1 files changed, 63 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/ion/merge-phi-usage-analysis.js b/js/src/jit-test/tests/ion/merge-phi-usage-analysis.js
new file mode 100644
index 0000000000..f239a8faf2
--- /dev/null
+++ b/js/src/jit-test/tests/ion/merge-phi-usage-analysis.js
@@ -0,0 +1,63 @@
+
+function expensive() {
+    with({}) {}
+}
+
+function phi_merge_0(i) {
+    // These computations can overflow, if the output is not truncated.
+    i = i | 0;
+    var a0 = i + i;
+    var a1 = i + i;
+
+    if ((a1 | 0) - ((2 * i) | 0)) {
+        // Good candidate for branch pruning, which marks only a1 as having
+        // removed uses.
+        expensive();
+        expensive();
+        expensive();
+        expensive();
+        expensive();
+    }
+
+    // Simple branch made to let GVN merge the Phi instructions.
+    if (a1 % 3 == 1) {
+        a1 = 2 * i;
+        a0 = 2 * i;
+    }
+
+    // a0 is never used, but a1 is truncated.
+    return a1 | 0;
+}
+
+function phi_merge_1(i) {
+    // These computations can overflow, if the output is not truncated.
+    i = i | 0;
+    var a1 = i + i;
+    var a0 = i + i;
+
+    if ((a1 | 0) - ((2 * i) | 0)) {
+        // Good candidate for branch pruning, which marks only a1 as having
+        // removed uses.
+        expensive();
+        expensive();
+        expensive();
+        expensive();
+        expensive();
+    }
+
+    // Simple branch made to let GVN merge the Phi instructions.
+    if (a1 % 3 == 1) {
+        a1 = 2 * i;
+        a0 = 2 * i;
+    }
+
+    // a0 is never used, but a1 is truncated.
+    return a1 | 0;
+}
+
+for (var j = 0; j < 300; j++) {
+    for (var i = 1; i == (i | 0); i = 2 * i + 1) {
+        assertEq(phi_merge_0(i) < 0x80000000, true);
+        assertEq(phi_merge_1(i) < 0x80000000, true);
+    }
+}