GUFA: Propagate string literals (#6262)

We only noted the type but not the literal value.

2 files changed, 61 insertions, 1 deletions

diff --git a/src/ir/possible-contents.cpp b/src/ir/possible-contents.cpp
index 2f900f0ed..8d6891017 100644
--- a/src/ir/possible-contents.cpp
+++ b/src/ir/possible-contents.cpp
@@ -1065,7 +1065,8 @@ struct InfoCollector
     addRoot(curr, PossibleContents::exactType(curr->type));
   }
   void visitStringConst(StringConst* curr) {
-    addRoot(curr, PossibleContents::exactType(curr->type));
+    addRoot(curr,
+            PossibleContents::literal(Literal(std::string(curr->string.str))));
   }
   void visitStringMeasure(StringMeasure* curr) {
     // TODO: optimize when possible
diff --git a/test/lit/passes/gufa-strings.wast b/test/lit/passes/gufa-strings.wast
new file mode 100644
index 000000000..0501e3f56
--- /dev/null
+++ b/test/lit/passes/gufa-strings.wast
@@ -0,0 +1,59 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+;; RUN: foreach %s %t wasm-opt -all --gufa -S -o - | filecheck %s
+
+(module
+  ;; CHECK:      (type $0 (func))
+
+  ;; CHECK:      (global $foo (mut (ref string)) (string.const "foo"))
+  (global $foo (mut (ref string)) (string.const "foo"))
+
+  ;; CHECK:      (global $bar (mut (ref string)) (string.const "bar"))
+  (global $bar (mut (ref string)) (string.const "bar"))
+
+  ;; CHECK:      (global $baz (mut (ref string)) (string.const "baz"))
+  (global $baz (mut (ref string)) (string.const "baz"))
+
+  ;; CHECK:      (func $set (type $0)
+  ;; CHECK-NEXT:  (global.set $foo
+  ;; CHECK-NEXT:   (string.const "foo")
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (global.set $bar
+  ;; CHECK-NEXT:   (string.const "BAR_BAR_BAR")
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $set
+    ;; Modify $foo to the same value as it begins.
+    (global.set $foo
+      (string.const "foo")
+    )
+    ;; Modify $bar to a new value
+    (global.set $bar
+      (string.const "BAR_BAR_BAR")
+    )
+    ;; Do not modify $baz at all.
+  )
+
+  ;; CHECK:      (func $get (type $0)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (string.const "foo")
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (global.get $bar)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (string.const "baz")
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $get
+    ;; $foo and $baz can be optimized, but not $bar.
+    (drop
+      (global.get $foo)
+    )
+    (drop
+      (global.get $bar)
+    )
+    (drop
+      (global.get $baz)
+    )
+  )
+)