Add optimization from x < 0 || x > POSITIVE_CONST to `x > POSITIVE_…

…CONST` with unsigned comparison Fixes WebAssembly#6685
i582 · Oct 11, 2024 · 623ad09 · 623ad09
1 parent a8aa660
commit 623ad09
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diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
@@ -395,6 +395,25 @@ struct OptimizeInstructions
           return replaceCurrent(un);
         }
       }
+      {
+        // x < 0 || x > POSITIVE_CONST   ==>   x > POSITIVE_CONST (unsigned
+        // comparison)
+        Binary* bin;
+        Expression *x_left, *x_right;
+        Const* y;
+        // TODO: check if x_left === x_right
+        if (matches(curr,
+                    binary(&bin,
+                           OrInt32,
+                           binary(LtSInt32, pure(&x_left), i32(0)),
+                           binary(GtSInt32, pure(&x_right), constant(&y)))) &&
+            y->type == Type::i32 && y->value.geti32() > 0) {
+          bin->op = GtUInt32;
+          bin->left = x_left;
+          bin->right = y;
+          return;
+        }
+      }
       {
         // x <<>> (C & (31 | 63))   ==>   x <<>> C'
         // x <<>> (y & (31 | 63))   ==>   x <<>> y
@@ -679,6 +698,14 @@ struct OptimizeInstructions
       if (auto* ret = optimizeAddedConstants(curr)) {
         return replaceCurrent(ret);
       }
+    } else if (curr->op == SubInt32 || curr->op == SubInt64 ||
+               curr->op == AddVecI8x16 || curr->op == AddVecI16x8 ||
+               curr->op == SubVecI8x16 || curr->op == SubVecI16x8 ||
+               curr->op == AddVecI32x4 || curr->op == AddVecI64x2 ||
+               curr->op == SubVecI32x4 || curr->op == SubVecI64x2) {
+      if (auto* ret = optimizeAddedConstants(curr)) {
+        return replaceCurrent(ret);
+      }
     } else if (curr->op == MulFloat32 || curr->op == MulFloat64 ||
                curr->op == DivFloat32 || curr->op == DivFloat64) {
       if (curr->left->type == curr->right->type) {

diff --git a/test/lit/passes/optimize-instructions-cmps.wast b/test/lit/passes/optimize-instructions-cmps.wast
@@ -0,0 +1,162 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py and should not be edited.
+;; RUN: wasm-opt %s --optimize-instructions -S -o - | filecheck %s
+
+;; Tests for "x < 0 || x > POSITIVE_CONST   ==>   x > POSITIVE_CONST (unsigned comparison)" optimization
+
+(module
+ ;; CHECK:      (global $g (mut i32) (i32.const 0))
+ (global $g (mut i32) (i32.const 0))
+
+ ;; CHECK:      (func $cmp (param $0 i32) (result i32)
+ ;; CHECK-NEXT:  (i32.gt_u
+ ;; CHECK-NEXT:   (local.get $0)
+ ;; CHECK-NEXT:   (i32.const 255)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $cmp (param $0 i32) (result i32)
+  (i32.or
+   (i32.lt_s
+    (local.get $0)
+    (i32.const 0)
+   )
+   (i32.gt_s
+    (local.get $0)
+    (i32.const 255)
+   )
+  )
+ )
+
+ ;; CHECK:      (func $cmp2 (param $0 i32) (result i32)
+ ;; CHECK-NEXT:  (i32.or
+ ;; CHECK-NEXT:   (i32.lt_s
+ ;; CHECK-NEXT:    (local.get $0)
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (i32.gt_s
+ ;; CHECK-NEXT:    (local.get $0)
+ ;; CHECK-NEXT:    (i32.const -255)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $cmp2 (param $0 i32) (result i32)
+  (i32.or
+   (i32.lt_s
+    (local.get $0)
+    (i32.const 0)
+   )
+   (i32.gt_s
+    (local.get $0)
+    (i32.const -255) ;; negative number
+   )
+  )
+ )
+
+ ;; CHECK:      (func $cmp3 (param $0 i32) (result i32)
+ ;; CHECK-NEXT:  (i32.or
+ ;; CHECK-NEXT:   (i32.lt_s
+ ;; CHECK-NEXT:    (local.get $0)
+ ;; CHECK-NEXT:    (i32.const 10)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (i32.gt_s
+ ;; CHECK-NEXT:    (local.get $0)
+ ;; CHECK-NEXT:    (i32.const 255)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $cmp3 (param $0 i32) (result i32)
+  (i32.or
+   (i32.lt_s
+    (local.get $0)
+    (i32.const 10) ;; note this
+   )
+   (i32.gt_s
+    (local.get $0)
+    (i32.const 255)
+   )
+  )
+ )
+
+ ;; CHECK:      (func $set_global_and_return (param $x i32) (result i32)
+ ;; CHECK-NEXT:  (global.set $g
+ ;; CHECK-NEXT:   (local.get $x)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (local.get $x)
+ ;; CHECK-NEXT: )
+ (func $set_global_and_return (param $x i32) (result i32)
+   (global.set $g (local.get $x)) ;; side-effect
+   (local.get $x)
+ )
+
+ ;; CHECK:      (func $cmp4 (result i32)
+ ;; CHECK-NEXT:  (i32.or
+ ;; CHECK-NEXT:   (i32.lt_s
+ ;; CHECK-NEXT:    (call $set_global_and_return
+ ;; CHECK-NEXT:     (i32.const 10)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (i32.gt_s
+ ;; CHECK-NEXT:    (call $set_global_and_return
+ ;; CHECK-NEXT:     (i32.const 10)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:    (i32.const 255)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $cmp4 (result i32)
+  (i32.or
+   (i32.lt_s
+    (call $set_global_and_return (i32.const 10)) ;; x with side-effect
+    (i32.const 0)
+   )
+   (i32.gt_s
+    (call $set_global_and_return (i32.const 10))
+    (i32.const 255)
+   )
+  )
+ )
+
+ ;; CHECK:      (func $cmp5 (param $0 i32) (param $1 i32) (result i32)
+ ;; CHECK-NEXT:  (i32.gt_u
+ ;; CHECK-NEXT:   (local.get $0)
+ ;; CHECK-NEXT:   (i32.const 255)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $cmp5 (param $0 i32) (param $1 i32) (result i32)
+  (i32.or
+   (i32.lt_s
+    (local.get $0)
+    (i32.const 0)
+   )
+   (i32.gt_s
+    (local.get $1) ;; note this
+    (i32.const 255)
+   )
+  )
+ )
+
+ ;; CHECK:      (func $cmp6 (param $0 i32) (param $1 i32) (result i32)
+ ;; CHECK-NEXT:  (i32.or
+ ;; CHECK-NEXT:   (i32.lt_s
+ ;; CHECK-NEXT:    (local.get $0)
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (i32.gt_s
+ ;; CHECK-NEXT:    (local.get $0)
+ ;; CHECK-NEXT:    (local.get $1)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $cmp6 (param $0 i32) (param $1 i32) (result i32)
+  (i32.or
+   (i32.lt_s
+    (local.get $0)
+    (i32.const 0)
+   )
+   (i32.gt_s
+    (local.get $0)
+    (local.get $1) ;; non-constant
+   )
+  )
+ )
+)