1 files changed, 34 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/wasm/regress/baseline-bytereg.js b/js/src/jit-test/tests/wasm/regress/baseline-bytereg.js
new file mode 100644
index 0000000000..8bdcc32618
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/regress/baseline-bytereg.js
@@ -0,0 +1,34 @@
+// Bug 1322450 is about the baseline compiler not properly handling a byte store
+// from a wider datum on 32-bit x86 because it does not move the value to be
+// stored to a valid byte register if it is in a 32-bit register that does not
+// have a byte part (EDI/ESI/EBP).
+//
+// This test is white-box because it knows about the register allocation order:
+// the two values pushed onto the stack occupy EAX and ECX, and the i64.store8
+// will use EDX for the index and (EDI or ESI or EBP) for the low register of
+// the value to be stored.  The i64.store8 instruction will then assert in the
+// assembler.
+//
+// If the baseline compiler starts allocating registers in a different order
+// then this test will be ineffective.
+
+wasmEvalText(`(module
+    (memory 1)
+    (func $run (param i64) (param i32) (param i32)
+        local.get 1
+        local.get 2
+        i32.add
+
+        local.get 1
+        local.get 2
+        i32.add
+
+        i32.const 0
+        local.get 0
+        i64.store8
+
+        drop
+        drop
+    )
+    (export "run" (func $run))
+)`);