract::getBinary(type, Abstract::Ne))) {
+                    binary(Eq, binary(&inner, Sub, any(), any()), ival(0))) ||
+            matches(curr,
+                    binary(Ne, binary(&inner, Sub, any(), any()), ival(0)))) {
           curr->right = inner->right;
           curr->left = inner->left;
           return curr;
diff --git a/test/passes/optimize-instructions_all-features.txt b/test/passes/optimize-instructions_all-features.txt
index 7d223020f..2cf034c7a 100644
--- a/test/passes/optimize-instructions_all-features.txt
+++ b/test/passes/optimize-instructions_all-features.txt
@@ -4842,6 +4842,58 @@
     (local.get $y)
    )
   )
+  (drop
+   (i32.eq
+    (local.get $x)
+    (i32.const -2147483648)
+   )
+  )
+  (drop
+   (i32.ne
+    (local.get $x)
+    (i32.const -2147483648)
+   )
+  )
+  (drop
+   (i32.lt_s
+    (i32.sub
+     (local.get $x)
+     (i32.const -2147483648)
+    )
+    (i32.const 0)
+   )
+  )
+  (drop
+   (i32.ge_s
+    (i32.sub
+     (local.get $x)
+     (i32.const -2147483648)
+    )
+    (i32.const 0)
+   )
+  )
+  (drop
+   (i32.gt_s
+    (i32.sub
+     (local.get $x)
+     (block $block (result i32)
+      (i32.const -2147483648)
+     )
+    )
+    (i32.const 0)
+   )
+  )
+  (drop
+   (i32.gt_s
+    (i32.sub
+     (local.get $x)
+     (block $block30 (result i32)
+      (i32.const -2147483648)
+     )
+    )
+    (i32.const 0)
+   )
+  )
  )
  (func $unsigned-context (param $x i32) (param $y i64)
   (drop
diff --git a/test/passes/optimize-instructions_all-features.wast b/test/passes/optimize-instructions_all-features.wast
index 5804c1b2a..24e8a9d61 100644
--- a/test/passes/optimize-instructions_all-features.wast
+++ b/test/passes/optimize-instructions_all-features.wast
@@ -5360,6 +5360,58 @@
       )
       (i32.const 0)
     ))
+    ;; i32(x - 0x80000000) == 0  ->  x == 0x80000000
+    (drop (i32.eq
+      (i32.sub
+        (local.get $x)
+        (i32.const 0x80000000)
+      )
+      (i32.const 0)
+    ))
+    ;; i32(x - 0x80000000) != 0  ->  x == 0x80000000
+    (drop (i32.ne
+      (i32.sub
+        (local.get $x)
+        (i32.const 0x80000000)
+      )
+      (i32.const 0)
+    ))
+    ;; i32(x - { 0x80000000 }) < 0  ->  skip
+    (drop (i32.lt_s
+      (i32.sub
+        (local.get $x)
+        (i32.const 0x80000000)
+      )
+      (i32.const 0)
+    ))
+    ;; i32(x - { 0x80000000 }) >= 0  ->  skip
+    (drop (i32.ge_s
+      (i32.sub
+        (local.get $x)
+        (i32.const 0x80000000)
+      )
+      (i32.const 0)
+    ))
+    ;; i32(x - { 0x80000000 }) > 0  ->  skip
+    (drop (i32.gt_s
+      (i32.sub
+        (local.get $x)
+        (block (result i32)
+          (i32.const 0x80000000)
+        )
+      )
+      (i32.const 0)
+    ))
+    ;; i32(x - { 0x80000000 }) <= 0  ->  skip
+    (drop (i32.gt_s
+      (i32.sub
+        (local.get $x)
+        (block (result i32)
+          (i32.const 0x80000000)
+        )
+      )
+      (i32.const 0)
+    ))
   )
   (func $unsigned-context (param $x i32) (param $y i64)
     (drop (i32.div_s