fix off-by-one in assertion in optimize-instructions

Author: kripken

src/passes/OptimizeInstructions.cpp

@@ -453,7 +453,7 @@ struct OptimizeInstructions : public WalkerPass<PostWalker<OptimizeInstructions,
             if ((count > 0 && count < 32 - bits) || (constSignBit && count == 0)) {
               // mixed or [zero upper const bits with sign bit set]; the compared values can never be identical, so
               // force something definitely impossible even after zext
-              assert(bits < 31);
+              assert(bits < 32);
               c->value = Literal(int32_t(0x80000000));
               // TODO: if no side effects, we can just replace it all with 1 or 0
             } else {

test/passes/optimize-instructions.txt

@@ -1993,4 +1993,17 @@
    )
   )
  )
+ (func $sign-ext-1-and-ne (type $2) (result i32)
+  (select
+   (i32.ne
+    (i32.and
+     (call $sign-ext-1-and-ne)
+     (i32.const 2147483647)
+    )
+    (i32.const -2147483648)
+   )
+   (i32.const 2)
+   (i32.const 1)
+  )
+ )
 )

test/passes/optimize-instructions.wast

@@ -2417,4 +2417,20 @@
     )
    )
   )
+  (func $sign-ext-1-and-ne (result i32)
+   (select
+    (i32.ne
+     (i32.const 1333788672)
+     (i32.shr_s
+      (i32.shl
+       (call $sign-ext-1-and-ne)
+       (i32.const 1)
+      )
+      (i32.const 1)
+     )
+    )
+    (i32.const 2)
+    (i32.const 1)
+   )
+  )
 )