Partially fix Precompute on SIMD (#3983)

We had the logic in only one place.

3 files changed, 24 insertions, 10 deletions

diff --git a/src/passes/Precompute.cpp b/src/passes/Precompute.cpp
index a832c9e85..fa6e8e9ed 100644
--- a/src/passes/Precompute.cpp
+++ b/src/passes/Precompute.cpp
@@ -172,17 +172,8 @@ struct Precompute
     if (Properties::isConstantExpression(curr) || curr->is<Nop>()) {
       return;
     }
-    // Until engines implement v128.const and we have SIMD-aware optimizations
-    // that can break large v128.const instructions into smaller consts and
-    // splats, do not try to precompute v128 expressions.
-    if (curr->type.isVector()) {
-      return;
-    }
     // try to evaluate this into a const
     Flow flow = precomputeExpression(curr);
-    if (flow.getType().hasVector()) {
-      return;
-    }
     if (!canEmitConstantFor(flow.values)) {
       return;
     }
@@ -236,6 +227,12 @@ private:
   // Precompute an expression, returning a flow, which may be a constant
   // (that we can replace the expression with if replaceExpression is set).
   Flow precomputeExpression(Expression* curr, bool replaceExpression = true) {
+    // Until engines implement v128.const and we have SIMD-aware optimizations
+    // that can break large v128.const instructions into smaller consts and
+    // splats, do not try to precompute v128 expressions.
+    if (curr->type.isVector()) {
+      return Flow(NONCONSTANT_FLOW);
+    }
     Flow flow;
     try {
       flow =
@@ -250,6 +247,9 @@ private:
         !canEmitConstantFor(flow.values)) {
       return Flow(NONCONSTANT_FLOW);
     }
+    if (flow.getType().hasVector()) {
+      return Flow(NONCONSTANT_FLOW);
+    }
     return flow;
   }
 
diff --git a/test/passes/precompute_all-features.txt b/test/passes/precompute_all-features.txt
index b707f4248..dc93f90e4 100644
--- a/test/passes/precompute_all-features.txt
+++ b/test/passes/precompute_all-features.txt
@@ -1,8 +1,8 @@
 (module
  (type $none_=>_none (func))
  (type $none_=>_i32 (func (result i32)))
- (type $none_=>_f64 (func (result f64)))
  (type $none_=>_v128 (func (result v128)))
+ (type $none_=>_f64 (func (result f64)))
  (type $0 (func (param i32)))
  (type $none_=>_i32_i64 (func (result i32 i64)))
  (type $none_=>_externref (func (result externref)))
@@ -222,6 +222,13 @@
    (i32.const 0)
   )
  )
+ (func $no-simd-precompute_2 (result v128)
+  (i32x4.extadd_pairwise_i16x8_s
+   (i32x4.splat
+    (i32.const 0)
+   )
+  )
+ )
  (func $no-simd-precompute-if (result v128)
   (return
    (i32x4.splat
diff --git a/test/passes/precompute_all-features.wast b/test/passes/precompute_all-features.wast
index 1275524e0..e306be495 100644
--- a/test/passes/precompute_all-features.wast
+++ b/test/passes/precompute_all-features.wast
@@ -329,6 +329,13 @@
     (i32.const 0)
    )
   )
+  (func $no-simd-precompute_2 (result v128)
+   (i32x4.extadd_pairwise_i16x8_s
+    (i32x4.splat
+     (i32.const 0)
+    )
+   )
+  )
   (func $no-simd-precompute-if (result v128)
    (return
     (i32x4.splat